https://wiki.restarters.net/api.php?action=feedcontributions&user=Pleriche&feedformat=atomRestarters Wiki - User contributions [en]2024-03-19T06:18:12ZUser contributionsMediaWiki 1.38.2https://wiki.restarters.net/index.php?title=Basic_electronic_components&diff=3600Basic electronic components2020-06-29T10:59:13Z<p>Pleriche: /* Transformers */</p>
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<div>This page covers the basic electronic components: resistors, capacitors, inductors, transformers and quartz crystals, how to identify them and understand their common failure modes, and how to test them.<br />
<br />
==Summary==<br />
The most basic electronic circuit elements providing the "furniture" of an electronic circuit are resistors and potentiometers (or variable resistors), capacitors of various sorts, inductors and transformers, and quartz crystals. We describe below how to identify them, what they do, how they sometimes fail and how to test them.<br />
<br />
You can read this page on its own if you like, but if you're not already familiar with basic electrical and electronic theory you my find you get more out of it if you first read [[Electric circuits, volts amps watts and ohms]].<br />
<br />
==Resistors==<br />
[[File:Img_1902a.jpg|180px|thumb|left|Wire-ended resistors.]]<br />
[[File:Img_1912a.jpg|180px|thumb|right|Surface mount resistors.]]<br />
In many circuits, resistors are the commonest components. They are also generally the cheapest. Their purpose is to resist the flow of electricity, either to limit the current for a given applied voltage (electrical pressure), or to allow a certain voltage (pressure) to build up when a given current flows. Most consist of a thin film of oxide or carbon deposited on a ceramic base. Heat is always generated in a resistor as the current flows, often only a tiny amount but sometimes it can be quite large.<br />
<br />
Occasionally you might come across a thermistor, which is a resistor whose resistance decreases markedly with increasing temperature, or a light-dependant resistor (LDR) whose resistance decreases with increasing light levels.<br />
<br />
Resistance is measured in Ohms (Ω), kilOhms (kΩ - thousands of Ohms), or megOhms (MΩ - millions of Ohms).<br />
<br />
As an interesting aside, whilst resistors may be the commonest and cheapest components in a conventional circuit, they are expensive to fabricate on a silicon chip as they take up a lot of space. Consequently, a chip may contain billions of transistors but few if any resistors at all!<br />
<br />
===Identification===<br />
Resistors have 2 leads and very commonly their resistance is denoted by a number of coloured bands (see [[Wikipedia:Electronic_color_code#Resistor_color-coding|resistor colour code]]).<br />
<br />
Surface mount resistors are usually black, rectangular, and with a silvery solder pad on each end. They range in size from a few millimetres down to a fraction of a millimetre.<br />
<br />
A power resistor is larger than a regular one allowing it to dissipate the required amount of heat. Often, its value will be printed on it instead of being colour coded.<br />
<br />
===Fault-finding and Repair===<br />
Resistors are usually very reliable. When they fail, generally through overheating, it's almost always as a result of some other component failing and causing too much current to flow. In poorly designed equipment having inadequate provision for heat to escape, moderate overheating over a long period of time may cause a failure.<br />
<br />
==Potentiometers==<br />
[[File:Img_1904a.jpg|180px|thumb|right|Potentiometers.]]<br />
A potentiometer (or pot, for short) is simply a resistor with a 3rd connection that can be moved to any point along its length, so as to tap off any desired portion of the total resistance.<br />
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===Identification===<br />
Potentiometers are very commonly used for the volume control in audio equipment (though being superseded by digital controls). These have a spindle with a front panel knob attached, or sometimes a knurled wheel with the edge exposed for adjustment. Twin-gang potentiometers consisting of two mounted on one spindle are often found in stereo equipment for controlling the volume of both stereo channels.<br />
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Small potentiometers with a slotted screw head are often found inside equipment for one-time adjustment during manufacture and testing.<br />
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===Fault-finding and Repair===<br />
Potentiometers are much less reliable than fixed resistors. The track can get worn out or crack, or the pressure of the slider on the track can weaken. Sometimes the pressure can be increased by bending the metal slider, though pots are not normally designed to be taken apart and are usually best replaced for a lasting fix.<br />
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A quick fix which sometimes works is to squirt switch cleaning fluid into the casing through any gaps or slots you can see, such as beneath the terminals, then repeatedly turn the knob from one end of its travel to the other.<br />
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If you find a slotted screw head pot inside a piece of equipment, never adjust it unless you know what it's for and how to find the correct position. Even then, it's worth marking the original position before starting so you can always return to it.<br />
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==Capacitors==<br />
[[File:Img_1905a.jpg|180px|thumb|left|Low value capacitors.]]<br />
Hopefully you will recall that since like charges repel, electricity hates piling up and as a consequence a circuit must be completed (for example by closing a switch) before a current can flow.<br />
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[[File:Img_1917a.jpg|180px|thumb|right|Surface mount capacitors.]]<br />
However, electricity will pile up to a limited extent if you apply a voltage (an electrical pressure), but only until the back-pressure equals the voltage you apply.<br />
<br />
[[File:Img_1906a.jpg|180px|thumb|left|Electrolytic capacitors.]]If there is nowhere much for the electricity to go, that will be very soon, like if you tried to send lots of cars down a short cul-de-sac. But you can make life easier for the electricity if you give it room to spread out, like if there were a large car park at the end of the cul-de-sac. And when you stop pushing the electricity in, it'll all come piling out again as soon as the pressure is released.<br />
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[[File:Img_1907a.jpg|180px|thumb|right|Tantalum capacitors.]]<br />
A capacitor is a device which allows electricity to pile up by providing space for it to spread out. One of the simplest types just consists of two long strips of aluminium foil separated by a thin insulating strip of plastic, and then rolled up, with a wire connected to each strip. If you connect it to the two terminals of a battery, positive charge will flow out of the positive terminal of the battery and onto one of the strips. Since it's in close proximity to the other strip, it repels an equal amount of positive charge from that strip, which flows back into the negative terminal of the battery. If you disconnect the battery, the electrical charge remains until you connect the two wires together, allowing it to discharge.<br />
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A car park has a capacity, but a capacitor has a capacitance. It's measured in Farads (F), or more usually microFarads (μF - millionths of a Farad), nanoFarads (nF - billionths of a Farad), or picoFarads (pF - million-millionths of a Farad).<br />
<br />
You can double the capacitance by doubling the surface area that the charge has to spread out in. But you can also do so by halving the thickness of the insulating layer, as this allows the charge on one side to more easily push charge out of the other. But a large enough voltage would destructively break through a very thin insulating layer. A capacitor therefore also has a voltage rating, being the highest voltage that it can safely withstand. This must on no account be exceeded.<br />
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Capacitors are used whenever the circuit designer needs to smooth out fluctuations, or when it is required to allow fluctuations (e.g. an audio signal) to flow from one part of a circuit to another whilst blocking any net flow.<br />
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===Identification===<br />
Like resistors, capacitors have just two connections, but they come in a wide range of shapes and sizes. They usually have their capacitance and voltage rating printed on them, and for some types, a maximum temperature.<br />
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Low value surface mount capacitors are usually grey or buff in colour, rectangular, and with a silvery solder pad on each end. They are typically a few millimetres in length.<br />
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Electrolytic capacitors are very frequently used where a high value of capacitance is required. Much the most common are aluminium types, which can be recognised by the cylindrical aluminium case, usually with a plastic film cover. One lead is marked negative ("-") on the adjacent side or end of the case.<br />
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Tantalum capacitors are a higher quality (and more expensive) type of electrolytic capacitor using tantalum instead of aluminium. They come as a resin coated bead. Usually, the positive lead is marked "+".<br />
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Capacitors connected directly to the mains require a special safety rating. This is Class X for those connected across the mains supply, where a failure could present a fire hazard, and Class Y for those connected between the mains and ground, where the failure could result in an electric shock hazard. Such capacitors must always be replaced with ones of the same class and at least the same voltage rating.<br />
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===Fault-finding and Repair===<br />
[[File:Img_1789a.jpg|180px|thumb|right|A bulging electrolytic capacitor.]]<br />
Capacitors are usually very reliable except for electrolytic types, which are one of the commonest causes of failure in electronic equipment.<br />
<br />
In an electrolytic capacitor, the insulating layer consists of an electrochemically formed film of aluminium oxide with a thickness of only a matter of millionths of a millimetre. This can deteriorate after a long period of disuse (many years) or a shorter period close to or beyond its maximum voltage and/or temperature rating. Also, the liquid used to form the insulating layer can dry out. Poor quality electrolytic capacitors are quite often seen which have failed within their ratings.<br />
<br />
A failing electrolytic capacitor can often be recognised as a build up of internal pressure may cause the top to bulge, or the capacitor no longer to sit flush with the board, or electrolyte to leak from the bottom. At this stage it probably won't be performing well, causing the equipment to malfunction. If not replaced, it may even explode. However the fact that an electrolytic capacitor shows no visible sign of deterioration is by no means a reliable indicator that it's good.<br />
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[[File:Component_tester.jpg|180px|thumb|left|A cheap component tester with ESR function.]]The simplest reliable method of testing an electrolytic capacitor is with an ESR (Equivalent Series Resistance) tester. A basic one with a graphical display but without a case is available very cheaply from Far Eastern sellers. This is an excellent investment as it will also identify and test many other types of component. A good electrolytic capacitor should show an ESR of a fraction of an ohm, and a vloss (another measure given by these testers) of a fraction of a percent.<br />
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If an electrolytic capacitor has to be replaced it's very important to fit the replacement the right way round (the "+" or the "-" marking on the same side) as otherwise the electrolytic forming process will be reversed and it will very rapidly fail.<br />
<br />
Also, it's always a good idea to replace it with one with a higher voltage and/or temperature rating as the original may have been under-rated. Never ever use a lower rated replacement. If a replacement with the same capacity is not available, a higher value up to twice the original will almost invariably work well, or possibly even better, as there is in any case considerable variation in the capacitance of identically marked electrolytic capacitors.<br />
<br />
The site [http://badcaps.net/ badcaps.net] has useful tips on replacing electrolytic capacitors.<br />
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==Inductors==<br />
[[File:Img_1953a.jpg|180px|thumb|right|Inductors.]]<br />
An inductor simply consists of a coil of wire. When a current flows it creates a magnetic field, which stores energy. By winding it around a core of magnetic material such as iron or ferrite, this gets magnetised, greatly increasing the amount of energy that is stored.<br />
<br />
Whereas a capacitor stores energy in as electrical charge and can be used to smooth out variations in voltage, an inductor stores energy as magnetic flux and tends to smooth out variations in current flow. In such an application it's often called a choke as it chokes variations in the flow.<br />
<br />
In fact, there is a beautiful symmetry between the mathematical equations describing capacitors and inductors. If you combine an inductor and a capacitor in a circuit, this symmetry blossoms and something rather special happens. A voltage on the capacitor tries to drive a current through the inductor, but once the current gets going the inductor tries to keep it going, and ends up driving the charge onto the other side of the capacitor. So it flows backwards and forwards at a very regular rate, exactly like a child swinging back and forth on a swing. By using a variable capacitor (or a variable inductor), the rate can be altered. This is how nearly all older AM and FM radios tune in the station you want.<br />
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Inductance is measured in Henrys (H), milliHenrys (mH - thousandths of a Henry), or microHenrys (μH - millionths of a Henry).<br />
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===Identification===<br />
[[File:Common_mode_choke.jpeg|180px|thumb|left|A common mode choke used to filter the mains input to a power supply.]]<br />
The smallest value inductors consist of no more than a coil of thick wire standing up from the circuit board. Some small inductors consist of a toroid of ferrite with the coil of wire wound around it, and are easily spotted. In others, the coil is wound around a ferrite core shaped like a cotton reel, which may be fitted snugly inside a hollow cylinder of ferrite. A common mode choke has two windings, sometimes used to filter both the live and neutral feeds to a power supply. This then is essentially no different from a transformer.<br />
<br />
For large values of inductance a laminated iron core is used. This is rarely seen in reasonably modern equipment, but vintage valve radios often used two large capacitors and an iron-cored inductor to smooth the rectified mains.<br />
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An inductor frequently has no markings on it.<br />
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===Fault-finding and Repair===<br />
There is very little to go wrong in an inductor apart from possibly a badly soldered joint. A very heavy current could cause an inductor to overheat or burn out, but probably not before much damage had been done elsewhere in the circuit.<br />
<br />
==Transformers==<br />
[[File:Img_1940a.jpg|180px|thumb|left|A small toroidal ferrite transformer with 3 windings.]]<br />
[[File:Img_1948a.jpg|180px|thumb|right|A mains transformer.]]<br />
A transformer is simply an inductor with two (or more) coils of wire.<br />
<br />
An electric current always creates a magnetic field which loops around the current, and a change in the magnetism looping through a circuit generates a voltage in that circuit. So in a transformer, we apply power to one coil of wire, the primary, and the magnetic flux which this creates induces a voltage in the other coil(s), the secondary(s). But it only works while the magnetic field is changing, and so a transformer can only be used for [[Glossary:AC|AC]], not [[Glossary:DC|DC]].<br />
<br />
Transformers are very useful for two reasons:<br />
* If the secondary coil has more or fewer turns than the primary, the voltage induced in it will be greater or less than that applied to the primary, in proportion.<br />
* Since the only connection between the primary and the secondary is magnetic, they are electrically isolated from each other. This can be useful for safety reasons, or where the circuit designer needs to block a net flow of current from one part to another.<br />
<br />
===Identification===<br />
[[File:Img_1944a.jpg|180px|thumb|right|A toroidal mains transformer.]]<br />
If you know how to identify an inductor, then a transformer looks exactly the same except that it has at least 3 wires coming out of it, and nearly always 4 or more.<br />
<br />
Older mains powered electronic equipment almost always contains an iron cored mains transformer, which is easy to spot. Good quality audio equipment sometimes uses a toroidal mains transformer as this type produces less stray magnetic field and hence less background hum in the audio output. Newer equipment tends to use a much smaller transformer with a ferrite core.<br />
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===Fault-finding and Repair===<br />
Mains transformers may be required to handle a substantial amount of power, and so in fault conditions they can become very hot. If this results in a breakdown of the insulation between two adjacent turns of either the primary or the secondary, these turns will act like a short-circuited secondary and become very hot indeed.<br />
<br />
Rewinding a burnt out mains transformer is not difficult, but rarely would be worth the considerable time and patience required.<br />
<br />
==Crystals and Ceramic Resonators==<br />
[[File:Crystal-opened.jpg|200px|thumb|right|A quartz crystal removed from its can.]]<br />
A quartz crystal is commonly used where the designer needs to generate a fixed frequency oscillation. Quartz is a piezoelectric material, which means that a voltage apears across opposite faces if you stress it, and conversly, applying a voltage causes a similar stress. A piece of quartz can be cut and polished so as to resonate (or ring like a bell) at a very precise chosen frequency. Placed in an electronic circuit which amplifies and sustains the resonance, you have a simple and very stable frequency source. The photo shows a crystal that has been removed from its protective can.<br />
<br />
Apart from quartz clocks, digital equipment very commonly contains a crystal to provide the oscillation which steps it through its processing steps. In a digitally tuned radio a crystal oscillator generates a reference frequency from which the desired frequency is generated digitally in order to tune the chosen station. Some vintage FM radios contained three crystals in a glass envelope similar to a valve. This allowed three stations to be tuned by selecting one of the three crystals.<br />
<br />
Ceramic resonators operate in the same way but are cheaper and less precise in their frequency. These generally use lead zirconium titanate instead of quartz and may be used instead of a crystal in digital equipment where the frequency is not also being used for precise timing. A ceramic resonator may also be used in the [[How_radios_work#Superhet|IF stages]] of a radio to select the required frequency. These resonators have 3 leads, one attached to each end of one face of the resonator, and the third attached to the opposite face. The signal is applied to the first and third, causing it to resonate along its whole length. The signal is reproduced between the second and third leads, with any other off-tune frequencies greatly reduced.<br />
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===Identification===<br />
[[File:Quartz_crystals.jpg|200px|thumb|right|Surface mount and wire-ended crystals.]]<br />
Quartz crystals are usually easy to spot as they come in a silvery metal can. In the case of quartz clocks they are usually cylindrical and quite small. Often, you will see two small capacitors adjacent to a crystal, which are required to allow it to vibrate freely. Occasionally, one of these might be a variable capacitor allowing a fine tuning of its resonant frequency, already accurate to around 10 parts per million.<br />
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[[File:A 16MHz ceramic resonator.jpg|120px|thumb|left|A 16MHz ceramic resonator]]<br />
A ceramic resonator looks very smilar to a small capacitor, except that it may have 3 or even 4 leads.<br />
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===Fault-finding and Repair===<br />
Quartz crystals are usually reliable but failures are not unknown. Since the crystal itself is suspended only by its leads to allow it to vibrate freely it can be damaged by shock or vibration, perhaps combined with a weak joint resulting from a manufacturing defect.<br />
<br />
There is no simple way of testing a quartz crystal apart from by substitution. A multimeter applied to its leads will show it as an open circuit since quartz is a very good insulator.<br />
<br />
==And now ...==<br />
... you might like to continue by reading about [[Active components]].</div>Plerichehttps://wiki.restarters.net/index.php?title=Portable_radios&diff=3596Portable radios2020-06-29T09:59:33Z<p>Pleriche: /* Types of radio */ Broken Glossary link - was Flossary!</p>
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<div>This page covers the practical aspects of diagnosing and fixing portable radios.<br />
<br />
==Summary==<br />
Many fixable problems with portable radios are common to many types of electronic gadgets and only require a rudimentary understanding of electrical theory. A slightly deeper understanding may allow you to localise some of the less obvious problems. This is covered in the companion page [[How radios work]], which also explains any abbreviations or technical terms you may not be familiar with in this page.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Mains powered radios (except those powered by a separate "wall cube" type adapter) are likely to contain dangerous voltages when plugged in. Don't plug them in while the case is open unless you (and any bystanders) understand how to manage the risks.<br />
<br />
::Virtually all vintage valve radios operate at high voltages. A large smoothing capacitor may retain a dangerous voltage after the radio is switched off.<br />
<br />
==Types of radio==<br />
<br />
The oldest radios you might come across use [[Glossary:Valve|valves]]. Individual components are wired together rather than being mounted on a printed circuit board. They are often [[Glossary:AM|AM]] only (MW and LW, possibly SW) but post war ones may also receive [[Glossary:FM|FM]].<br />
<br />
Vintage transistor radios date mainly from the 1950's or 60's and use [[Glossary:Germanium|germanium]] transistors, which are less robust than more modern [[Glossary:Silicon|silicon]] types. Later radios use silicon transistors, and increasingly through the 1980's and 90's used [[Glossary:Integrated Circuit|integrated circuits]] for some or all of the internal functions.<br />
<br />
All the above types of radio almost invariably follow the [[How_radios_work#Superhet|superhet]] design.<br />
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Digital ([[Glossary:DAB|DAB]]) radios are the latest type, introduced in the late 1990's. Some also incorporate FM.<br />
<br />
==Common problems==<br />
Telescopic aerials on FM and DAB radios are relatively easily bent or broken. Close inspection will show whether there is any chance of a repair. As a temporary measure, replace it with a length of wire (say, 50cm, or similar in length to the original aerial). You should be able to secure it at one end under a screw securing the base of the aerial.<br />
<br />
Look out for other purely mechanical problems such as the linkages, pulleys and strings which operate the tuning dial on an older radio. Corroded contacts in the battery compartment is common in most types of battery operated equipment, resulting from dead and leaking batteries being left in the device.<br />
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If there is no sound a very simple test is to try with headphones (assuming there is a headphone socket). If it works with headphones it could be a problem with the speaker or the headphone socket. (The headphone socket incorporates a switch which mutes the speaker when you plug headphones in. A fault with this could be the problem.)<br />
<br />
Opening a radio is not always straightforward but is nearly always possible once you find the right screws. Sometimes you may come across a combined radio/cassette/CD player which won't come apart easily. You may have to search for hidden screws underneath a label, rubber foot or speaker grill, and the order of disassembly (and reassembly!) may be critical.<br />
<br />
Once inside, look for common problems such as broken or shorting wires, signs of burnt or overheating components and bulging electrolytic [[Basic_electronic_components#Fault-finding_and_Repair_3|capacitors]].<br />
<br />
If the radio shows no signs of life, check for a [[Power_supplies|power supply]] problem. <br />
<br />
If you can identify the audio amplifier as a separate module and can identify the audio input to it, touching this with a finger should produce a hum from the loudspeaker, or touching it with a metal screwdriver while you hold the metal shaft should produce a crackle. This indicates that the audio amplifier is working and the fault is probably in the tuner. ('''Never''' try this on a valve or other mains powered radio.)<br />
<br />
[[Passive_components#Switches_and_Push-Buttons|Push button switches]] can become unreliable with use. Beneath the external button there is often a standard tactile switch soldered to the circuit board. Sometimes a simple solution is to insert some packing, such as a folded piece of paper, between the external button and the tactile switch, allowing a little more pressure to be applied. Replacements are available very cheaply on eBay in a range of sizes. As a short term measure you may be able to swap an unreliable switch with another on the same circuit board operating a function that is rarely if ever needed.<br />
<br />
==AM/FM radios==<br />
Vintage valve radios are likely to contain a thick layer of dust over the internal components which may impede cooling. Clean it out with a vacuum cleaner.<br />
<br />
A valve radio which has seen much use may benefit from new valves. These may be available on eBay, particularly the miniature all-glass types generally used in post war radios.<br />
<br />
AM only and AM/FM radios contain a number of tuned circuits which are adjusted by the manufacturer to the same frequency or frequencies by means of trimmer capacitors having an adjustable screw head and coils with a ferrite core that can be screwed in or out. DO NOT adjust these - you need specialist equipment and the service handbook for the particular radio in order to do so, without which you are very likely to make the radio much worse rather than any better. As a last resort, having understood how a [[How_radios_work#Superhet|superhet]] works, adjust one at a time, noting the exact position of the screw head before the adjustment and returning it to the same position if there is no significant improvement. If you succeed in making an improvement, make sure the improvement is maintained across the tuning dial.<br />
<br />
A crackly volume control is a common problem in older radios. This will be a [[Basic_electronic_components#Potentiometers|potentiometer]] and may well be a standard widely available part, relatively easily fitted. As a short term measure you may be able to effect an improvement by squirting switch cleaner into it through a gap in the case. Operating the control repeatedly from one limit to the other should then help to shift any dirt on the carbon track.<br />
<br />
In the case of a vintage transistor radio, check the type codes on the [[Active_components#Transistors|transistors]] and look them up on the Internet. If they are germanium rather than silicon types, these are much less robust and it is possible that one has failed. There's a chance this might still leaving the radio working, but only just.<br />
<br />
If you can identify which lead of a transistor is which, try testing the voltage between the base and the emitter, which should be around 0.3V for germanium types and 0.7V for silicon. There should be a greater voltage between the emitter and the collector, probably at least 1V and more likely several volts. If there is no voltage that is a strong indication that the transistor has failed.<br />
<br />
If you remove transistors for testing (you can use the transistor test function on many cheap [[How_to_use_a_multimeter|multimeters]]) you should unsolder them using the minimum of heat in the case of germanium types as too much heat can damage them. It's a good idea to grip each lead with pliers between the transistor body and the circuit board while soldering or unsoldering. This will act as a "heat shunt" to conduct away much of the heat.<br />
<br />
Given a circuit diagram or sufficient experience to identify the various sections, you may be able to narrow down a fault with a signal injector and/or an oscilloscope, but if you know how to use them and to read a circuit diagram you probably won't be reading this page!<br />
<br />
==DAB radios==<br />
DAB radios ought to be very reliable but experience shows this not always to be the case. The reasons are poorly understood in the Restart community, as faults in the digital circuits often cannot be pinned down accurately. Suggested causes are:<br />
* Brittle solder joints or solder [https://www.maximintegrated.com/en/app-notes/index.mvp/id/5250 whiskers] (lead-free solder used in modern equipment is more brittle than older lead/tin solder and prone to the growth if tin "whiskers" which can cause short circuits).<br />
* Manufacturing defects in the integrated circuits.<br />
* Inaccurate or unstable power supply voltage (most digital circuits require an accurately controlled power supply of 3.3 or 5V with a margin of only +/-5%).<br />
<br />
However, you should at least be able to narrow the fault down somewhat. Here are a few simple tips:<br />
* Check the output voltage(s) of the power supply.<br />
* Check the ribbon cables joining the various modules are properly seated, and try reseating them.<br />
* For a DAB radio also having an FM waveband, check whether it works on FM. If so, the fault is in the DAB tuner. If not it's in the audio section, which is common to both wavebands.<br />
* If there is no sound from the speaker, check whether the headphone socket works. If so, the fault is in the headphone socket itself, the loudspeaker, or the wiring between and around them both.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Glossary:P-type&diff=3595Glossary:P-type2020-06-26T21:29:42Z<p>Pleriche: </p>
<hr />
<div>P-type is the name given to a [[Glossary:Semiconductor|Semiconductor]] material doped with an impurity whose atoms have one too few [[Glossary:Electron|electrons]] to match the crystal lattice. These result in [[Glossary:Hole|holes]] which can effectively move about and carry an electric current as positive charges. Think of bubbles in a liquid. These "holes" in the liquid effectively have a negative weight and so tend to rise against gravity.</div>Plerichehttps://wiki.restarters.net/index.php?title=Glossary:N-type&diff=3594Glossary:N-type2020-06-26T21:26:45Z<p>Pleriche: </p>
<hr />
<div>N-type is the name given to a [[Glossary:Semiconductor|Semiconductor]] material doped with an impurity whose atoms have one too many [[Glossary:Electron|electrons]] to match the crystal lattice. These "spare" electrons can carry an electric current as negative charges.</div>Plerichehttps://wiki.restarters.net/index.php?title=Glossary:Multimeter&diff=3593Glossary:Multimeter2020-06-26T21:24:27Z<p>Pleriche: </p>
<hr />
<div>A multimeter is an electrical test instrument which measures voltage, current, resistance and often several other things. Most usually they have a digital readout but analogue ones with a dial are also available. See [[How to use a multimeter]] in the Wiki.</div>Plerichehttps://wiki.restarters.net/index.php?title=Quadcopters_and_drones&diff=3592Quadcopters and drones2020-06-26T21:22:09Z<p>Pleriche: Electrical Faults filled out</p>
<hr />
<div>This is currently a skeleton page. Please help by adding your contributions either here or in the associated Discussion page.<br />
<br />
This page will cover flying toys as well as larger and more serious drones.<br />
<br />
==Summary==<br />
In recent years, drones, both amateur and professional, and flying toys of various kinds have been made possible at reasonable cost by the availability of lithium batteries with a high power to weight ratio, and cheap control electronics and sensors. Particularly with toys, damaging crashes are common, but other faults may also arise.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Be sure you know how to fly your device safely. Rotating propeller blades can be very dangerous, especially the larger ones.<br />
::There are strict laws in many territories governing the use of drones and quadcopters, as well as radio controlled model aircraft of all types. See [[#Legal|Legal]] below.<br />
<br />
==Basic Principles==<br />
===Aerodynamic Principles===<br />
The idea of a machine which screws itself into the air dates back to Leonardo da Vinci in 1493, but it was another 450 years before the first practical helicopter took to the air.<br />
<br />
Unfortunately for Leonardo, Sir Isaac Newton had yet to formulate his Laws of Motion (published only in 1687). According to his 3rd law (action and reaction are equal and opposite), in forcing its rotor blades to turn against air resistance, the engine of a helicopter necessarily applies and equal and opposite turning force on the aircraft's body. So nearly all helicopters have a tail rotor to counteract this turning force. If a helicopter looses its tail rotor it spins out of control - the chances of surviving such an accident are very slim indeed.<br />
<br />
Just a few helicopters and nearly all drones and flying toys counteract the turning force in a different way. They have two or more rotors spinning in opposite directions. The Boeing [[Wikipedia:Boeing_CH-47_Chinook|Chinook]] is an example. Some helicopters and many toys have two counter-rotating rotors on the same spindle. Quadcopters have 4 rotors but you can have any number, provided its an even number, and provided you make half of them spin one way and the other half spin the other way in order to balance out the twisting force.<br />
<br />
===Controls===<br />
A great advantage of having multiple rotors is that you can very simply manoeuvre your drone by deliberately unbalancing the rotors slightly. Applying a little more power to the two rear rotors of a quadcopter causes it to tip forward and so start moving forward. You can do the same with the rear two to make it move backwards, or two side rotors to make it move sideways. Equally, you can apply slightly more power to the two clockwise rotors to unbalance the twisting forces and make it turn anticlockwise, or vice versa. This is known as yaw.<br />
<br />
A hand-held controller with two joysticks is normally provided. Typically one controls forwards, backwards and sideways motion, and the other the overall power and yaw. A radio link transmits commands to the device.<br />
<br />
Model helicopters have two concentric counter-rotating rotors. Yaw is achieved by increasing the power to one and decreasing it to the other. A small propeller on the tail pointing upwards (unlike nearly all full size helicopters) tips the craft forwards or backwards to control the motion.<br />
<br />
You may come across a flying toy simply consisting of a ball with a pair of counter-rotating rotors. An infra-red sensor in the bottom detects the proximity of the ground and boosts the power to keep it airborne.<br />
<br />
The more sophisticated quadcopters and drones have a variety of sensors. A camera is common, which may record to an SDCard or transmit real-time video to the controller or a smartphone app. An air pressure sensor allows it to roughly maintain a given height, making it quite a lot easier to control. There may be a magnetometer to enable it to maintain a given magnetic compass heading, or a proximity sensor to enale it to make an automatic soft landing. A GPS module may be included, allowing it to follow a predetermined path or to automatically return to base. A variety of sensors may be included to implement a "follow me" function to film your sports activity.<br />
<br />
==Fault-finding==<br />
Common faults are physical breakages, unstable flight, and low power. Spares for the more popular models are availble from Far-Eastern suppliers such as [https://www.aliexpress.com/ AliExpress] or [https://www.banggood.com/ Banggood] and through eBay shops, if not locally.<br />
<br />
===Breakages and Mechanical Faults===<br />
Crashes are common, especially amongst toys and in the hands of youngsters, and these can lead to breakages. To minimise damage, read the instructions carefully and make sure you know how to kill the rotors dead in the event of a crash.<br />
<br />
Cheap ones are often so light that they can fall out of the sky with relative impunity, but if the rotors continue to receive power after becoming entangled or jammed, then damage may result.<br />
<br />
It may be possible to repair damage to a plastic shell with 2-part [[Sticky_Stuff#Epoxy|epoxy glue]].<br />
<br />
Often a set of spare rotor blades and rotor guards are provided, and for the more popular brands, spares are easily obtained. In fact the smaller rotors are fairly indestructible but may simply be a push-fit on the motor spindle. In a crash, they can sometimes come off and get lost. The clockwise and counter-clockwise rotors should be easily distinguisahble, for example marked A and B. Make sure you replace an A with an A or a B with a B, or it will be impossible to fly.<br />
<br />
If the problem is unstable flight, try flicking each rotor in turn. They should all spin equally freely. If not, this is likely to be the cause of the problem.<br />
<br />
Hairs can get tangled around the spindle between a rotor and its motor, causing additional friction and loss of control. A magnifying glass and a pair of tweezers may be helpful in removing it, but this will get difficult if the hairs get into the motor bearing.<br />
<br />
If the quadcopter has been disassembled (or has never flown well) there could be something else rubbing on a spindle. For example, there might be a rubber boot over each end of the motor to make it fit snugly in its housing, and this could be rubbing against the spindle if not correctly fitted.<br />
<br />
In some quadcopters the rotors are driven directly from the motor spindles whereas in others they are driven via gears to reduce the speed of rotation. Check that the gears are undamaged, clean and free of anything which might obstruct them.<br />
<br />
===Electrical Faults===<br />
The electronic controls should be highly reliable but wires and solder joints can get broken. Wires can easily get pinched between two halves of the shell on reassembly.<br />
<br />
Motors can fail, either completely or they may loose power. Fortunately, replacements are available from Far Eastern sources and they are relatively easily fitted though it may require fine soldering.<br />
There are two distinct types of motor:<br />
<br />
The smaller ones use [[Glossary:Coreless_motor|coreless motors]]. These have two wires, and whilst you can make them spin in the reverse direction simply by swapping the wires, the arrangement of the brushes is normally optimised either for clockwise or anticlockwise service. Failure of the brushes is probably the most common problem. Sets of four, two clockwise and two anticlockwise are often advertised, commonly distinguisable by one pair having red and blue wires and the other pair white and black.<br />
<br />
You can test a coreless motor simply by connecting it to a 3V battery, but the fact that it spins won't necessarily confirm that it can spin as freely as it should.<br />
<br />
Larger drones invariably use [[Glossary:Brushless_Motor|brushless motors]]. These have 3 wires and rely an electronic circuit to drive a current through different pairs of wires as the spindle turns. Simply by reversing the phasing of the currents, it can be made to spin in the opposite direction. In fact, if you get two of the wires reversed in replacing such a motor it will spin in the wrong direction.<br />
<br />
You can't so easily perform a functional test on a brushless motor, but the resistance of each of the 3 pairs of leads as measured with a [[Glossary:Multimeter|multimeter]] should be very low indeed. If any is open circuit then the motor has probably burned out.<br />
<br />
==Legal==<br />
Legal restrictions on the use of airborne devices such as drones will vary from one country to another.<br />
*In the UK you need a licence if your device is over 250g. See [https://www.gov.uk/government/news/drones-are-you-flying-yours-safely-and-legally Drones: how to fly them safely and legally].<br />
<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Quadcopters_and_drones&diff=3591Quadcopters and drones2020-06-25T21:50:51Z<p>Pleriche: /* Breakages and Mechanical Faults */ Started Electrical Faults</p>
<hr />
<div>This is currently a skeleton page. Please help by adding your contributions either here or in the associated Discussion page.<br />
<br />
This page will cover flying toys as well as larger and more serious drones.<br />
<br />
==Summary==<br />
In recent years, drones, both amateur and professional, and flying toys of various kinds have been made possible at reasonable cost by the availability of lithium batteries with a high power to weight ratio, and cheap control electronics and sensors. Particularly with toys, damaging crashes are common, but other faults may also arise.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Be sure you know how to fly your device safely. Rotating propeller blades can be very dangerous, especially the larger ones.<br />
::There are strict laws in many territories governing the use of drones and quadcopters, as well as radio controlled model aircraft of all types. See [[#Legal|Legal]] below.<br />
<br />
==Basic Principles==<br />
===Aerodynamic Principles===<br />
The idea of a machine which screws itself into the air dates back to Leonardo da Vinci in 1493, but it was another 450 years before the first practical helicopter took to the air.<br />
<br />
Unfortunately for Leonardo, Sir Isaac Newton had yet to formulate his Laws of Motion (published only in 1687). According to his 3rd law (action and reaction are equal and opposite), in forcing its rotor blades to turn against air resistance, the engine of a helicopter necessarily applies and equal and opposite turning force on the aircraft's body. So nearly all helicopters have a tail rotor to counteract this turning force. If a helicopter looses its tail rotor it spins out of control - the chances of surviving such an accident are very slim indeed.<br />
<br />
Just a few helicopters and nearly all drones and flying toys counteract the turning force in a different way. They have two or more rotors spinning in opposite directions. The Boeing [[Wikipedia:Boeing_CH-47_Chinook|Chinook]] is an example. Some helicopters and many toys have two counter-rotating rotors on the same spindle. Quadcopters have 4 rotors but you can have any number, provided its an even number, and provided you make half of them spin one way and the other half spin the other way in order to balance out the twisting force.<br />
<br />
===Controls===<br />
A great advantage of having multiple rotors is that you can very simply manoeuvre your drone by deliberately unbalancing the rotors slightly. Applying a little more power to the two rear rotors of a quadcopter causes it to tip forward and so start moving forward. You can do the same with the rear two to make it move backwards, or two side rotors to make it move sideways. Equally, you can apply slightly more power to the two clockwise rotors to unbalance the twisting forces and make it turn anticlockwise, or vice versa. This is known as yaw.<br />
<br />
A hand-held controller with two joysticks is normally provided. Typically one controls forwards, backwards and sideways motion, and the other the overall power and yaw. A radio link transmits commands to the device.<br />
<br />
Model helicopters have two concentric counter-rotating rotors. Yaw is achieved by increasing the power to one and decreasing it to the other. A small propeller on the tail pointing upwards (unlike nearly all full size helicopters) tips the craft forwards or backwards to control the motion.<br />
<br />
You may come across a flying toy simply consisting of a ball with a pair of counter-rotating rotors. An infra-red sensor in the bottom detects the proximity of the ground and boosts the power to keep it airborne.<br />
<br />
The more sophisticated quadcopters and drones have a variety of sensors. A camera is common, which may record to an SDCard or transmit real-time video to the controller or a smartphone app. An air pressure sensor allows it to roughly maintain a given height, making it quite a lot easier to control. There may be a magnetometer to enable it to maintain a given magnetic compass heading, or a proximity sensor to enale it to make an automatic soft landing. A GPS module may be included, allowing it to follow a predetermined path or to automatically return to base. A variety of sensors may be included to implement a "follow me" function to film your sports activity.<br />
<br />
==Fault-finding==<br />
Common faults are physical breakages, unstable flight, and low power. Spares for the more popular models are availble from FarEastern suppliers such as [https://www.aliexpress.com/ AliExpress] or [https://www.banggood.com/ Banggood] and through eBay shops, if not locally.<br />
<br />
===Breakages and Mechanical Faults===<br />
Crashes are common, especially amongst toys and in the hands of youngsters, and these can lead to breakages. Read the instructions carefully and make sure you know how to kill the rotors dead in the event of a crash.<br />
<br />
Cheap ones are often so light that they can fall out of the sky with relative impunity, but if the rotors continue to receive power after becoming entangled or jammed, then damage may result.<br />
<br />
It may be possible to repair damage to a plastic shell with 2-part [[Sticky_Stuff#Epoxy|epoxy glue]].<br />
<br />
Often a set of spare rotor blades and rotor guards are provided, and for the more popular brands, spares are easily obtained. In fact the smaller rotors are fairly indestructible but may simply be a push-fit on the motor spindle. In a crash, they can sometimes come off and get lost. The clockwise and counter-clockwise rotors should be easily distinguisahble, for example marked A and B. Make sure you relace an A with an A or a B with a B, or it will be impossible to fly.<br />
<br />
If the problem is unstable flight, try flicking each rotor in turn. They should all spin equally freely. If not, this is likely to be the cause of the problem.<br />
<br />
Hairs can get tangled around the spindle between a rotor and its motor, causing additional friction and loss of control. A magnifying glass and a pair of tweezers may be helpful in removing it, but this will get difficult if it gets into the motor bearing.<br />
<br />
If the quadcopter has been disassembled (or has never flown well) there could be something else rubbing on a spindle. For example, there might be a rubber boot over each end of the motor to make it fit snugly in its housing, and this could be rubbing against the spindle if not correctly fitted.<br />
<br />
In some quadcopters the rotors are driven directly from the motor spindles whereas in others they are driven via a pair of gears to reduce the speed of rotation. Check that the gears are undamaged, clean and free of anything which might obstruct them.<br />
<br />
===Electrical Faults===<br />
The electronic controls should be highly reliable but wires and solder joints can get broken. Wires can easily get pinched between two halves of the shell on reassembly.<br />
<br />
Motors can fail, either completely or they may loose power. Fortunately, they are relatively easily replaced though it may take a little fine soldering, and replacements are available from Far Eastern sources.<br />
<br />
The motors are of two different types:<br />
<br />
==Legal==<br />
Legal restrictions on the use of airborne devices such as drones will vary from one country to another.<br />
*In the UK you need a licence if your device is over 250g. See [https://www.gov.uk/government/news/drones-are-you-flying-yours-safely-and-legally Drones: how to fly them safely and legally].<br />
<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Quadcopters_and_drones&diff=3590Quadcopters and drones2020-06-25T21:43:57Z<p>Pleriche: /* Fault-finding */ Added Breakages and Mechanical Faults</p>
<hr />
<div>This is currently a skeleton page. Please help by adding your contributions either here or in the associated Discussion page.<br />
<br />
This page will cover flying toys as well as larger and more serious drones.<br />
<br />
==Summary==<br />
In recent years, drones, both amateur and professional, and flying toys of various kinds have been made possible at reasonable cost by the availability of lithium batteries with a high power to weight ratio, and cheap control electronics and sensors. Particularly with toys, damaging crashes are common, but other faults may also arise.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Be sure you know how to fly your device safely. Rotating propeller blades can be very dangerous, especially the larger ones.<br />
::There are strict laws in many territories governing the use of drones and quadcopters, as well as radio controlled model aircraft of all types. See [[#Legal|Legal]] below.<br />
<br />
==Basic Principles==<br />
===Aerodynamic Principles===<br />
The idea of a machine which screws itself into the air dates back to Leonardo da Vinci in 1493, but it was another 450 years before the first practical helicopter took to the air.<br />
<br />
Unfortunately for Leonardo, Sir Isaac Newton had yet to formulate his Laws of Motion (published only in 1687). According to his 3rd law (action and reaction are equal and opposite), in forcing its rotor blades to turn against air resistance, the engine of a helicopter necessarily applies and equal and opposite turning force on the aircraft's body. So nearly all helicopters have a tail rotor to counteract this turning force. If a helicopter looses its tail rotor it spins out of control - the chances of surviving such an accident are very slim indeed.<br />
<br />
Just a few helicopters and nearly all drones and flying toys counteract the turning force in a different way. They have two or more rotors spinning in opposite directions. The Boeing [[Wikipedia:Boeing_CH-47_Chinook|Chinook]] is an example. Some helicopters and many toys have two counter-rotating rotors on the same spindle. Quadcopters have 4 rotors but you can have any number, provided its an even number, and provided you make half of them spin one way and the other half spin the other way in order to balance out the twisting force.<br />
<br />
===Controls===<br />
A great advantage of having multiple rotors is that you can very simply manoeuvre your drone by deliberately unbalancing the rotors slightly. Applying a little more power to the two rear rotors of a quadcopter causes it to tip forward and so start moving forward. You can do the same with the rear two to make it move backwards, or two side rotors to make it move sideways. Equally, you can apply slightly more power to the two clockwise rotors to unbalance the twisting forces and make it turn anticlockwise, or vice versa. This is known as yaw.<br />
<br />
A hand-held controller with two joysticks is normally provided. Typically one controls forwards, backwards and sideways motion, and the other the overall power and yaw. A radio link transmits commands to the device.<br />
<br />
Model helicopters have two concentric counter-rotating rotors. Yaw is achieved by increasing the power to one and decreasing it to the other. A small propeller on the tail pointing upwards (unlike nearly all full size helicopters) tips the craft forwards or backwards to control the motion.<br />
<br />
You may come across a flying toy simply consisting of a ball with a pair of counter-rotating rotors. An infra-red sensor in the bottom detects the proximity of the ground and boosts the power to keep it airborne.<br />
<br />
The more sophisticated quadcopters and drones have a variety of sensors. A camera is common, which may record to an SDCard or transmit real-time video to the controller or a smartphone app. An air pressure sensor allows it to roughly maintain a given height, making it quite a lot easier to control. There may be a magnetometer to enable it to maintain a given magnetic compass heading, or a proximity sensor to enale it to make an automatic soft landing. A GPS module may be included, allowing it to follow a predetermined path or to automatically return to base. A variety of sensors may be included to implement a "follow me" function to film your sports activity.<br />
<br />
==Fault-finding==<br />
Common faults are physical breakages, unstable flight, and low power. Spares for the more popular models are availble from FarEastern suppliers such as [https://www.aliexpress.com/ AliExpress] or [https://www.banggood.com/ Banggood] and through eBay shops, if not locally.<br />
<br />
===Breakages and Mechanical Faults===<br />
Crashes are common, especially amongst toys and in the hands of youngsters, and these can lead to breakages. Read the instructions carefully and make sure you know how to kill the rotors dead in the event of a crash.<br />
<br />
Cheap ones are often so light that they can fall out of the sky with relative impunity, but if the rotors continue to receive power after becoming entangled or jammed, then damage may result.<br />
<br />
It may be possible to repair damage to a plastic shell with 2-part [[Sticky_Stuff#Epoxy|epoxy glue]].<br />
<br />
Often a set of spare rotor blades and rotor guards are provided, and for the more popular brands, spares are easily obtained. In fact the smaller rotors are fairly indestructible but may simply be a push-fit on the motor spindle. In a crash, they can sometimes come off and get lost. The clockwise and counter-clockwise rotors should be easily distinguisahble, for example marked A and B. Make sure you relace an A with an A or a B with a B, or it will be impossible to fly.<br />
<br />
If the problem is unstable flight, try flicking each rotor in turn. They should all spin equally freely. If not, this is likely to be the cause of the problem.<br />
<br />
Hairs can get tangled around the spindle between a rotor and its motor, causing additional friction and loss of control. A magnifying glass and a pair of tweezers may be helpful in removing it, but this will get difficult if it gets into the motor bearing.<br />
<br />
If the quadcopter has been disassembled (or has never flown well) there could be something else rubbing on a spindle. For example, there might be a rubber boot over each end of the motor to make it fit snugly in its housing, and this could be rubbing against the spindle if not correctly fitted.<br />
<br />
In some quadcopters the rotors are driven directly from the motor spindles whereas in others they are driven via a pair of gears to reduce the speed of rotation. Check that the gears are undamaged, clean and free of anything which might obstruct them.<br />
<br />
==Legal==<br />
Legal restrictions on the use of airborne devices such as drones will vary from one country to another.<br />
*In the UK you need a licence if your device is over 250g. See [https://www.gov.uk/government/news/drones-are-you-flying-yours-safely-and-legally Drones: how to fly them safely and legally].<br />
<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Quadcopters_and_drones&diff=3589Quadcopters and drones2020-06-25T20:57:02Z<p>Pleriche: Filled out Basic Principles</p>
<hr />
<div>This is currently a skeleton page. Please help by adding your contributions either here or in the associated Discussion page.<br />
<br />
This page will cover flying toys as well as larger and more serious drones.<br />
<br />
==Summary==<br />
In recent years, drones, both amateur and professional, and flying toys of various kinds have been made possible at reasonable cost by the availability of lithium batteries with a high power to weight ratio, and cheap control electronics and sensors. Particularly with toys, damaging crashes are common, but other faults may also arise.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Be sure you know how to fly your device safely. Rotating propeller blades can be very dangerous, especially the larger ones.<br />
::There are strict laws in many territories governing the use of drones and quadcopters, as well as radio controlled model aircraft of all types. See [[#Legal|Legal]] below.<br />
<br />
==Basic Principles==<br />
===Aerodynamic Principles===<br />
The idea of a machine which screws itself into the air dates back to Leonardo da Vinci in 1493, but it was another 450 years before the first practical helicopter took to the air.<br />
<br />
Unfortunately for Leonardo, Sir Isaac Newton had yet to formulate his Laws of Motion (published only in 1687). According to his 3rd law (action and reaction are equal and opposite), in forcing its rotor blades to turn against air resistance, the engine of a helicopter necessarily applies and equal and opposite turning force on the aircraft's body. So nearly all helicopters have a tail rotor to counteract this turning force. If a helicopter looses its tail rotor it spins out of control - the chances of surviving such an accident are very slim indeed.<br />
<br />
Just a few helicopters and nearly all drones and flying toys counteract the turning force in a different way. They have two or more rotors spinning in opposite directions. The Boeing [[Wikipedia:Boeing_CH-47_Chinook|Chinook]] is an example. Some helicopters and many toys have two counter-rotating rotors on the same spindle. Quadcopters have 4 rotors but you can have any number, provided its an even number, and provided you make half of them spin one way and the other half spin the other way in order to balance out the twisting force.<br />
<br />
===Controls===<br />
A great advantage of having multiple rotors is that you can very simply manoeuvre your drone by deliberately unbalancing the rotors slightly. Applying a little more power to the two rear rotors of a quadcopter causes it to tip forward and so start moving forward. You can do the same with the rear two to make it move backwards, or two side rotors to make it move sideways. Equally, you can apply slightly more power to the two clockwise rotors to unbalance the twisting forces and make it turn anticlockwise, or vice versa. This is known as yaw.<br />
<br />
A hand-held controller with two joysticks is normally provided. Typically one controls forwards, backwards and sideways motion, and the other the overall power and yaw. A radio link transmits commands to the device.<br />
<br />
Model helicopters have two concentric counter-rotating rotors. Yaw is achieved by increasing the power to one and decreasing it to the other. A small propeller on the tail pointing upwards (unlike nearly all full size helicopters) tips the craft forwards or backwards to control the motion.<br />
<br />
You may come across a flying toy simply consisting of a ball with a pair of counter-rotating rotors. An infra-red sensor in the bottom detects the proximity of the ground and boosts the power to keep it airborne.<br />
<br />
The more sophisticated quadcopters and drones have a variety of sensors. A camera is common, which may record to an SDCard or transmit real-time video to the controller or a smartphone app. An air pressure sensor allows it to roughly maintain a given height, making it quite a lot easier to control. There may be a magnetometer to enable it to maintain a given magnetic compass heading, or a proximity sensor to enale it to make an automatic soft landing. A GPS module may be included, allowing it to follow a predetermined path or to automatically return to base. A variety of sensors may be included to implement a "follow me" function to film your sports activity.<br />
<br />
==Fault-finding==<br />
<br />
<br />
==Legal==<br />
Legal restrictions on the use of airborne devices such as drones will vary from one country to another.<br />
*In the UK you need a licence if your device is over 250g. See [https://www.gov.uk/government/news/drones-are-you-flying-yours-safely-and-legally Drones: how to fly them safely and legally].<br />
<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Main_Page&diff=3588Main Page2020-06-25T20:13:17Z<p>Pleriche: Tony's changes undone. We can move Lightweight Browsers to the Software section when we at least have a skeleton page and some prospect of it being completed, but for now its proper place is under Wanted Pages.</p>
<hr />
<div><div class="welcome-header"><br />
Welcome to the Restart Wiki!<br />
</div><br />
<br />
<div class="welcome-text">This is a place where those of us in the Restart community with experience and skills in mending appliances and gadgets can share them with those who are starting out, or whose own knowledge lies in different areas.</div><br />
<br />
[[File:Blue_obj@2x.png|class=responsive-image]]<br />
<br />
'''What it isn't:''' It isn't going to show you how to fix a particular make and model of device, which we leave to the various fix-it sites and many disassembly videos. Here, we concentrate on basic and widely applicable principles. You can also get help with a particular device on Twitter or Instagram by tagging @RestartProject.<br />
<br />
'''Who it's for:''' It's aimed at anyone with a curiosity about how things work and how to fix them. No prior knowledge is assumed. In the spirit of sharing knowledge as widely as possible, everyone is welcome to read it. To contribute, just become a volunteer Restarter in your community and [http://therestartproject.org/contact/ contact us].<br />
<br />
Like any wiki, this one is work-in-progress. Pages referenced below in red don't yet exist but are projected.<br />
<br />
[[File:CC-BY-SA icon.svg|100px|right]]If you wish to reuse anything here, you are welcome do so under the terms of the Creative Commons ShareAlike Licence 4.0.<br />
<br />
To find out more about the work we do, and our vision of changing the world's relationship with electronics, please visit us at [https://therestartproject.org The Restart Project] homepage.<br />
<br />
==General Topics==<br />
* [[Scared to Repair?]] Some useful tips for complete beginners.<br />
* [[How to search]] - Tips on how to search for useful material.<br />
* [[Resources]] - Good sites for fixit or disassemble guides, service manuals etc.<br />
* [[Diagnosing faults]] - Common processes for troubleshooting.<br />
* [[Case Studies]] - Our favourite Famous Fixes in which we learned something new, or which nicely demonstrated a diagnostic or fixing principle.<br />
* [[Finding a reliable professional]] - best practices and some London examples.<br />
===Glossary of Terms===<br />
* [[Glossary]] - explanations of all the technical terms used in this wiki (and some more).<br />
<br />
===Repairing with others===<br />
* Thinking of running your own Restart Party? [http://therestartproject.org/restartparty/ All you need] is here.<br />
* [[Tools]] - Building a toolkit for community repair events.<br />
* [[Restarter Safety Guidelines]] - Safety instructions to be adhered to at all Restart Parties.<br />
* [[Measuring impact]].<br />
<br />
==Techniques, Skills and Tools==<br />
===Some really basic skills===<br />
* [[Water damage]] - the best (and worst) ways to rescue your gadget.<br />
* How to wire a mains plug - this [https://www.wikihow.com/Wire-a-UK-Plug step by step guide] shows you simply and with pictures.<br />
* [[How to drive screws like a pro]] - Using a screwdriver is easy but using it properly may not be obvious.<br />
* [[Types of screw head and screwdriver]] - Recognise even the more unusual types of screw so you can use the right screwdriver.<br />
* [[Rescuing Damaged Screws]] - What to do if the screw head is damaged.<br />
* [[How to use a multimeter]] - the most useful addition to your toolbox after screwdrivers etc.<br />
* [[Magnifiers and Inspection Aids]] - You can't fix what you can't see. How to see better.<br />
<br />
===Soldering skills===<br />
* [https://www.kitronik.co.uk/blog/soldering-school-kitronik-university A Guide to Soldering] from [https://www.kitronik.co.uk Kitronic] is a complete guide to the art, including video demonstrations.<br />
* [https://www.techwillsaveus.com/resources/learn-to-solder/ How to solder] is a more light-hearted and amusing but nevertheless informative resource from [https://www.techwillsaveus.com Technology Will Save Us]. (You don't need an expensive soldering iron though - it just makes it a little bit easier.)<br />
* [[Surface mount soldering]] - What you can do and how to do it by supplementing the tools you probably already have with a few inexpensive extras.<br />
<br />
===Fixing skills===<br />
* [[Connectors]] - Various different types you will meet, and how to disconnect and reconnect them.<br />
* [[Connecting and joining wires]] - different methods for different situations.<br />
* [[Sticky Stuff]] - How to stick things back together when they break.<br />
<br />
===Staying safe===<br />
* [[PAT testing]] survival guide.<br />
* [[Personal Protective Equipment]] - keeping yourself safe.<br />
* [[Electrostatic Discharge Precautions]] - how not to fry your gadgets with static.<br />
<br />
==Understanding how stuff works (or doesn't)==<br />
A [https://www.youtube.com/watch?v=kyHy3uFJrj0 Restarters' Training Session] makes an easy introduction to the following sections down to and including Electronic Components. It consists of a presentation with audio commentary, lasting around 50 minutes.<br />
* [[Electric circuits, volts amps watts and ohms]] - what every Restarter should know.<br />
* [[AC and DC]] - what's the deal?<br />
* Electronic components - recognition, failure modes and testing:<br />
** [[Basic electronic components]] - Resistors, capacitors, inductors and transformers, and quartz crystals.<br />
** [[Active components]] - Diodes and rectifiers, transistors, and integrated circuits (ICs).<br />
** [[Passive components]] - Switches, push-buttons and connectors.<br />
** [[Protection components]] - Various devices for over-voltage and over-current protection. Fuses are only the beginning!<br />
* [[Batteries]] - different types, shapes and sizes, what they're good for, how to buy them, use them and dispose of them.<br />
* [[Light bulbs]] - the several different types and their various shapes, sizes and bases, all explained.<br />
* [[Electric motors]] - different types, how to recognise them, test them and maybe fix them.<br />
* [[Power supplies]] - how they work, what can go wrong, and how to test and fix them.<br />
* [[How radios work]] - basic theory to help you understand what might be wrong when you can't see it with your own eyes.<br />
* [[All about SSDs]] - everything you always wanted to know but were afraid to ask.<br />
<br />
[http://www.learnabout-electronics.org/ Learn About Electronics] is an excellent site if you'd like a different view of the basics, or if you'd like to go deeper.<br />
<br />
==Computers and home office==<br />
===Software===<br />
* How to deal with a [[slow laptop]] - mainly focussed on Windows.<br />
* [[Windows miscellaneous]].<br />
* [[Be Your Own Security Expert]] - helping people stay secure.<br />
* How to speed up a [[slow OS X computer]].<br />
* [[Apple miscellaneous]] including OS X and Macs.<br />
* [[Linux migration]] - Choosing a distro, and throwing Windows out of computers.<br />
* [[CD/USB bootable tools]] - many of them applicable whatever your operating system.<br />
* [[Disk Wipe Utilities]] - How to securely erase all sensitive data from an old computer, and why you should never skip doing so.<br />
* [[UEFI and GPT]] - Making sense of UEFI, which supercedes the BIOS in all computers since around 2011, and the GPT disk structure which goes with it.<br />
<br />
===Computer Hardware===<br />
* [[Yes, you can fix your laptop!]]<br />
* [[Laptop power problems]].<br />
* [[Clean up! Cool down!]] - dealing with dust build-up and overheating in laptop and desktop computers.<br />
* [[Advanced hard disk tools]] - and the simpler ones too. Where to turn when the data is in danger.<br />
* [[SSD Migration and Troubleshooting]] - Solid State Disks: everything you might need to know.<br />
<br />
<br />
===Peripherals===<br />
* Troubleshooting [[inkjet printers]].<br />
* Data [[Projectors]].<br />
* [[Document scanners]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Flat screen TVs and monitors|Flat screen computer monitors (and TVs)]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
<br />
==Electronic gadgets==<br />
<br />
===Feature phones===<br />
===Smartphones and tablets (except Apple)===<br />
* [[Tablets and smartphones - common problems]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Android Tips and Tricks]].<br />
* Installing a [[Custom ROMs|Custom ROM]] may enable you to extend the useful life of your phone or tablet.<br />
<br />
===iPods, iPhones, iPads===<br />
* Summary of [[Summary iPhone iPad and iPod repair|iPhone, iPad, iPod and tablet repairs]].<br />
<br />
===Headphones===<br />
* How to mend [[Headphones]].<br />
<br />
===Cameras===<br />
* [[Compact cameras]].<br />
<br />
===Satnavs===<br />
<br />
===Toys===<br />
* [[Quadcopters and drones]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
<br />
==Home entertainment==<br />
<br />
* [[Audio equipment]].<br />
* [[CD and DVD players]].<br />
* [[Flat screen TVs and monitors]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Portable radios]].<br />
* [[Sicilian screwdriver]] - slightly more entertaining than the regular sort. (Just for fun!)<br />
<br />
==Household and Kitchen items==<br />
<br />
* [[Carbon-based gadgets]] - all you need to know. (Just for fun!)<br />
* [[Clocks]] - Plenty about the theory, but can you contribute any experience of fixing them?<br />
* [[Digital weighing scales]] - how they work and what might go wrong.<br />
* [[Fans and fan heaters]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Garden power tools]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Grooming products]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Kettles and Electric Urns]] - how they work and the possibilities for fixing.<br />
* [[Microwave Ovens]] (This page contains IMPORTANT SAFETY WARNINGS.)<br />
* [[Mixers, blenders and coffee grinders]].<br />
* [[Paper shredders]] - how they work, and the mechanical and electrical problems they can suffer from.<br />
* [[Sewing machines]] demystified. Trouble-shooting, care and maintenance.<br />
* [[Steam Irons]].<br />
* [[Table lamps]], desk lamps and floor-standing lamps.<br />
* [[Toasters]].<br />
* [[Vacuum cleaners]].<br />
<br />
==Wanted Pages==<br />
<br />
In addition to the pages marked above in red as "<span style="color:red">skeleton pages</span>" we have identified the following subjects that we'd like to cover.<br />
<br />
Could you contribute your knowledge and experience, even if it's only notes that someone else can refine and turn into a properly organised and formatted page? (Skeleton pages have an associated "Discussion" page where you can add any half-baked thoughts and ideas.)<br />
<div style="color:red"><br />
* Alternatives to iOS for older Apple devices.<br />
* Using a lightweight browser to extend the life of a device mainly used for web and email.<br />
* Satnavs.<br />
</div><br />
(You can add to this list if you like!)<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Main_Page&diff=3587Main Page2020-06-25T19:59:50Z<p>Pleriche: </p>
<hr />
<div><div class="welcome-header"><br />
Welcome to the Restart Wiki!<br />
</div><br />
<br />
<div class="welcome-text">This is a place where those of us in the Restart community with experience and skills in mending appliances and gadgets can share them with those who are starting out, or whose own knowledge lies in different areas.</div><br />
<br />
[[File:Blue_obj@2x.png|class=responsive-image]]<br />
<br />
'''What it isn't:''' It isn't going to show you how to fix a particular make and model of device, which we leave to the various fix-it sites and many disassembly videos. Here, we concentrate on basic and widely applicable principles. You can also get help with a particular device on Twitter or Instagram by tagging @RestartProject.<br />
<br />
'''Who it's for:''' It's aimed at anyone with a curiosity about how things work and how to fix them. No prior knowledge is assumed. In the spirit of sharing knowledge as widely as possible, everyone is welcome to read it. To contribute, just become a volunteer Restarter in your community and [http://therestartproject.org/contact/ contact us].<br />
<br />
Like any wiki, this one is work-in-progress. Pages referenced below in red don't yet exist but are projected.<br />
<br />
[[File:CC-BY-SA icon.svg|100px|right]]If you wish to reuse anything here, you are welcome do so under the terms of the Creative Commons ShareAlike Licence 4.0.<br />
<br />
To find out more about the work we do, and our vision of changing the world's relationship with electronics, please visit us at [https://therestartproject.org The Restart Project] homepage.<br />
<br />
==General Topics==<br />
* [[Scared to Repair?]] Some useful tips for complete beginners.<br />
* [[How to search]] - Tips on how to search for useful material.<br />
* [[Resources]] - Good sites for fixit or disassemble guides, service manuals etc.<br />
* [[Diagnosing faults]] - Common processes for troubleshooting.<br />
* [[Case Studies]] - Our favourite Famous Fixes in which we learned something new, or which nicely demonstrated a diagnostic or fixing principle.<br />
* [[Finding a reliable professional]] - best practices and some London examples.<br />
===Glossary of Terms===<br />
* [[Glossary]] - explanations of all the technical terms used in this wiki (and some more).<br />
<br />
===Repairing with others===<br />
* Thinking of running your own Restart Party? [http://therestartproject.org/restartparty/ All you need] is here.<br />
* [[Tools]] - Building a toolkit for community repair events.<br />
* [[Restarter Safety Guidelines]] - Safety instructions to be adhered to at all Restart Parties.<br />
* [[Measuring impact]].<br />
<br />
==Techniques, Skills and Tools==<br />
===Some really basic skills===<br />
* [[Water damage]] - the best (and worst) ways to rescue your gadget.<br />
* How to wire a mains plug - this [https://www.wikihow.com/Wire-a-UK-Plug step by step guide] shows you simply and with pictures.<br />
* [[How to drive screws like a pro]] - Using a screwdriver is easy but using it properly may not be obvious.<br />
* [[Types of screw head and screwdriver]] - Recognise even the more unusual types of screw so you can use the right screwdriver.<br />
* [[Rescuing Damaged Screws]] - What to do if the screw head is damaged.<br />
* [[How to use a multimeter]] - the most useful addition to your toolbox after screwdrivers etc.<br />
* [[Magnifiers and Inspection Aids]] - You can't fix what you can't see. How to see better.<br />
<br />
===Soldering skills===<br />
* [https://www.kitronik.co.uk/blog/soldering-school-kitronik-university A Guide to Soldering] from [https://www.kitronik.co.uk Kitronic] is a complete guide to the art, including video demonstrations.<br />
* [https://www.techwillsaveus.com/resources/learn-to-solder/ How to solder] is a more light-hearted and amusing but nevertheless informative resource from [https://www.techwillsaveus.com Technology Will Save Us]. (You don't need an expensive soldering iron though - it just makes it a little bit easier.)<br />
* [[Surface mount soldering]] - What you can do and how to do it by supplementing the tools you probably already have with a few inexpensive extras.<br />
<br />
===Fixing skills===<br />
* [[Connectors]] - Various different types you will meet, and how to disconnect and reconnect them.<br />
* [[Connecting and joining wires]] - different methods for different situations.<br />
* [[Sticky Stuff]] - How to stick things back together when they break.<br />
<br />
===Staying safe===<br />
* [[PAT testing]] survival guide.<br />
* [[Personal Protective Equipment]] - keeping yourself safe.<br />
* [[Electrostatic Discharge Precautions]] - how not to fry your gadgets with static.<br />
<br />
==Understanding how stuff works (or doesn't)==<br />
A [https://www.youtube.com/watch?v=kyHy3uFJrj0 Restarters' Training Session] makes an easy introduction to the following sections down to and including Electronic Components. It consists of a presentation with audio commentary, lasting around 50 minutes.<br />
* [[Electric circuits, volts amps watts and ohms]] - what every Restarter should know.<br />
* [[AC and DC]] - what's the deal?<br />
* Electronic components - recognition, failure modes and testing:<br />
** [[Basic electronic components]] - Resistors, capacitors, inductors and transformers, and quartz crystals.<br />
** [[Active components]] - Diodes and rectifiers, transistors, and integrated circuits (ICs).<br />
** [[Passive components]] - Switches, push-buttons and connectors.<br />
** [[Protection components]] - Various devices for over-voltage and over-current protection. Fuses are only the beginning!<br />
* [[Batteries]] - different types, shapes and sizes, what they're good for, how to buy them, use them and dispose of them.<br />
* [[Light bulbs]] - the several different types and their various shapes, sizes and bases, all explained.<br />
* [[Electric motors]] - different types, how to recognise them, test them and maybe fix them.<br />
* [[Power supplies]] - how they work, what can go wrong, and how to test and fix them.<br />
* [[How radios work]] - basic theory to help you understand what might be wrong when you can't see it with your own eyes.<br />
* [[All about SSDs]] - everything you always wanted to know but were afraid to ask.<br />
<br />
[http://www.learnabout-electronics.org/ Learn About Electronics] is an excellent site if you'd like a different view of the basics, or if you'd like to go deeper.<br />
<br />
==Computers and home office==<br />
===Software===<br />
* How to deal with a [[slow laptop]] - mainly focussed on Windows.<br />
* [[Using a lightweight browser to extend the life of a device mainly used for web and email]]<br />
* [[Windows miscellaneous]].<br />
* [[Be Your Own Security Expert]] - helping people stay secure.<br />
* How to speed up a [[slow OS X computer]].<br />
* [[Apple miscellaneous]] including OS X and Macs.<br />
* [[Linux migration]] - Choosing a distro, and throwing Windows out of computers.<br />
* [[CD/USB bootable tools]] - many of them applicable whatever your operating system.<br />
* [[Disk Wipe Utilities]] - How to securely erase all sensitive data from an old computer, and why you should never skip doing so.<br />
* [[UEFI and GPT]] - Making sense of UEFI, which supercedes the BIOS in all computers since around 2011, and the GPT disk structure which goes with it.<br />
<br />
===Computer Hardware===<br />
* [[Yes, you can fix your laptop!]]<br />
* [[Laptop power problems]].<br />
* [[Clean up! Cool down!]] - dealing with dust build-up and overheating in laptop and desktop computers.<br />
* [[Advanced hard disk tools]] - and the simpler ones too. Where to turn when the data is in danger.<br />
* [[SSD Migration and Troubleshooting]] - Solid State Disks: everything you might need to know.<br />
<br />
<br />
===Peripherals===<br />
* Troubleshooting [[inkjet printers]].<br />
* Data [[Projectors]].<br />
* [[Document scanners]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Flat screen TVs and monitors|Flat screen computer monitors (and TVs)]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
<br />
==Electronic gadgets==<br />
<br />
===Feature phones===<br />
===Smartphones and tablets (except Apple)===<br />
* [[Tablets and smartphones - common problems]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Android Tips and Tricks]].<br />
* Installing a [[Custom ROMs|Custom ROM]] may enable you to extend the useful life of your phone or tablet.<br />
<br />
===iPods, iPhones, iPads===<br />
* Summary of [[Summary iPhone iPad and iPod repair|iPhone, iPad, iPod and tablet repairs]].<br />
<br />
===Headphones===<br />
* How to mend [[Headphones]].<br />
<br />
===Cameras===<br />
* [[Compact cameras]].<br />
<br />
===Satnavs===<br />
<br />
===Toys===<br />
* [[Quadcopters and drones]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
<br />
==Home entertainment==<br />
<br />
* [[Audio equipment]].<br />
* [[CD and DVD players]].<br />
* [[Flat screen TVs and monitors]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Portable radios]].<br />
* [[Sicilian screwdriver]] - slightly more entertaining than the regular sort. (Just for fun!)<br />
<br />
==Household and Kitchen items==<br />
<br />
* [[Carbon-based gadgets]] - all you need to know. (Just for fun!)<br />
* [[Clocks]] - Plenty about the theory, but can you contribute any experience of fixing them?<br />
* [[Digital weighing scales]] - how they work and what might go wrong.<br />
* [[Fans and fan heaters]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Garden power tools]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Grooming products]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Kettles and Electric Urns]] - how they work and the possibilities for fixing.<br />
* [[Microwave Ovens]] (This page contains IMPORTANT SAFETY WARNINGS.)<br />
* [[Mixers, blenders and coffee grinders]].<br />
* [[Paper shredders]] - how they work, and the mechanical and electrical problems they can suffer from.<br />
* [[Sewing machines]] demystified. Trouble-shooting, care and maintenance.<br />
* [[Steam Irons]].<br />
* [[Table lamps]], desk lamps and floor-standing lamps.<br />
* [[Toasters]].<br />
* [[Vacuum cleaners]].<br />
<br />
==Wanted Pages==<br />
<br />
In addition to the pages marked above in red as "<span style="color:red">skeleton pages</span>" we have identified the following subjects that we'd like to cover.<br />
<br />
Could you contribute your knowledge and experience, even if it's only notes that someone else can refine and turn into a properly organised and formatted page? (Skeleton pages have an associated "Discussion" page where you can add any half-baked thoughts and ideas.)<br />
<div style="color:red"><br />
* Alternatives to iOS for older Apple devices.<br />
* Satnavs.<br />
</div><br />
(You can add to this list if you like!)<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Spare_parts&diff=3575Spare parts2020-06-19T11:03:13Z<p>Pleriche: </p>
<hr />
<div>Spare parts are commonly needed when repairing electric or electronic items. Here we discuss which types of spare parts there are and how they can be sourced. <br />
<br />
<br />
== Types of Spare Parts ==<br />
<br />
<br />
=== Original Parts ===<br />
<br />
Original parts are made and distributed by the manufacturers themselves. Buying an original part gives you the certainty that it will fit the device. However, manufacturers often don’t produce spare parts, or limit availability to authorised repairers.<br />
<br />
<br />
=== Third Party Parts ===<br />
<br />
Where original spare parts aren’t available, third party ones often are if there is demand for them. Smartphone screens are a good example for this. But with this often comes some push back from manufacturers who want to restrict independent and third party repairers if they see them as a threat to their business.<br />
<br />
Some third party spare parts are in fact identical to the genuine article and even come off the same production line. For example, a smartphone screen or battery manufacturer may simply continue a manufacturing run after satisfying the original order. However, the provenance of a spare part may be impossible to ascertain without a visit to the Far East, which in fact some reputable parts suppliers may actually have undertaken!<br />
<br />
A lack of accountability can be a problem when buying third party parts, as it can be difficult to determine in advance that a spare part will be fit for purpose. Depending on where you buy, warranty and refund options may be limited.<br />
<br />
<br />
=== Refurbished and Remanufactured Parts ===<br />
<br />
Refurbished parts are spare parts that have been extracted from a used device and were repaired to be functional again. Note: "Refurbished" is not a protected term, anyone can use it and it can mean a variety of things. "Remanufactured" however is a protected term which means that the product meets all specifications of the original new product. With refurbished parts it can be difficult to tell what you get. Some parts might be refurbished in an unreliable way (e.g. reflowing a chip on the motherboard), others might have required only small repairs like a software reconfiguration and might work very well.<br />
When buying refurbished parts, it is good to look for a long warranty period and to buy from a reputable and accountable manufacturer.<br />
<br />
<br />
=== Salvaging Parts ===<br />
<br />
From some devices it is easier to salvage parts than from others. E.g. desktop PCs are designed to be more modular for the end user and individual parts are designed to widely adopted standards. So usually individual working parts from a desktop PC can be used as spare parts. In other devices, end user modification or salvaging is not promoted and reusing parts is more difficult, as they are more often bespoke for that particular device. For example, many televisions would have their own unique power supply and motherboard that could only be directly used again in that same model of TV.<br />
<br />
Salvaged spare parts will have individual discrete components that can be used again in other devices, such as resistors, capacitors, diodes or transistors, though individually, few of these would be worth salvaging except by an electronics hobbyist.<br />
<br />
See below for an overview of spare parts and where to find them. <br />
<br />
<br />
<br />
== Where to buy ==<br />
<br />
<br />
=== Buying from manufacturer ===<br />
<br />
Original spare parts will often be available directly via the manufacturer, but at a premium price. However there is no legal regulation that requires spare parts to be available to the public - that’s one of the reasons why we need a Right to Repair. <br />
<br />
<br />
=== Spare parts suppliers ===<br />
<br />
Several online shops have specialised in selling spare parts, both from the original manufacturers and from third party suppliers. The advantage of these online shops is that they often provide a warranty and good customer service. However especially for older or less common devices it might be difficult to find the desired spare part here. <br />
<br />
<br />
=== Buying from eBay ===<br />
<br />
eBay can be a good source of spare parts which are not available from the original supplier, and sometimes this is the only way to source a particular part. It is hard for sellers to maintain a good eBay reputation as their customer service usually favours the buyer side in any dispute and seller accounts can get banned after a few incidents. So most sellers will offer good products in order to receive good feedback.<br />
<br />
However, as a wide range of people sell on eBay, some issues are common: items might be mislabelled or falsely claimed to be genuine, they might not meet EU/UK standards or they might have not been tested (e.g. when a circuit board has been taken from a cracked TV). <br />
<br />
<br />
<br />
== Potential issues and how to overcome them ==<br />
<br />
=== Identifying fakes ===<br />
<br />
When buying something labelled as an original spare part, always ask yourself: would the manufacturer still sell that item? It is unlikely that manufacturers provide spare parts for much longer than they are required to. This should not always be an excluding criterion though - it might be that the seller stocked up on the spare part himself when they were still commonly available. Surprisingly cheap prices can also be a warning sign that the piece might be fake.<br />
<br />
It's especially important to beware of fakes where there may be safety issues. A good example is mains adapters, where inadequate insulation and isolation of the mains supply or underrated components may lead to electric shock or fire hazards.<br />
<br />
<br />
=== Software Locks ===<br />
<br />
Sometimes manufacturers place software locks on hardware, meaning that the device will only work with the components it originally came with. This stops repairers from using a component as a spare part in another device without illegally modifying the software. Manufacturers often claim security or safety reasons for this.<br />
<br />
Also, manufacturers might deliberately stop servicing or providing support for software on older devices, citing escalating support costs or enhanced safety or security, but also to encourage the end users to replace them. The real motivation may be difficult to untangle with an open mind. <br />
<br />
<br />
=== More things to consider when buying used ===<br />
<br />
Some parts are more affected by excessive use over time than others. In computers and games consoles, GPUs and CPUs will often fail after excessive use over time if they are not properly ventilated and thereby cooled. When buying such used parts, you often don’t know how much they have been used already. <br />
Moving/mechanical parts (e.g. hard drives, drive belts, switches) will often be the first to fail so when you buy them used, you don’t know how much lifetime they still have in them.<br />
<br />
BUT: If only second hand parts are available, don’t hold your breath - look for a returns policy and good seller feedback record.</div>Plerichehttps://wiki.restarters.net/index.php?title=Glossary:OEM&diff=3574Glossary:OEM2020-06-19T10:53:18Z<p>Pleriche: </p>
<hr />
<div>Original Equipment Manufacturer. A somewhat confusing term generally meaning a company which sells another company's manufactured goods under its own branding and with its own warranty. Also used of software, for a licence allowing a computer manufacturer to install the software on systems they build. (In fact, the manufacturer could be you, building a computer from standard parts.)</div>Plerichehttps://wiki.restarters.net/index.php?title=Main_Page&diff=3562Main Page2020-05-28T20:09:09Z<p>Pleriche: /* Household and Kitchen items */</p>
<hr />
<div><div class="welcome-header"><br />
Welcome to the Restart Wiki!<br />
</div><br />
<br />
<div class="welcome-text">This is a place where those of us in the Restart community with experience and skills in mending appliances and gadgets can share them with those who are starting out, or whose own knowledge lies in different areas.</div><br />
<br />
[[File:Blue_obj@2x.png|class=responsive-image]]<br />
<br />
'''What it isn't:''' It isn't going to show you how to fix a particular make and model of device, which we leave to the various fix-it sites and many disassembly videos. Here, we concentrate on basic and widely applicable principles. You can also get help with a particular device on Twitter or Instagram by tagging @RestartProject.<br />
<br />
'''Who it's for:''' It's aimed at anyone with a curiosity about how things work and how to fix them. No prior knowledge is assumed. In the spirit of sharing knowledge as widely as possible, everyone is welcome to read it. To contribute, just become a volunteer Restarter in your community and [http://therestartproject.org/contact/ contact us].<br />
<br />
Like any wiki, this one is work-in-progress. Pages referenced below in red don't yet exist but are projected.<br />
<br />
[[File:CC-BY-SA icon.svg|100px|right]]If you wish to reuse anything here, you are welcome do so under the terms of the Creative Commons ShareAlike Licence 4.0.<br />
<br />
To find out more about the work we do, and our vision of changing the world's relationship with electronics, please visit us at [https://therestartproject.org The Restart Project] homepage.<br />
<br />
==General Topics==<br />
* [[Scared to Repair?]] Some useful tips for complete beginners.<br />
* [[How to search]] - Tips on how to search for useful material.<br />
* [[Resources]] - Good sites for fixit or disassemble guides, service manuals etc.<br />
* [[Diagnosing faults]] - Common processes for troubleshooting.<br />
* [[Case Studies]] - Our favourite Famous Fixes in which we learned something new, or which nicely demonstrated a diagnostic or fixing principle.<br />
* [[Finding a reliable professional]] - best practices and some London examples.<br />
===Glossary of Terms===<br />
* [[Glossary]] - explanations of all the technical terms used in this wiki (and some more).<br />
<br />
===Repairing with others===<br />
* Thinking of running your own Restart Party? [http://therestartproject.org/restartparty/ All you need] is here.<br />
* [[Tools]] - Building a toolkit for community repair events.<br />
* [[Restarter Safety Guidelines]] - Safety instructions to be adhered to at all Restart Parties.<br />
* [[Measuring impact]].<br />
<br />
==Techniques, Skills and Tools==<br />
===Some really basic skills===<br />
* [[Water damage]] - the best (and worst) ways to rescue your gadget.<br />
* How to wire a mains plug - this [http://www.rospa.com/home-safety/uk/northern-ireland/electricity/plugs-fuses/wiring-plugs/ step by step guide] shows you simply and with pictures.<br />
* [[How to drive screws like a pro]] - Using a screwdriver is easy but using it properly may not be obvious.<br />
* [[Types of screw head and screwdriver]] - Recognise even the more unusual types of screw so you can use the right screwdriver.<br />
* [[Rescuing Damaged Screws]] - What to do if the screw head is damaged.<br />
* [[How to use a multimeter]] - the most useful addition to your toolbox after screwdrivers etc.<br />
* [[Magnifiers and Inspection Aids]] - You can't fix what you can't see. How to see better.<br />
<br />
===Soldering skills===<br />
* [https://www.kitronik.co.uk/blog/soldering-school-kitronik-university A Guide to Soldering] from [https://www.kitronik.co.uk Kitronic] is a complete guide to the art, including video demonstrations.<br />
* [https://www.techwillsaveus.com/resources/learn-to-solder/ How to solder] is a more light-hearted and amusing but nevertheless informative resource from [https://www.techwillsaveus.com Technology Will Save Us]. (You don't need an expensive soldering iron though - it just makes it a little bit easier.)<br />
* [[Surface mount soldering]] - What you can do and how to do it by supplementing the tools you probably already have with a few inexpensive extras.<br />
<br />
===Fixing skills===<br />
* [[Connectors]] - Various different types you will meet, and how to disconnect and reconnect them.<br />
* [[Connecting and joining wires]] - different methods for different situations.<br />
* [[Sticky Stuff]] - How to stick things back together when they break.<br />
<br />
===Staying safe===<br />
* [[PAT testing]] survival guide.<br />
* [[Personal Protective Equipment]] - keeping yourself safe.<br />
* [[Electrostatic Discharge Precautions]] - how not to fry your gadgets with static.<br />
<br />
==Understanding how stuff works (or doesn't)==<br />
A [https://www.youtube.com/watch?v=kyHy3uFJrj0 Restarters' Training Session] makes an easy introduction to the following sections down to and including Electronic Components. It consists of a presentation with audio commentary, lasting around 50 minutes.<br />
* [[Electric circuits, volts amps watts and ohms]] - what every Restarter should know.<br />
* [[AC and DC]] - what's the deal?<br />
* Electronic components - recognition, failure modes and testing:<br />
** [[Basic electronic components]] - Resistors, capacitors, inductors and transformers, and quartz crystals.<br />
** [[Active components]] - Diodes and rectifiers, transistors, and integrated circuits (ICs).<br />
** [[Passive components]] - Switches, push-buttons and connectors.<br />
** [[Protection components]] - Various devices for over-voltage and over-current protection. Fuses are only the beginning!<br />
* [[Batteries]] - different types, shapes and sizes, what they're good for, how to buy them, use them and dispose of them.<br />
* [[Light bulbs]] - the several different types and their various shapes, sizes and bases, all explained.<br />
* [[Electric motors]] - different types, how to recognise them, test them and maybe fix them.<br />
* [[Power supplies]] - how they work, what can go wrong, and how to test and fix them.<br />
* [[How radios work]] - basic theory to help you understand what might be wrong when you can't see it with your own eyes.<br />
* [[All about SSDs]] - everything you always wanted to know but were afraid to ask.<br />
<br />
[http://www.learnabout-electronics.org/ Learn About Electronics] is an excellent site if you'd like a different view of the basics, or if you'd like to go deeper.<br />
<br />
==Computers and home office==<br />
===Software===<br />
* How to deal with a [[slow laptop]] - mainly focussed on Windows.<br />
* [[Windows miscellaneous]].<br />
* [[Be Your Own Security Expert]] - helping people stay secure.<br />
* How to speed up a [[slow OS X computer]].<br />
* [[Apple miscellaneous]] including OS X and Macs.<br />
* [[Linux migration]] - Choosing a distro, and throwing Windows out of computers.<br />
* [[CD/USB bootable tools]] - many of them applicable whatever your operating system.<br />
* [[Disk Wipe Utilities]] - How to securely erase all sensitive data from an old computer, and why you should never skip doing so.<br />
* [[UEFI and GPT]] - Making sense of UEFI, which supercedes the BIOS in all computers since around 2011, and the GPT disk structure which goes with it.<br />
<br />
===Computer Hardware===<br />
* [[Yes, you can fix your laptop!]]<br />
* [[Laptop power problems]].<br />
* [[Clean up! Cool down!]] - dealing with dust build-up and overheating in laptop and desktop computers.<br />
* [[Advanced hard disk tools]] - and the simpler ones too. Where to turn when the data is in danger.<br />
* [[SSD Migration and Troubleshooting]] - Solid State Disks: everything you might need to know.<br />
<br />
<br />
===Peripherals===<br />
* Troubleshooting [[inkjet printers]].<br />
* Data [[Projectors]].<br />
* [[Document scanners]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Flat screen TVs and monitors|Flat screen computer monitors (and TVs)]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
<br />
==Electronic gadgets==<br />
<br />
===Feature phones===<br />
===Smartphones and tablets (except Apple)===<br />
* [[Tablets and smartphones - common problems]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Android Tips and Tricks]].<br />
* Installing a [[Custom ROMs|Custom ROM]] may enable you to extend the useful life of your phone or tablet.<br />
<br />
===iPods, iPhones, iPads===<br />
* Summary of [[Summary iPhone iPad and iPod repair|iPhone, iPad, iPod and tablet repairs]].<br />
<br />
===Headphones===<br />
* How to mend [[Headphones]].<br />
<br />
===Cameras===<br />
* [[Compact cameras]].<br />
<br />
===Satnavs===<br />
<br />
===Toys===<br />
* [[Quadcopters and drones]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
<br />
==Home entertainment==<br />
<br />
* [[Audio equipment]].<br />
* [[CD and DVD players]].<br />
* [[Flat screen TVs and monitors]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Portable radios]].<br />
* [[Sicilian screwdriver]] - slightly more entertaining than the regular sort. (Just for fun!)<br />
<br />
==Household and Kitchen items==<br />
<br />
* [[Carbon-based gadgets]] - all you need to know. (Just for fun!)<br />
* [[Clocks]] - Plenty about the theory, but can you contribute any experience of fixing them?<br />
* [[Digital weighing scales]] - how they work and what might go wrong.<br />
* [[Fans and fan heaters]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Garden power tools]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Grooming products]] - <span style="color:red">just a skeleton page for now. Can you help by fleshing it out?</span><br />
* [[Kettles and Electric Urns]] - how they work and the possibilities for fixing.<br />
* [[Microwave Ovens]] (This page contains IMPORTANT SAFETY WARNINGS.)<br />
* [[Mixers, blenders and coffee grinders]].<br />
* [[Paper shredders]] - how they work, and the mechanical and electrical problems they can suffer from.<br />
* [[Sewing machines]] demystified. Trouble-shooting, care and maintenance.<br />
* [[Steam Irons]].<br />
* [[Table lamps]], desk lamps and floor-standing lamps.<br />
* [[Toasters]].<br />
* [[Vacuum cleaners]].<br />
<br />
==Wanted Pages==<br />
<br />
In addition to the pages marked above in red as "<span style="color:red">skeleton pages</span>" we have identified the following subjects that we'd like to cover.<br />
<br />
Could contribute your knowledge and experience, even if it's only notes that someone else can refine and turn into a properly organised and formatted page? (Skeleton pages have an associated "Discussion" page where you can add any half-baked thoughts and ideas.)<br />
<div style="color:red"><br />
* Using a lightweight browser to extend the life of a device mainly used for web and email.<br />
* Alternatives to iOS for older Apple devices.<br />
* Satnavs.<br />
</div><br />
(You can add to this list if you like!)<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Glossary:Electrolytic_Capacitor&diff=3561Glossary:Electrolytic Capacitor2020-05-28T20:07:03Z<p>Pleriche: </p>
<hr />
<div>An electrolytic capacitor is a type of [[Glossary:Capacitor|capacitor]] which employs an electro-chemical process to achieve a high value of capacitance. However, their failure rate is relatively high - see [[Basic electronic components#Capacitors|Capacitors]] in the Wiki.</div>Plerichehttps://wiki.restarters.net/index.php?title=Electric_motors&diff=3560Electric motors2020-05-28T20:01:30Z<p>Pleriche: </p>
<hr />
<div>This page covers electric motors of various types, how to identify them and understand their common failure modes, and how to test them.<br />
<br />
==Summary==<br />
Many devices and appliances contain electric motors. This page will help you understand how they work, what can go wrong, and maybe how to fix them.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Motors in domestic appliances can be quite powerful, and along with associated gears and mechanisms, can cause injury. As with all mains electrical appliances, it is essential to unplug them before starting work. The appliance should be [[PAT testing|PAT tested]] both before and after any disassembly or repair is attempted.<br />
<br />
==Types of Motor==<br />
<br />
There are many types of electric motor but nearly all fall into three main types. They all have two main components:<br />
* The Rotor - the bit that spins, and<br />
* The Stator - the bit that doesn't spin.<br />
They all rely on '''electromagnetism'''. When an electric current flows through a coil of wire it creates a magnetic field. The coil is usually wound around an iron core which then gets magnetised, greatly increasing the magnetism.<br />
<br />
===DC and Universal (AC/DC) Motors===<br />
[[File:Img_1924a.jpg|180px|thumb|left|A universal motor, dismantled.]]<br />
[[File:Img_1926a.jpg|180px|thumb|right|A universal motor showing the rotor with the commutator.]]<br />
[[File:Img_1928a.jpg|180px|thumb|right|A universal motor showing the stator with the brushes at the far end.]]<br />
The stator is a permanent magnet or an electromagnet.<br />
<br />
In the simplest toy motors, the rotor is another coil, or a whole series of coils in all practical motors, wound around a laminated iron core.<br />
<br />
A pair of carbon '''brushes''' supply current to the rotor via a '''commutator''', which continually switches the current in the rotor into whichever coils are at right angles to the stator coil at any given moment. This produces a continuous turning force.<br />
<br />
In an '''electronically commutated''' or '''brushless''' motor, the rotor is often a permanent magnet. Electronic circuits sense the rotor position and continually switch the current in a series of stator coils in order to turn the rotor. This avoids the need for any electrical connection to the rotor and so increases the reliability.<br />
<br />
[[Glossary:DC|DC]] and universal motors work equally well as dynamos, and generate a [[Glossary:Volt|voltage]] which opposes the applied voltage. This is known as a "back emf (electro-motive force)". Under a light load, these motors speed up until they are generating nearly as much voltage as is applied. Consequently, it's easy to vary the speed just by varying the applied voltage.<br />
<br />
The commutator and brushes (except in electrically commutated motors) are subject to wear and can produce sparks. Such motors are therefore not used where the highest reliability is required or where there is a risk of fire or explosion from flammable gasses.<br />
<br />
The dynamo effect is at a minimum when the motor first starts and before it reaches full speed. This allows the motor to draw a heavy current and generate a very large starting torque (i.e. turning force). This is particularly useful in electric vehicles and trains where a powerful force is needed to initially set them in motion.<br />
<br />
[[File:Coreless_motor1.jpg|180px|thumb|right|A coreless motor - rotor and shell with permanent magnet visible inside the shell.]]<br />
In a '''coreless motor''' the rotor windings are formed into a resin bonded hollow cylinder - there is no iron core. This rotates around a static permanent magnet located within it. The magnetic field passes from one pole of the magnet through the rotor windings and then returns through the steel motor case, once again through the opposite side of the rotor and hence back to the other pole of the magnet.<br />
[[File:Coreless_motor2.jpg|180px|thumb|left|A coreless motor - Commutator and brushes.]]<br />
The current is fed to the rotor through brushes and a commutator just as in any other DC or universal motor. The absence of an iron core improves efficiency, saves weight and reduces inertia, allowing very rapid accelleration and decelleration.<br />
<br />
Coreless motors are often found in small quadrocopters and other toys as well in medical equipment, robotics and whenever a small highly efficient and responsive motor is required.<br />
<br />
Most hand power tools use universal motors. Computer fans, hard disk motors and larger quadrocopter and remote control models generally use electronically commutated motors.<br />
<br />
There is an excellent [http://woodgears.ca/motors/dc.html article] with an included video describing and demonstrating how a DC motor works.<br />
<br />
===Induction Motors===<br />
These are simpler in construction but not quite so easy to understand.<br />
<br />
If you move a magnet across a piece of metal, the moving magnetic field generates a circulating electric current in the metal. This current, in turn, creates a magnetic field which interacts with the applied field in such a way as to create a drag, opposing the motion.<br />
<br />
[[File:Img_1887a.jpg|180px|thumb|right|A small shaded pole induction motor, dismantled.]]<br />
The stator consists of two or more coils arranged to create a rotating magnetic field. The rotor contains a number of thick copper loops to maximise the drag created by the rotating magnetic field. The rotor speeds up until it's spinning nearly as fast as the rotating magnetic field.<br />
<br />
Induction motors only work on an [[Glossary:AC|AC]] supply (which reverses in direction 100 times per second), as this is how the stator can produce a rotating magnetic field.<br />
<br />
Since the frequency of the AC supply is fixed, you can't easily vary the speed of an induction motor. However, with 4 or 6 (or more) stator coils instead of 2, and by switching the way the AC supply is fed to them, it's possible to arrange for the rotating magnetic field to rotate at half, third (or some other fractional) speed.<br />
<br />
In most induction motors the stator produces more of an up and down than a true rotating magnetic field, but with a bit of a twist one way on the way up and the other on the way down. This means that the starting torque is low. Hence they are normally used where this doesn't matter, e.g. in a fan, which encounters little air resistance until it reaches full speed.<br />
<br />
[[File:Induction motor with starter winding.jpg|180px|thumb|left|An induction motor with starter winding.]]<br />
There are several ways in which the twist is obtained. In a shaded pole motor a thick loop of copper is wound around a portion of each pole (as can be seen in the first photo). This causes the magnetisation of that portion of the pole to be delayed slightly by the build up of current in the loop, so giving the required twist. The copper loop wastes power so this method is only used in small motors such as are very commonly found in desk fans.<br />
<br />
Larger motors have a second stator winding offset from the main one, which is fed with an out of phase current. A [[Basic_electronic_components#Capacitors|capacitor]] (a large cylindrical component which can't be missed) or sometimes a resistor provides the phase shift. The picture shows an example from a rotary lawn mower motor, with the 90 degree offset second winding clearly visible.<br />
<br />
(An interesting feature of the motor shown is that it had a braking mechanism to stop the blade rotating once the power was turned off. A metal disk is visible on the spindle with a spring underneath which pressed it against the three brake pads visible around the bearing. When power is applied, the magnetic field pulls this disk down and away from the brake pads. Corosion of the disk caused the braking action to become excessively fierce. The flats on the spindle then wore away the coresponding flats on a plastic impellor to which the blade was attached. The angular momentum of the blade then caused its retaining bolt to work loose.)<br />
<br />
The second stator winding may waste energy once the motor has started and hence may be switched out by a centrifugal switch. Alternatively there may be a thermistor which quickly heats up with the current flow and as it does so, its resistance increases so reducing the current in the second stator winding.<br />
<br />
Large industrial multi-horsepower induction motors are often fed from a 3-phase supply. With 3 windings (or a multiple of 3) fed from the 3 phases, these naturally create a rotating magnetic field and so are self-starting.<br />
<br />
There is an excellent [http://woodgears.ca/motors/ac.html article] with included video describing and explaining how induction motors work.<br />
<br />
===Synchronous Motors===<br />
<br />
These are similar to induction motors, in that the stator creates a rotating magnetic field. The difference is that the rotor is a permanent magnet and hence is forced to rotate at the same speed as the magnetic field instead of lagging in speed as in an induction motor.<br />
<br />
Imagine two tin cans, one inside the other. If you fill the space in between with treacle and rotate the outer can, it will drag the inner one around with it even if you resist its motion. The difference in speed will depend on the resistance you apply. That's like an induction motor. If instead of treacle, you attach the inner can to the outer one with springs, the inner will be forced to rotate at the same speed, but will stretch the springs and lag in position, though not in speed, as you increase the resistance. This is like a synchronous motor.<br />
<br />
Small synchronous motors are used in electro-mechanical timers and clocks where their rotation is locked to the [[Glossary:Frequency|frequency]] of the [[Glossary:AC|AC]] mains. Large industrial plant also sometimes uses very much bigger and more powerful synchronous motors. A car alternator and the generators in a power station are synchronous motors being used as generators.<br />
<br />
Since a synchronous motor doesn't work properly until the rotor gets up to speed, some cunning means must be applied to get it started. In small clock and timer motors this is usually achieved by the way the iron of the stator is shaped. As the magnetic field from the stator coil reverses with each cycly of the AC supply, the reversal of magnetism spreads progressively through the specially shaped iron in such a way as to give it a twist.<br />
<br />
A '''brushless motor''' is in fact just a synchronous motor driven by an electronic circuit to drive the stator coils and so create the rotating magnetic field.<br />
<br />
===Stepper Motors===<br />
<br />
Often, there is a requirement for a motor which, instead of turning continuously, can be commanded to turn by a predefined amount and stop. An example is the motor which drives the paper feed rollers in a printer. These must advance the paper by the width of the print head and stop after each row of pixels is printed. Similarly, an analogue quartz clock or watch usually steps its second hand on by a second every second. Stepper motors are used in both cases.<br />
<br />
There are different configurations but the simplest and easiest to understand consists of a stator comprising two coils at right angles, and a permanent magnet rotor within them. Initially, one coil is energised and the permanent magnet lines up with its magnetic field. If the other coil is also energised the magnet will turn 45 degrees to a position between the two, and complete the 90 degree turn when the first coil is turned off. Re-energising the first coil in the opposite direction will cause the rotor to continue another 45 degrees, and so on. In this way, a shaft attached to the permanent magnet can be turned 45 degrees at a time as needed. By reversing the sequence, it can be turned in the reverse direction if this is required.<br />
<br />
==Fault finding and Repair==<br />
All types of motor can jam if the bearings become clogged with dirt or dust, as can easily happen in power tools. Shavers, electric toothbrushes and kitchen appliances can seize up through ingress of water etc. Cleaning may be all that is required, but in the case of water, preventing the same happening again can be challenging. Investigate whether replacement seals are available. A seized bearing can often be freed with WD40, and a ball race clogged with dust can be cleaned with white spirit, but in either case, it's important to lubricate with suitable oil or grease once clean and dry, as neither WD40 nor white spirit are good lubricants.<br />
<br />
Small motors designed to run off batteries are often not designed to be taken apart though it may be possible to do so by bending the lugs that secure tham. Larger ones such as those intended for running off the mains can often be disassembled by removing two long bolts running through their length. In the case of DC and universal motors, on reassembly you will need to remove the brushes or hold them out of the way in order to slide the rotor into place with the commutator between them.<br />
<br />
If seized up, a motor draws a heavy current. It is designed to do so momentarily as it starts, but if prevented from turning it may overheat and damage the insulation, and in the worst case, burn out the windings. A burning smell is a strong indication of trouble, and damaged insulation may result in an inconsistent speed. If there's any evidence of deterioration of insulation the motor should be scrapped. (Specialist firms rewind large industrial motors but it's unlikely to be cost-effective for a domestic motor, nor a simple task to undertake yourself.)<br />
<br />
If there are no visible signs of deterioration it's worth testing the windings with a [[Glossary:Multimeter|multimeter]] on a [[Glossary:Resistance|resistance]] range. A low reading is normal as the applied [[Glossary:Volt|voltage]] is limited not by the resistance of the windings but by the dynamo effect which always opposes it.<br />
<br />
A common fault with DC and universal motors is wear of the carbon brushes which make contact with the commutator, or a dirty commutator. Excessive sparking is a sure sign that maintenance is urgently needed. The brushes are normally pressed against the commutator with a spring, but they may cease making good contact if they wear right down or if they are prevented from sliding down within their housings as they wear. Replacements can be obtained but you will need to take care selecting the right size. Replacements may be available for your specific make and model of appliance, otherwise, carefully measure the old brushes and their housing and you should be able to find suitable replacements online. If a brush wears right down to the spring the sparking is likely to permanently damage the commutator.<br />
<br />
Some professional and high-end DIY power tools have brushes which contain an embedded spring-loaded plastic pin. When the carbon wears down to its limit the pin is released, pushing the worn out brush away from the commutator to prevent further wear and permanent damage. Professionals have been known to discard expensive power tools which have suddenly stopped working for this reason - an easy fix if you can recognise the problem.<br />
<br />
Shaded pole induction motors are usually very reliable, but capacitor, thermistor and centrifugal mechanisms for starting may develop faults. If there is a capacitor it may show obvious signs of distress, otherwise test it if you can. If nothing else, you can use a multimeter on a resistance range to test that it isn't shorted.<br />
<br />
An electric motor contains lots of copper and iron - make sure you recycle it responsibly!<br />
<br />
[[Category:Theory]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3559Paper shredders2020-05-28T20:00:39Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
[[File:Shredder cutters.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder, showing the cutting wheels.]]<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
[[File:Shredder_motor_and_gears.jpg|180px|thumb|left|The motor and reduction gear chain in a domestic shredder.]]<br />
The cutters are driven by a fairly powerful motor (always an [[Glossary:Universal Motor|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
[[File:Shredder_paper_sensor.jpg|180px|thumb|right|The paper sensor in a domestic shredder, showing the infrared LED and the phototransistor on opposite sides of the paper slot.]]<br />
There are likely to be one or more safety interlocks. A mechanical or optical sensor generally detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens. A [[Glossary:Microswitch|microswitch]] may disable the motor if the shredding head is not positioned correctly on the bin. A small circuit board will probably interconnect these features, the motor, the main switch and probably a power indicator light. There may be a mains filter to prevent voltage spikes generated by the motor causing problems for other equipment on the same mains supply.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply fail with only moderate use.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of an unsuitable type is likely to clog the mechanism with oily paper and make matters worse.<br />
<br />
You will find a vacuum cleaner useful, or at least a dustpan and brush, to clear up the bits of shredded paper that will inevitably spread themselves around.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
[[File:Shredder_cover_off.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder with the cover off.]]<br />
Double-check that the device is unplugged before starting disassembly or going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible, which may have got all over the inside. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the [[Glossary:Fuse|fuse]] in the plug. This isn't often the problem but is very easy to check. There may be another fuse within the device. Also check that the lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating may or may not be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism are fortumately fairly unusual as they may not be easy to detect or diagnose unless indicated by obvious burning or a swollen [[Glossary:Electrolytic Capacitor|electrolytic capacitor]].<br />
<br />
If the problem is still not apparent you should start by checking for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3558Paper shredders2020-05-28T19:43:42Z<p>Pleriche: /* Mechanical problems */</p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
[[File:Shredder cutters.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder, showing the cutting wheels.]]<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
[[File:Shredder_motor_and_gears.jpg|180px|thumb|left|The motor and reduction gear chain in a domestic shredder.]]<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
[[File:Shredder_paper_sensor.jpg|180px|thumb|right|The paper sensor in a domestic shredder, showing the infrared led and the phototransistor on opposite sides of the paper slot.]]<br />
There are likely to be one or more safety interlocks. A mechanical or optical sensor generally detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens. A microswitch may disable the motor if the shredding head is not positioned correctly on the bin. A small circuit board will probably interconnect these features, the motor, the main switch and probably a power indicator light. There may be a mains filter to prevent voltage spikes generated by the motor causing problems for other equipment on the same mains supply.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply fail with only moderate use.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of an unsuitable type is likely to clog the mechanism with oily paper and make matters worse.<br />
<br />
You will find a vacuum cleaner useful, or at least a dustpan and brush, to clear up the bits of shredded paper that will inevitably spread themselves around.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
[[File:Shredder_cover_off.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder with the cover off.]]<br />
Double-check that the device is unplugged before starting disassembly or going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible, which may have got all over the inside. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked. There may be another fuse within the device. Also check that the lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating may or may not be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism are fortumately fairly unusual as they may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor.<br />
<br />
If the problem is still not apparent you should start by checking for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3557Paper shredders2020-05-28T19:42:58Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
[[File:Shredder cutters.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder, showing the cutting wheels.]]<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
[[File:Shredder_motor_and_gears.jpg|180px|thumb|left|The motor and reduction gear chain in a domestic shredder.]]<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
[[File:Shredder_paper_sensor.jpg|180px|thumb|right|The paper sensor in a domestic shredder, showing the infrared led and the phototransistor on opposite sides of the paper slot.]]<br />
There are likely to be one or more safety interlocks. A mechanical or optical sensor generally detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens. A microswitch may disable the motor if the shredding head is not positioned correctly on the bin. A small circuit board will probably interconnect these features, the motor, the main switch and probably a power indicator light. There may be a mains filter to prevent voltage spikes generated by the motor causing problems for other equipment on the same mains supply.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply fail with only moderate use.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of an unsuitable type is likely to clog the mechanism with oily paper and make matters worse.<br />
<br />
You will find a vacuum cleaner useful, or at least a dustpan and brush, to clear up the bits of shredded paper that will inevitably spread themselves around.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
[[File:Shredder_cover_off.jpg|180px|thumb|left|The underneath of a domestic cross-cut shredder with the cover off.]]<br />
Double-check that the device is unplugged before starting disassembly or going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible, which may have got all over the inside. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked. There may be another fuse within the device. Also check that the lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating may or may not be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism are fortumately fairly unusual as they may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor.<br />
<br />
If the problem is still not apparent you should start by checking for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3556Paper shredders2020-05-28T17:24:43Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
[[File:Shredder cutters.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder, showing the cutting wheels.]]<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
[[File:Shredder_motor_and_gears.jpg|180px|thumb|left|The motor and reduction gear chain in a domestic shredder.]]<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
[[File:Shredder_paper_sensor.jpg|180px|thumb|right|The paper sensor in a domestic shredder, showing the infrared led and the phototransistor on opposite sides of the paper slot.]]<br />
There are likely to be one or more safety interlocks. A mechanical or optical sensor generally detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens. A microswitch may disable the motor if the shredding head is not positioned correctly on the bin. A small circuit board will probably interconnect these features, the motor, the main switch and probably a power indicator light. There may be a mains filter to prevent voltage spikes generated by the motor causing problems for other equipment on the same mains supply.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply fail with only moderate use.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of un unsuitable type is likely to clog the mechanism with oily paper and make matters worse.<br />
<br />
You will find a vacuum cleaner useful, or at least a dustpan and brush, to clear up the bits of shredded paper.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked. There may be another fuse within the device. Also check that the lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating may or may not be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism are fortumately fairly unusual as they may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
[[File:Shredder_cover_off.jpg|180px|thumb|left|The underneath of a domestic cross-cut shredder with the cover off.]]<br />
Double-check that the device is unplugged before starting disassembly or going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible, which may have got all over the inside. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3555Paper shredders2020-05-28T17:10:00Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
[[File:Shredder cutters.jpg|180px|thumb|right|The underneath of a domestic cross-cut shredder, showing the cutting wheels.]]<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
[[File:Shredder_motor_and_gears.jpg|180px|thumb|left|The motor and reduction gear chain in a domestic shredder.]]<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
[[File:Shredder_paper_sensor.jpg|180px|thumb|right|The paper sensor in a domestic shredder, showing the infrared led and the phototransistor on opposite sides of the paper slot.]]<br />
There are likely to be one or more safety interlocks. A mechanical or optical sensor generally detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens. A microswitch may disable the motor if the shredding head is not positioned correctly on the bin. A small circuit board will probably interconnect these features, the motor, the main switch and probably a power indicator light. There may be a mains filter to prevent voltage spikes generated by the motor causing problems for other equipment on the same mains supply.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply wear out quickly.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of un unsuitable type is likely to make matters worse.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked. Also check that he lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
[[File:Shredder_cover_off.jpg|180px|thumb|left|The underneath of a domestic cross-cut shredder with the cover off.]]<br />
Double-check that the device is unplugged before starting disassembly or going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible, which may have got all over the inside. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=File:Shredder_motor_and_gears.jpg&diff=3554File:Shredder motor and gears.jpg2020-05-28T16:54:02Z<p>Pleriche: The motor and reduction gear chain in a domestic shredder.</p>
<hr />
<div>== Summary ==<br />
The motor and reduction gear chain in a domestic shredder.<br />
== Licensing ==<br />
{{cc-by-sa-4.0}}</div>Plerichehttps://wiki.restarters.net/index.php?title=File:Shredder_paper_sensor.jpg&diff=3553File:Shredder paper sensor.jpg2020-05-28T16:52:42Z<p>Pleriche: The paper sensor in a domestic shredder, showing the infrared led and the phototransistor on opposite sides of the paper slot.</p>
<hr />
<div>== Summary ==<br />
The paper sensor in a domestic shredder, showing the infrared led and the phototransistor on opposite sides of the paper slot.<br />
== Licensing ==<br />
{{cc-by-sa-4.0}}</div>Plerichehttps://wiki.restarters.net/index.php?title=File:Shredder_cover_off.jpg&diff=3552File:Shredder cover off.jpg2020-05-28T16:48:41Z<p>Pleriche: The underneath of a domestic cross-cut shredder with the cover off.</p>
<hr />
<div>== Summary ==<br />
The underneath of a domestic cross-cut shredder with the cover off.<br />
== Licensing ==<br />
{{cc-by-sa-4.0}}</div>Plerichehttps://wiki.restarters.net/index.php?title=File:Shredder_cutters.jpg&diff=3551File:Shredder cutters.jpg2020-05-28T16:46:32Z<p>Pleriche: The underneath of a domestic cross-cut shredder, showing the cutting wheels.</p>
<hr />
<div>== Summary ==<br />
The underneath of a domestic cross-cut shredder, showing the cutting wheels.<br />
== Licensing ==<br />
{{cc-by-sa-4.0}}</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3550Paper shredders2020-05-28T13:19:06Z<p>Pleriche: /* Principles of operation */</p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
There are likely to be one or more safety interlocks. A mechanical or optical sensor generally detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens. A microswitch may disable the motor if the shredding head is not positioned correctly on the bin. A small circuit board will probably interconnect these features, the motor, the main switch and probably a power indicator light. There may be a mains filter to prevent voltage spikes generated by the motor causing problems for other equipment on the same mains supply.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply wear out quickly.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of un unsuitable type is likely to make matters worse.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked. Also check that he lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
Double-check that the device is unplugged before going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Resources&diff=3549Resources2020-05-27T21:41:26Z<p>Pleriche: /* Disassembly and Repair */</p>
<hr />
<div>In this page, we list some of the websites that we in the Restart community have found most useful in helping us towards a repair.<br />
<br />
<br />
==General==<br />
* [http://artoftroubleshooting.com/book/ The Art of Trouble Shooting] book combines theory and practice, you’ll gain insight into the principles that underlie the diagnosis and repair of all machines.<br />
<br />
* [https://hackmd.io/5G4JLCw4Sm-jqac1f-Wo5A?both Awesome software running on old hardware] is an online, collaborative list of projects that attempt to compile or install “recent” software on old hardware, thus extending the life span of theses products.<br />
<br />
* [http://batteryuniversity.com/ Battery University] is a free educational website that offers both theoretical and practical battery information to engineers, educators, media, students and battery users alike, including advice on maximising rechargeable battery life and safe charging and use.<br />
<br />
* [http://www.electroboom.com/ Electroboom!] makes safety fun(ny) &#8211; definitely DO NOT try this at home.<br />
<br />
* [https://www.youtube.com/user/bigclivedotcom/videos BigCliveDotCom] has a YouTube channel in which he tears down and explains the working of numerous different electrical and electronic devices.<br />
<br />
* [https://www.youtube.com/user/EEVblog EEVblog] is another highly instructive YouTube channel, perhaps a little more technical, often discussing unusual devices.<br />
<br />
* [http://www.extremetech.com/computing/133294-raising-the-dead-can-a-regular-person-repair-a-damaged-hard-drive Raising the dead: Can a regular person repair a damaged hard drive?] is a very interesting article, debunking some of the myths on repairing hard drives. Also check the comments streams on this [http://hardware.slashdot.org/story/12/07/28/134201/can-a-regular-person-repair-a-damaged-hard-drive on Slashdot article]. (Note: hard drives are sealed against dust for a good reason - assume that one that has been opened may fail at any time.)<br />
<br />
* [http://www.oldversion.com/ Oldversion.com] is very useful when new softwares or their upgrades are too heavy or don’t work at all on an old pc (or implement new features you don’t like).<br />
<br />
==Disassembly and Repair==<br />
* The [https://espares.co.uk/advice espares Advice Centre] contains hundreds of simple diagnostic and repair guides and videos, as well a large collection of manuals, focused on domestic, kitchen and garden tools and appliances. There's a search box in which you can type "What's wrong with your appliance", or you can select the type of your appliance from a drop-down list and browse the avalable resources.<br />
* [http://www.badcaps.net/forum/index.php Bad Caps Forum] is a place to get help for suspected bad electrolytic capacitors.<br />
<br />
* [http://www.flickr.com/groups/camrepair/pool/with/8187258807/#photo_8187258807 Camera Repair Flickr Pool] is a pool on Flickr with photos of camera designs, including digital cameras.<br />
<br />
* [http://www.jestineyong.com/ Electronics Repair] presents tips and guides by Jestine Yong (and his friends around the world) to repair load of electronics products. Super useful.<br />
<br />
* [http://www.fixitclub.com/ Fixit Club] consists of simple instructions and tips on troubleshooting and repairing household things that break by best-selling &#8220;How Does it Work?&#8221; author Dan Ramsey.<br />
<br />
* [http://www.fixya.com/ FixYa] is building a crowdsourced database of help queries and personalised answers.<br />
<br />
* [http://www.ifixit.com iFixit] makes it easy to fix things with online step-by-step [http://www.ifixit.com/Guide repair guides], [http://www.ifixit.com/Troubleshoot troubleshooting tips], and a thriving community of [http://www.ifixit.com/Answers repair technicians] who want to help.<br />
<br />
* [http://lowendmac.com/ Lowend Mac] proposes we use &#8220;Apple gear as long as it helps you remain productive and meets your needs, upgrading only as necessary&#8221; and helps maintain and use older kit for longer.<br />
<br />
* [http://www.powerbookmedic.com/mac-repair.php Powerbook Medic] is an online library of repair videos mostly of Apple products.<br />
<br />
* [http://www.reddit.com/r/computertechs Reddit&#8217;s Computer Technicians] is for people who are repair professionals or aspire to be. &#8220;End users&#8221; are encouraged to use [http://www.reddit.com/r/techsupport /r/techsupport]<br />
<br />
* [http://www.youtube.com/user/RepairsUniverse?feature=watch Repairs Universe video library] has a growing number of videos of smartphone and tablet repairs and teardowns.<br />
<br />
* [http://www.repairfaq.org/ sci.electronics.repair FAQ] is a comprehensive historical archive of tips and guides on repairing many kinds of consumer electronics.<br />
<br />
==Manuals and Reference Info==<br />
* [http://www.manualslib.com/ manualslib.com] contains a large repository of manuals for various types of device.<br />
<br />
* [http://www.tim.id.au/blog/tims-laptop-service-manuals/ Future proof: Tim’s laptop service manuals] is a collection of professional, official documents published by the various laptop makers, either for their own technicians or for the use of the general public.<br />
<br />
* [https://www.alldatasheet.com/ alldatasheet.com] has a wide selection of semiconductor datasheets though the results it gives often need to be read very selectively. Often a device has a marking that is only part of the full part number due to space limitations. You can use the pull down next to the search box and select "marking" then enter the marking you see on the semiconductor, then search. Hopefully, this will find the part you are looking for.<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3548Paper shredders2020-05-27T21:20:33Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
A mechanical or optical sensor detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply wear out quickly.<br />
<br />
Heavy duty and commercial shredders require regular oiling. This might be beneficial for domestic shredders but if you do, only use special shredder oil. Never use WD40 as this is not a lubricant. Vegetable oils (icluding olive oil) may go rancid, and any oil of un unsuitable type is likely to make matters worse.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked. Also check that he lead is in good condition, the plug is correctly fitted and there are no loose connections.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
Double-check that the device is unplugged before going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3547Paper shredders2020-05-27T21:01:04Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally. Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
A mechanical or optical sesnsor detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply wear out quickly.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect or diagnose unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
Double-check that the device is unplugged before going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but unfortunately this is not usually fixable.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3546Paper shredders2020-05-27T20:55:44Z<p>Pleriche: </p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally.Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device. It could be very dangerous to operate whilst partially disassembled.<br />
<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in opposite directions. The paper is drawn in between them so cutting it into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections are reversed either to the field winding or to the brushes of the electric motor, causing it to run backwards.<br />
<br />
A mechanical or optical sesnsor detects when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens.<br />
<br />
Problems are most commonly caused by demanding too much of the shredder, whether too many sheets at once, unsuitable materials, or heavy use for too long at a time. A poor quality shredder may simply wear out quickly.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. If you continue to feed paper in when the bin is already full, it is likely to get wrapped around the cutters and eventually jam. Some shredders are designed to take CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
Double-check that the device is unplugged before going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but there is little that can be done about it.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3545Paper shredders2020-05-27T20:16:57Z<p>Pleriche: /* Mechanical problems */</p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally.Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device.<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in oposit directions. The paper is drawn in between them so cutting into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections to the field winding of the electric motor (or to the brushes) are reversed, causing it to run backwards.<br />
<br />
A mechanical or optical sesnsor detect when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
Jams are very common, and may be due to feeding too much paper in at once or a foreign object such as a paper clip. Some shredders are designed to tak CDs and DVDs, but feeding one into a shredder which is not designed to take it may well cause a jam or the motor to overheat.<br />
<br />
Double-check that the device is unplugged before going anywhere near the cutters. The first thing to do is often to remove as much shredded paper from the cutters as possible. Often, it gets wrapped around them. If there's any other cause of a jam you should now be able to see it.<br />
<br />
Not uncommonly, a jam or heavy use can cause one of the gear wheels to be stripped. This should be obvious, but there is little that can be done about it.<br />
<br />
==External links==<br />
* External links (if any) as bullet points.<br />
* If non, delete this section.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3544Paper shredders2020-05-27T20:07:27Z<p>Pleriche: /* Electrical problems */</p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally.Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device.<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in oposit directions. The paper is drawn in between them so cutting into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections to the field winding of the electric motor (or to the brushes) are reversed, causing it to run backwards.<br />
<br />
A mechanical or optical sesnsor detect when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens.<br />
<br />
==Electrical problems==<br />
Unless the problem is visually obvious, you will need a [[How_to_use_a_multimeter|multimeter]] and probably a basic understanding of [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motors]].<br />
<br />
If there is no life in the shredder the first thing to check is the fuse in the plug. This isn't often the problem but is very easily checked.<br />
<br />
It's possible the motor may have burnt out, in which case signs of overheating should be obvious. Even if it looks good, use a multimeter to check the resistance of the motor field windings and the resistance of the rotor measured between the brushes. Check that the commutator is clean and not pitted from sparking, and that the brushes are in good order.<br />
<br />
There may be a [[Protection_components#Thermal_fuses|thermal cutout]] attached to or inside the motor which could have tripped. If it's open circuit and provided it's accessible it should be replaceable, though it may not be easy to work out what temperature rating the replacement should have.<br />
<br />
Problems with the paper detect mechanism may not be easy to detect unless indicated by obvious burning or a swollen electrolytic capacitor, but fortumately they are fairly unusual.<br />
<br />
If the problem is still not apparent you will have to check for continuity from the plug, through the switch and the motor, and back to the plug.<br />
<br />
==Mechanical problems==<br />
<br />
<br />
==External links==<br />
* External links (if any) as bullet points.<br />
* If non, delete this section.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3543Paper shredders2020-05-27T19:40:19Z<p>Pleriche: /* Principles of operation */</p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally.Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device.<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patience, could be reassembled. Cross-cut shredders are considerably more secure as these chop each strip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in oposit directions. The paper is drawn in between them so cutting into strips. In a cross-cut shredder, the circular cutters also have spikes which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor (always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]]) through a gear chain to reduce the speed and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper back out again. In this position, the connections to the field winding of the electric motor (or to the brushes) are reversed, causing it to run backwards.<br />
<br />
A mechanical or optical sesnsor detect when a piece of paper is inserted into the feed slot, only allowing the motor to run when this happens.<br />
<br />
==Electrical problems==<br />
<br />
<br />
==Mechanical problems==<br />
<br />
<br />
==External links==<br />
* External links (if any) as bullet points.<br />
* If non, delete this section.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Paper_shredders&diff=3542Paper shredders2020-05-27T16:49:45Z<p>Pleriche: /* Principles of operation */</p>
<hr />
<div>This page covers the mechanical and electrical problems that can arise with domestic paper shredders.<br />
<br />
==Summary==<br />
Paper shredders are simple electromechanical devices but a fairly powerful motor is required to operate the shredding mechanism, and that power can break things internally.Problems can be divided into mechanical and electrical, but your first task might be to determine which it is in your particular case.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Always unplug before opening the device.<br />
::Keep fingers, hair and loose clothing well away from the mechanism.<br />
<br />
==Principles of operation==<br />
There are two types of shredder: strip-cut and cross-cut. Strip-cut shredders simply cut the paper into narrow strips which, with patence, could be reassembled. Cross-cut shredders are considerably more secure as these chop each trip into many short sections.<br />
<br />
The shredding action is accomplished by two interlocking sets of circular cutterrs which rotate in oposit directions. The paper is drawn in between them so cutting into strips, and in a cross-cut shredder, the circular cutters also have spike which break up each strip.<br />
<br />
The cutters are driven by a fairly powerful motor, always an [[Electric_motors#DC_and_Universal_(AC/DC)_Motors|AC/DC motor]] through a gear chain to reduce the spead and increase the torque. A switch controls power to the motor. This is normally a 3 position switch with off, forward and reverse positions. The reverse position can be used in the case of a jam, to feed the paper out again. In this position, the connections to the field winding of the electric motor (or to the brushes) are reversed, causing it to run backwards.<br />
<br />
==Electrical problems==<br />
<br />
<br />
==Mechanical problems==<br />
<br />
<br />
==External links==<br />
* External links (if any) as bullet points.<br />
* If non, delete this section.<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Grooming_products&diff=3541Grooming products2020-05-27T12:20:13Z<p>Pleriche: </p>
<hr />
<div>This is currently a skeleton page. Please help by adding your contributions either here or in the associated Discussion page.<br />
<br />
This page will cover hair dryers, curlers nd straighteners, beard trimmers, electric razors and all such gadgets.<br />
<br />
==Summary==<br />
<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::As with all mains electrical devices, dangerous voltages may be exposed when opened.<br />
<br />
==Hair driers==<br />
<br />
<br />
==Hair straighteners and curlers==<br />
<br />
<br />
==Hair and beard trimmers==<br />
<br />
<br />
<br />
[[Category:Fixing]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Talk:Grooming_products&diff=3540Talk:Grooming products2020-05-27T12:13:14Z<p>Pleriche: </p>
<hr />
<div>'''This is the Grooming products Discussion page.'''<br />
<br />
You are encouraged to leave any comments or queries below. Please sign all contributions by appending 2 hyphens and 4 tildes (<nowiki>--~~~~</nowiki>), which will be automatically expanded into your user name and a time stamp.<br />
----<br />
==Hair driers==<br />
Useful notes from https://talk.restarters.net/uploads/short-url/u3TITNv8AILwdq4I774Zw11RYvB.pdf<br />
If the air flow is impeded or the motor jams the element will overheat very quickly. There should be a thermal cut-out which will operate if the air flow is temporarily impeded for example by a towel. This may be self-resetting. There may also be a non-resettable cut-out designed to prevent a fire if the overheating starts to approach a dangerous level. If this has operated there may already be some damage, and you should make sure you've identified and corrected the root cause of the problem. If you come across a vintage hair drier without these cut-outs you should consider carefully whether it's safe to use. --[[User:Pleriche|Pleriche]] ([[User talk:Pleriche|talk]]) 12:11, 27 May 2020 (UTC)</div>Plerichehttps://wiki.restarters.net/index.php?title=Talk:Grooming_products&diff=3539Talk:Grooming products2020-05-27T12:11:43Z<p>Pleriche: </p>
<hr />
<div>'''This is the Grooming products Discussion page.'''<br />
<br />
You are encouraged to leave any comments or queries below. Please sign all contributions by appending 2 hyphens and 4 tildes (<nowiki>--~~~~</nowiki>), which will be automatically expanded into your user name and a time stamp.<br />
----<br />
==Hair driers==<br />
Useful notes from https://talk.restarters.net/uploads/short-url/u3TITNv8AILwdq4I774Zw11RYvB.pdf<br />
If the air flow is impeded or the motor jams the element will overheat very quickly. There should be a thermal cut-out which will operate if the air flow is temporarily impeded for example by a towel. This may be self-resetting. There may also be a non-resettable cut-out designed to prevent a fire if the overheating starts to approach a dangerous level. If this has operated there may already be some damage, and you should make sure you've identified and corrected the root cause of the problem. --[[User:Pleriche|Pleriche]] ([[User talk:Pleriche|talk]]) 12:11, 27 May 2020 (UTC)</div>Plerichehttps://wiki.restarters.net/index.php?title=Steam_Irons&diff=3538Steam Irons2020-05-27T11:58:08Z<p>Pleriche: /* Thermostat */</p>
<hr />
<div>The first challenge with a modern steam irons may be to disassemble it. Unfortunately the repair options can be limited, nevertheess some of what can be attempted is described here.<br />
<br />
==Summary==<br />
Steam irons are regularly seen at Restart parties. They can be challenging to open, and as with any appliance which mixes water and electricity the fault can often be due to a failure, ultimately, to keep them sufficiently apart.<br />
<br />
==Disassembly==<br />
[[File:Img_0373a.jpg|200px|thumb|right|Steam iron disassembly.]]<br />
Usually there will be one or two easily accessible screws at the back of the handle of the iron. These typically release a cover providing access to the cable connections. If the problem is a worn cable, hopefully this may be all the disassembly required.<br />
<br />
Another screw or screws near the front may be hidden for example under the steam button, but even after removing these the handle cover can be tricky to remove. Often there will be a series of clips down the sides, but this may not be all. In the iron illustrated there was another clip to be released on the top just forward of the cable which required the whole of the top cover to be pushed forward.<br />
<br />
With the top cover off it should be possible to find the screws which release the whole of the plastic top, in order to access the thermostat etc. and (if not already accessible) to replace the mains lead.<br />
<br />
On reassembly, ensure that any tubes associated with the water reservoir and steam delivery are properly connected.<br />
<br />
== Specific Faults ==<br />
You should be able to diagnose electrical faults with a [[How_to_use_a_multimeter|multimeter]]. Trace electrical connectivity from the mains plug live pin through the flex, the thermostat, the element and back through the flex to the mains plug neutral pin. A 240V 750W iron will have an element with a resistance of around 75Ω.<br />
<br />
=== Worn Flex ===<br />
Because irons are moved around a lot, this causes strain on the mains lead. One or more of the conductors can break, usually close to the iron body. Locating the break may be tricky, although usually it will be close to the body and can often be felt by bending the flex conductors individually.<br />
<br />
You can cut the existing flex back to before the break then reconnect it, but for safety and lengevity you will probably do better by replacing it with a compatible heat-resistant flex. Seartch online for cotton covered iron flex, or try a local domestic appliance repair shop if you have one.<br />
<br />
=== Thermostat ===<br />
[[File:Steam iron thermostat.jpg|200px|thumb|right|Steam iron thermostat.]]<br />
The thermostat switches the element off when the iron gets up to temperature and back on as it cools down a bit.<br />
Usually it consists of a pair of contacts, one of which is a bimetallic strip which bends away from the other when it heats up.<br />
The distance between the contacts is adjusted by a threaded shaft attached to the temperature control knob.<br />
<br />
If the electrical continuity is otherwise good and the element shows the correct resistance, but the iron won't heat up, try cleaning the thermostat contacts and checking that they do actually make electrical contact when they come together.<br />
<br />
In addition to the thermostat, there may be a [[Protection_components#Thermal_fuses|thermal cutout switch]] to prevent excessive overheating should the thermostat get stuck on. This may or may not be resettable. You can test it for continuity with a multimeter.<br />
<br />
=== No Steam ===<br />
If the iron is heating up but isn't producing steam, this is almost certainly a mechanical problem, usually caused by limescale: descale it.<br />
<br />
Another possibility is that there is a hole which allows air into the water chamber which has got blocked:<br />
the symptom in this case will usually be an initial small puff of steam followed by nothing. A good place to start looking for the hole is in the filler cap.<br />
<br />
===Control electronics===<br />
[[File:Steam iron control circuit.jpg|200px|thumb|right|Failed control circuit from a steam iron.]]<br />
Some steam irons include control electronics which may, for example, turn the iron off or on lower power if standing stationary for a while, or turn it off much more quickly for safety if it's left flat. In the example shown, the resin-potted control module has cracked, most likely due expansion of a failing electrolytic capacitor. Unless a spare module can be obtained this is probably unrepairable. (Simply bridging this module would probably be dangerous.)<br />
<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=File:Steam_iron_thermostat.jpg&diff=3537File:Steam iron thermostat.jpg2020-05-27T11:56:26Z<p>Pleriche: A steam iron thermostat showing the heat control knob spindle (red), the contacts (green arrow) and the bimetallic strip (yellow arrow).</p>
<hr />
<div>== Summary ==<br />
A steam iron thermostat showing the heat control knob spindle (red), the contacts (green arrow) and the bimetallic strip (yellow arrow).<br />
== Licensing ==<br />
{{cc-by-sa-4.0}}</div>Plerichehttps://wiki.restarters.net/index.php?title=Steam_Irons&diff=3536Steam Irons2020-05-27T11:50:13Z<p>Pleriche: /* No Steam */</p>
<hr />
<div>The first challenge with a modern steam irons may be to disassemble it. Unfortunately the repair options can be limited, nevertheess some of what can be attempted is described here.<br />
<br />
==Summary==<br />
Steam irons are regularly seen at Restart parties. They can be challenging to open, and as with any appliance which mixes water and electricity the fault can often be due to a failure, ultimately, to keep them sufficiently apart.<br />
<br />
==Disassembly==<br />
[[File:Img_0373a.jpg|200px|thumb|right|Steam iron disassembly.]]<br />
Usually there will be one or two easily accessible screws at the back of the handle of the iron. These typically release a cover providing access to the cable connections. If the problem is a worn cable, hopefully this may be all the disassembly required.<br />
<br />
Another screw or screws near the front may be hidden for example under the steam button, but even after removing these the handle cover can be tricky to remove. Often there will be a series of clips down the sides, but this may not be all. In the iron illustrated there was another clip to be released on the top just forward of the cable which required the whole of the top cover to be pushed forward.<br />
<br />
With the top cover off it should be possible to find the screws which release the whole of the plastic top, in order to access the thermostat etc. and (if not already accessible) to replace the mains lead.<br />
<br />
On reassembly, ensure that any tubes associated with the water reservoir and steam delivery are properly connected.<br />
<br />
== Specific Faults ==<br />
You should be able to diagnose electrical faults with a [[How_to_use_a_multimeter|multimeter]]. Trace electrical connectivity from the mains plug live pin through the flex, the thermostat, the element and back through the flex to the mains plug neutral pin. A 240V 750W iron will have an element with a resistance of around 75Ω.<br />
<br />
=== Worn Flex ===<br />
Because irons are moved around a lot, this causes strain on the mains lead. One or more of the conductors can break, usually close to the iron body. Locating the break may be tricky, although usually it will be close to the body and can often be felt by bending the flex conductors individually.<br />
<br />
You can cut the existing flex back to before the break then reconnect it, but for safety and lengevity you will probably do better by replacing it with a compatible heat-resistant flex. Seartch online for cotton covered iron flex, or try a local domestic appliance repair shop if you have one.<br />
<br />
=== Thermostat ===<br />
The thermostat switches the element off when the iron gets up to temperature and back on as it cools down a bit.<br />
Usually it consists of a pair of contacts, one of which is a bimetallic strip which bends away from the other when it heats up.<br />
The distance between the contacts is adjusted by a threaded shaft attached to the temperature control knob.<br />
<br />
If the electrical continuity is otherwise good and the element shows the correct resistance, but the iron won't heat up, try cleaning the thermostat contacts and checking that they do actually make electrical contact when they come together.<br />
<br />
In addition to the thermostat, there may be a [[Protection_components#Thermal_fuses|thermal cutout switch]] to prevent excessive overheating should the thermostat get stuck on. This may or may not be resettable. You can test it for continuity with a multimeter.<br />
<br />
=== No Steam ===<br />
If the iron is heating up but isn't producing steam, this is almost certainly a mechanical problem, usually caused by limescale: descale it.<br />
<br />
Another possibility is that there is a hole which allows air into the water chamber which has got blocked:<br />
the symptom in this case will usually be an initial small puff of steam followed by nothing. A good place to start looking for the hole is in the filler cap.<br />
<br />
===Control electronics===<br />
[[File:Steam iron control circuit.jpg|200px|thumb|right|Failed control circuit from a steam iron.]]<br />
Some steam irons include control electronics which may, for example, turn the iron off or on lower power if standing stationary for a while, or turn it off much more quickly for safety if it's left flat. In the example shown, the resin-potted control module has cracked, most likely due expansion of a failing electrolytic capacitor. Unless a spare module can be obtained this is probably unrepairable. (Simply bridging this module would probably be dangerous.)<br />
<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=File:Steam_iron_control_circuit.jpg&diff=3535File:Steam iron control circuit.jpg2020-05-27T11:39:16Z<p>Pleriche: A resin-encased control circuit from a steam iron. The resin is cracked, probably due to a failedelectrolytic capacitor.</p>
<hr />
<div>== Summary ==<br />
A resin-encased control circuit from a steam iron. The resin is cracked, probably due to a failedelectrolytic capacitor.<br />
== Licensing ==<br />
{{cc-by-sa-4.0}}</div>Plerichehttps://wiki.restarters.net/index.php?title=Yes,_you_can_fix_your_laptop!&diff=3534Yes, you can fix your laptop!2020-05-27T11:24:25Z<p>Pleriche: /* CD/DVD drive */</p>
<hr />
<div>Fixing a laptop isn't nearly as scary as you might think. Here's what you can hope to do and how to set about doing it.<br />
<br />
==Summary==<br />
Most traditional "clamshell" laptops are relatively straightforward to disassemble and repair. Although they don't contain as many standard parts as a desktop computer, most parts can be replaced and some can be upgraded.<br />
<br />
If you decide a laptop is beyond repair there may still be the possibility of reusing a few of the components.<br />
<br />
Unfortunately, newer ultra-thin laptops offer less scope, and a few are virtually unrepairable.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Backup important data before you start. Things don't often go badly wrong, but why take the risk?<br />
<br />
::Before starting work, disconnect the power and remove a user-replaceable battery if there is one.<br />
<br />
::Consider whether you need to take [[Electrostatic Discharge Precautions|antistatic]] precautions. Brushes and vacuum cleaners can create static.<br />
<br />
==Before you start==<br />
For any but the most basic tasks, the first thing to do is to search for an online repair or disassembly guide or video. One of the best places to look is iFixit.com but a search engine will give others. Many laptops come in several variants so if you can't find your precise model then look through the guides for the closest match and it should give you a very good idea how to proceed.<br />
<br />
The only tools you will normally need are a set of small screwdrivers and a prying tool - a thin-bladed tool for prying open the clips which very often hold the case together. The iFixit [https://eustore.ifixit.com/en/Tools/Prying-Opening/Jimmy.htm Jimmy] is ideal. A knife, preferably with a thin blade and a round end and not too sharp will do if you have nothing else.<br />
<br />
For the intermediate level tasks you will also need a means of organising the screws. Pill boxes are an excellent choice but egg boxes will do. Be sure to record for each pill box or egg box compartment which disassembly step the screws came from. You think you'll remember, but believe me, you won't!<br />
<br />
Another good solution is to stick the screws to a sheet of paper with Blu-tac. So long as you only use half the sheet you can fold it over in order to keep the screws reasonably safe if you need to put it aside and come back later to complete the job. Write the disassembly step or where the screws came from next to each blob of Blu-tac. On reassembly, if Blu-tac sticks to the screw threads you can remove it by dabbing them on a piece of clean Blu-tac; Blu-tac sticks to Blu-tac better than it sticks to screws.<br />
<br />
Sometimes you will find arrows against some of the screws on the base of a laptop or on a motherboard. These are the screws to undo; leave any others, at least for the time being.<br />
<br />
If the laptop case won't come apart, remember, there's always one more screw! If for instance you can ease it apart by a centimetre or two on the left side but only by a few millimetres on the right, the remaining screw is almost certainly close to the right hand side.<br />
<br />
On reassembly you may sometimes find at a certain step you have more holes than screws to go in them. This will be because the other holes are for screws to hold the case on. If you put screws in those holes now you'll have a problem later. A good disassembly guide will make this clear.<br />
<br />
==What can you do?==<br />
In the case of traditional clamshell laptops, many are similar in construction, though some you open from the top and others from the bottom. More modern ultra-thin and convertible laptops tend to be simpler in construction but not necessarily easier to take apart. In particular:<br />
* Some are glued together and almost impossible to repair whereas with others simply removing the back gives access to the motherboard and main components.<br />
* Batteries tend not to be user-replaceable but built-in. They are custom assemblies shaped to fit within the laptop case rather than made out of standard cylindrical lithium cells.<br />
* The keyboard may be built into the case top and the [[Glossary:RAM|RAM]] soldered directly to the motherboard making them much harder to replace.<br />
<br />
The various tasks you can undertake are listed below, grouped roughly according to difficulty for a typical clamshell laptop. That said, what's easy on one laptop can require extensive disassembly on another, or vice versa.<br />
<br />
===Easy===<br />
<br />
====Battery removal or replacement====<br />
[[File:Battery_removal.jpg|180px|thumb|right|Removing a laptop battery.]]<br />
<br />
Many laptops allow you to remove the battery simply by releasing a couple of catches. Often, one is spring loaded. With newer ultra-thin and convertible laptops you will probably need to remove the case back. Look for an online guide to show you how.<br />
<br />
Unfortunately, sourcing replacement batteries is something of a minefield. Genuine manufacturer's batteries tend to be outrageously expensive, and if they have been sitting on a shelf for several years they may already be losing capacity. After market batteries may or may not be worth the money and may even be pulled from scrap laptops. Some are re-manufactured using fresh cells, which is fine so long as the smart controller within them has been reset. Other things being equal, a mid-price battery could be a good choice. To protect yourself:<br />
* Check the vendor's warranty period and returns policy.<br />
* Check the vendor's reputation and other purchasers' experience on independent review sites such as Trustpilot. Be aware that favourable reviews can be bought.<br />
* When the battery arrives, check whether you are required to register a warranty for it to be valid, though under consumer law this should not be necessary.<br />
<br />
Batteries for ultra-thin and convertible laptops are harder to replace and may be harder to source.<br />
<br />
====RAM replacement or upgrade====<br />
[[File:RAM removal.jpg|180px|thumb|left|Removing the RAM from a laptop.]]<br />
Upgrading your [[Glossary:RAM|RAM]] (main working memory) is probably the easiest upgrade you can do, and at the same time, often one of the most effective. You can usually access the RAM slots simply by removing a service cover on the base. Two clips, one either side, hold each memory module in its slot. On replacement, ensure the memory module is seated as far as it will go in the connector before angling it down to engage the clips.<br />
<br />
If your laptop has a 32 bit processor or runs a 32 bit version of Windows and has less than 4GB of RAM, then upgrading to 4GB (the maximum it can use) is generally well worth while and relatively inexpensive.<br />
<br />
(If you're not sure whether your laptop is 32 or 64 bit, press the Windows key and "R" and type msinfo32. Press Return. A complete run-down of your computer's resources will be given.)<br />
<br />
Upgrading a 64 bit laptop beyond 4GB may well be worthwhile, particularly if you do graphics, video or audio editing, or commonly have many browser tabs open.<br />
<br />
<br />
====Replacement of a damaged or faulty keyboard====<br />
[[File:Keyboard_removal.jpg|180px|thumb|right|Removing a laptop keyboard.]]<br />
Many people put up with a damaged or unreliable keyboard without realising just how cheap and easy it might be to replace.<br />
<br />
Search for an online guide. Quite commonly, all you have to do is release a series of catches along one long edge of the keyboard in order to lift it out. A ribbon cable will still be connecting it to the motherboard, and you can release this by carefully lifting or releasing a clamping bar. (See [[Connectors#Ribbon_connectors|Ribbon Connectors]].)<br />
<br />
On some laptops the keyboard is additionally held in place by one or more screws which you have to unscrew from the bottom of the case, or hidden under a snap-on bezel between the keyboard and screen. On others, the keyboard is integral with the case top, but still not that hard to remove.<br />
<br />
Replacement keyboards for most models of laptop are available online for around £20. Make sure you get one for your exact model. Also, make sure you get one with the right national keyboard layout, otherwise you may find some keys in unfamiliar places.<br />
<br />
<br />
====Hard disk replacement or upgrade====<br />
[[File:Hard_disk_removal.jpg|180px|thumb|left|Removing a laptop hard disk.]]<br />
Very often you can access the [[Glossary:Hard Disk|hard disk]] simply by removing a service cover on the base. On some laptops, particularly consumer grade ones, a first level of disassembly may be required.<br />
<br />
[[SSD Migration and Troubleshooting|Replacing a hard disk with a solid state disk]] is probably the most effective way of injecting new life into an old laptop. But if it's running slowly because of unwanted software, pop-ups or viruses then you should tackle those first.<br />
<br />
If you are running out of storage space then fitting a larger hard disk is easy. Laptop hard disks are highly standardised in size though they do come in several different heights. If you are fitting one with a higher capacity, check that it's no thicker than the old one.<br />
<br />
If you're happy to reinstall your [[Glossary:Operating System|operating system]] on your new disk then that's the easiest way to go. To copy your existing system you will need appropriate disk cloning software. Copying a hard disk to a smaller SSD requires an extra step to shrink the file system.<br />
<br />
<br />
====CD/DVD drive replacement====<br />
[[File:Optical_disk_removal.jpg|180px|thumb|right|Removing a laptop CD/DVD drive.]]<br />
A faulty CD/DVD drive is easily replaced, or you might wish to replace it with a better one, or a Blu-ray drive. They are all a standard size, but come in a couple of different heights.<br />
<br />
The CD/DVD drive normally just slides into the laptop shell, but it's retained by a screw at the back, somewhere around the middle of the laptop. Quite often you will be able to remove this screw with no more disassembly than removing the service cover on the bottom.<br />
<br />
The drive will usually have a bezel which is shaped and styled to match the laptop, and this can be unclipped and transferred to a new drive.<br />
<br />
<br />
===Just a little harder===<br />
<br />
====Replacing the WiFi adapter====<br />
[[File:WiFi_adapter_removal.jpg|180px|thumb|left|Removing a laptop WiFi adapter.]]<br />
WiFi is supposed to be standardised, but nevertheless a particular brand of adapter will sometimes refuse to work reliably with a particular router. The WiFi adapter is often a small easily replaceable board.<br />
<br />
It may be very easily accessible along with the RAM and the hard disk under a service cover on the bottom of the case. Gently lift off the two antenna connectors and remove one or two screws holding it in place, then remove the adapter from the socket it fits in, which similar to a RAM socket but smaller.<br />
<br />
On some laptops the WiFi adapter may not be quite so easily accessed, requiring a first level of disassembly.<br />
<br />
<br />
====Cleaning the fan====<br />
After a few years it's very common for the fan (or more usually the cooling fins) to get clogged with matted dust. This will cause the laptop to overheat, the fan to run continuously and perhaps noisily, and may cause the laptop to crash.<br />
<br />
[[Clean_up!_Cool down!|Cleaning the fan]] is not difficult but usually requires fairly extensive disassembly of the laptop, which may be daunting. Don't be put off. Given a good disassembly guide, this is perfectly doable.<br />
<br />
<br />
====Replacing the power connector====<br />
A damaged power connector which no longer connects reliably is not uncommon. In many cases it's replaceable. As with cleaning the fan, this is likely to require fairly extensive disassembly but often, the power connector itself is easily removed from the case and simply plugs into the motherboard via a flying lead.<br />
<br />
If you're unlucky you may find the power connector is soldered directly to the motherboard, in which case you will need to be confident with a soldering iron to replace it. Or you might find the problem is that the laptop case is broken around the power connector so that you can't push the plug fully home.<br />
<br />
<br />
====Replacing the backup battery====<br />
[[File:Laptop_backup_battery.jpg|180px|thumb|right|A laptop backup battery.]]<br />
All laptops contain a small backup battery, often (for historical reasons) erroneously called the CMOS battery. This keeps the clock running when neither mains power nor a main battery are present. (Removing this battery will not reset the BIOS settings and BIOS password as sometimes thought. These have been held in [[Glossary:Flash|flash]] memory similar to a memory stick in all computers since about the 1990's.)<br />
<br />
This battery is usually a non-rechargeable lithium coin cell, or sometimes a rechargeable nickel battery in a plastic sleeve. Either way it may fail after maybe 10 years or more causing the computer to lose its time and date on loss of power. If you're lucky, it will be on a flying lead connected to the motherboard via a miniature plug and socket, or it might be a coin cell in a socket. Otherwise it could be soldered in and a certain level of disassembly may be required to access it. If you can't get hold of an identical replacement, provided it's the same voltage and the same chemistry it should be fine. If you need to improvise at all, make sure you get a "tagged" battery having tags spot-welded to it which you can solder to. It's not possible to solder directly to a battery of any type without damaging it.<br />
<br />
===More difficult===<br />
<br />
====Fixing a broken hinge====<br />
A broken laptop hinge is a very common problem. Unfortunately it's nearly always the plastic the hinge is attached to that is broken rather than the hinge itself. The hinge screws usually screw into brass bushes set in plastic pillars which are part of the case moulding. These pillars are simply not strong enough in many laptops and break off.<br />
<br />
Repair can be quite difficult. If you glue the plastic pillar back to the case it has to be positioned very precisely if it's not to be strained when you screw the hinge back to it. If possible, it's best to glue the pillar back to the case, still attached to the hinge, in order to position it accurately. Rapid setting two part [[Sticky_Stuff#Epoxy|epoxy glue]] is best, and once it's lightly secured, build up more epoxy around the break to reinforce it.<br />
<br />
An alternative approach is given in this [https://www.ifixit.com/Guide/Disassembling+Laptop+Toshiba+Satellite+P855+P850+plus+Hinge+FIX/36744 iFixit guide] using wall plugs and multi-purpose or wood screws.<br />
<br />
====Cracked casing====<br />
If the laptop has been dropped the case may be cracked or broken. A cover or bezel or the clips that retain it may be broken, causing it to keep falling off. This may be challenging to repair properly. The simple, if somewhat inelegant solution is to secure it with sticky tape. Black PVC tape will probably match the case. Gaffer or Duct tape will be stronger.<br />
<br />
If the strain of the hinge is causing the case to start to crack you can maybe build up a layer of reinforcement across the crack with [[Glossary:Epoxy|epoxy]] glue, or glue a piece of an old circuit board (with the components removed!) across the crack.<br />
<br />
In addition to epoxy, you may be able to find an inventive way of using [[Sticky_Stuff#Thermoplastics|thermoplastics]] for case repairs.<br />
<br />
====Replacing the screen====<br />
[[File:Opening_a_laptop_screen.jpg|180px|thumb|left|Opening a laptop screen.]]<br />
A laptop screen can get cracked though physical abuse, or may become faulty, for example showing horizontal or vertical bars across the screen. There are two options: either you can change just the [[Glossary:LCD|LCD]] display panel or you can replace the entire laptop lid with a spare, probably taken from a scrap laptop of the same model. Which you choose may depend on availability of spares, ease of disassembly of the laptop, and whether the existing lid itself is damaged and in need of replacement.<br />
<br />
Replacement of the the entire lid will require a fairly extensive disassembly, but don't be daunted! In addition to the screen data cable there may be another cable for the screen backlight, probably two for the WiFi antennae and another for the webcam, if fitted.<br />
<br />
Replacing just the LCD panel may be easier. Typically there will be a couple of screws securing the bezel, with adhesive covers hiding their heads for cosmetic purposes. After removing these, the bezel can be unclipped from the shell of the lid using a prying tool. The screws holding the LCD panel in the shell will now be revealed, and removing these allows the panel to be carefully angled forwards enabling you to disconnect the data cable.<br />
<br />
<br />
====Replacing or upgrading the processor====<br />
In most traditional clamshell laptops the processor is in a socket rather than soldered to the motherboard, and in principle, can be fairly easily replaced. You might want to do that if you believe that a faulty processor is causing frequent crashes, though it would be hard to make that diagnosis with any level of confidence. You could perhaps fit a slightly faster processor to bring it up to the specification of a more powerful variant of the same model of laptop but it's doubtful whether the effort and expense would be worth the benefit.<br />
<br />
The heat pipe and cooling grill are permanently attached to the heatsink, and this can be detached from the processor by removing the screws or clips that hold it in place. A lever or quarter-turn screw will then release the processor from its zero insertion force socket. It's critical that all the old heatsink paste is cleaned off and new applied exactly as recommended otherwise the processor is liable to overheat.<br />
<br />
==Reusing parts==<br />
If you're scrapping a laptop there are several parts that may be worth saving for reuse or repurposing.<br />
<br />
===RAM===<br />
It may well be worth saving the RAM for use to upgrade another laptop, though the older it is the less likely it is that you will ever find a use for it. Why not pool your RAM with your fellow repairers?<br />
<br />
===WiFi card===<br />
This might be worth saving if you are ever faced with a laptop which won't reliably connect to the owner's router.<br />
<br />
===Hard disk===<br />
[[File:USB_HD_enclosure.jpg|180px|thumb|right|A USB hard disk enclosure.]]<br />
This is probably the easiest. For a modest sum you can obtain a USB enclosure for a hard disk allowing you to use it as an external USB disk for backup or offline storage. Having removed the hard disk from the laptop it will often still be in a laptop-specific carrier. This is removed simply by undoing two screws on each side. The hard disk will now fit directly in the new enclosure.<br />
<br />
[[File:CD_bay_enclosure.jpg|180px|thumb|left|A CD/DVD drive bay enclosure for a hard disk.]]<br />
If you find that these days you hardly ever need a CD/DVD drive and could manage just as well with an external one, you may be able to get a caddy for a hard disk to fit in your CD/DVD drive bay. If you've upgraded your hard disk to an SSD with less capacity then you could use this to house your old hard disk. The heights of the of the drive bay, the caddy to fit it and the hard disk to go in it are the only important things to check.<br />
<br />
===CD/DVD drive===<br />
[[File:CD_drive_enclosure.jpg|180px|thumb|right|An enclosure for a laptop CD/DVD dive.]]<br />
Similar USB enclosures can be obtained for a CD/DVD drive. Just as with a CD/DVD drive bay enclosure for a hard disk, you will need to ensure the height of the enclosure is sufficient for the CD/DVD drive. The drive will probably have a laptop-specific bezel which can be unclipped and replaced by one that comes with the enclosure.<br />
<br />
CD/DVD drives often take more current than a USB socket will supply, and so the enclosure may have an extra USB lead to plug into a second USB socket for additional power.<br />
<br />
===Screen===<br />
[[File:Repurposed_screen.jpg|180px|thumb|left|A repurposed laptop screen.]]<br />
If the laptop has a good high resolution screen it may be worth saving. You can obtain a controller for around £20 to turn it into an external monitor for your new laptop or to use with a Raspberry Pi. These controllers are often generic parts which the supplier must configure for your specific screen. The part number should be printed on the back of the screen and it's essential that you obtain a controller for that precise part number, including any suffixes or version numbers, otherwise there's a strong chance it won't work.<br />
<br />
You can keep the screen in its existing laptop lid or make up a picture frame for it, and maybe laser-cut a box for the controller.<br />
<br />
Alternatively, you can take the LCD assembly out and separate the LCD panel from the backlight. The backlight can then be used as a lightbox. With bigger screens such as flat screen TVs you can use the backlight for illumination. The way the light is concentrated in a direction perpendicular to the screen can give the impression of light coming through a window or skylight, as shown in this [https://youtu.be/8JrqH2oOTK4 Youtube video].<br />
<br />
===Camera===<br />
If the laptop has a camera in the top of the screen, you may be able to make a USB webcam out of it. The camera chip itself is usually mounted on a small circuit board which also contains a USB interface chip. The cable connecting this through the hinge to the mainboard will contain 4 or 5 coloured wires, the colours typically being the same standard colors as a USB cable. All you have to do is match them up with the wires inside a scap USB cable, and you're done.<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Yes,_you_can_fix_your_laptop!&diff=3533Yes, you can fix your laptop!2020-05-27T08:51:33Z<p>Pleriche: /* Screen */</p>
<hr />
<div>Fixing a laptop isn't nearly as scary as you might think. Here's what you can hope to do and how to set about doing it.<br />
<br />
==Summary==<br />
Most traditional "clamshell" laptops are relatively straightforward to disassemble and repair. Although they don't contain as many standard parts as a desktop computer, most parts can be replaced and some can be upgraded.<br />
<br />
If you decide a laptop is beyond repair there may still be the possibility of reusing a few of the components.<br />
<br />
Unfortunately, newer ultra-thin laptops offer less scope, and a few are virtually unrepairable.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Backup important data before you start. Things don't often go badly wrong, but why take the risk?<br />
<br />
::Before starting work, disconnect the power and remove a user-replaceable battery if there is one.<br />
<br />
::Consider whether you need to take [[Electrostatic Discharge Precautions|antistatic]] precautions. Brushes and vacuum cleaners can create static.<br />
<br />
==Before you start==<br />
For any but the most basic tasks, the first thing to do is to search for an online repair or disassembly guide or video. One of the best places to look is iFixit.com but a search engine will give others. Many laptops come in several variants so if you can't find your precise model then look through the guides for the closest match and it should give you a very good idea how to proceed.<br />
<br />
The only tools you will normally need are a set of small screwdrivers and a prying tool - a thin-bladed tool for prying open the clips which very often hold the case together. The iFixit [https://eustore.ifixit.com/en/Tools/Prying-Opening/Jimmy.htm Jimmy] is ideal. A knife, preferably with a thin blade and a round end and not too sharp will do if you have nothing else.<br />
<br />
For the intermediate level tasks you will also need a means of organising the screws. Pill boxes are an excellent choice but egg boxes will do. Be sure to record for each pill box or egg box compartment which disassembly step the screws came from. You think you'll remember, but believe me, you won't!<br />
<br />
Another good solution is to stick the screws to a sheet of paper with Blu-tac. So long as you only use half the sheet you can fold it over in order to keep the screws reasonably safe if you need to put it aside and come back later to complete the job. Write the disassembly step or where the screws came from next to each blob of Blu-tac. On reassembly, if Blu-tac sticks to the screw threads you can remove it by dabbing them on a piece of clean Blu-tac; Blu-tac sticks to Blu-tac better than it sticks to screws.<br />
<br />
Sometimes you will find arrows against some of the screws on the base of a laptop or on a motherboard. These are the screws to undo; leave any others, at least for the time being.<br />
<br />
If the laptop case won't come apart, remember, there's always one more screw! If for instance you can ease it apart by a centimetre or two on the left side but only by a few millimetres on the right, the remaining screw is almost certainly close to the right hand side.<br />
<br />
On reassembly you may sometimes find at a certain step you have more holes than screws to go in them. This will be because the other holes are for screws to hold the case on. If you put screws in those holes now you'll have a problem later. A good disassembly guide will make this clear.<br />
<br />
==What can you do?==<br />
In the case of traditional clamshell laptops, many are similar in construction, though some you open from the top and others from the bottom. More modern ultra-thin and convertible laptops tend to be simpler in construction but not necessarily easier to take apart. In particular:<br />
* Some are glued together and almost impossible to repair whereas with others simply removing the back gives access to the motherboard and main components.<br />
* Batteries tend not to be user-replaceable but built-in. They are custom assemblies shaped to fit within the laptop case rather than made out of standard cylindrical lithium cells.<br />
* The keyboard may be built into the case top and the [[Glossary:RAM|RAM]] soldered directly to the motherboard making them much harder to replace.<br />
<br />
The various tasks you can undertake are listed below, grouped roughly according to difficulty for a typical clamshell laptop. That said, what's easy on one laptop can require extensive disassembly on another, or vice versa.<br />
<br />
===Easy===<br />
<br />
====Battery removal or replacement====<br />
[[File:Battery_removal.jpg|180px|thumb|right|Removing a laptop battery.]]<br />
<br />
Many laptops allow you to remove the battery simply by releasing a couple of catches. Often, one is spring loaded. With newer ultra-thin and convertible laptops you will probably need to remove the case back. Look for an online guide to show you how.<br />
<br />
Unfortunately, sourcing replacement batteries is something of a minefield. Genuine manufacturer's batteries tend to be outrageously expensive, and if they have been sitting on a shelf for several years they may already be losing capacity. After market batteries may or may not be worth the money and may even be pulled from scrap laptops. Some are re-manufactured using fresh cells, which is fine so long as the smart controller within them has been reset. Other things being equal, a mid-price battery could be a good choice. To protect yourself:<br />
* Check the vendor's warranty period and returns policy.<br />
* Check the vendor's reputation and other purchasers' experience on independent review sites such as Trustpilot. Be aware that favourable reviews can be bought.<br />
* When the battery arrives, check whether you are required to register a warranty for it to be valid, though under consumer law this should not be necessary.<br />
<br />
Batteries for ultra-thin and convertible laptops are harder to replace and may be harder to source.<br />
<br />
====RAM replacement or upgrade====<br />
[[File:RAM removal.jpg|180px|thumb|left|Removing the RAM from a laptop.]]<br />
Upgrading your [[Glossary:RAM|RAM]] (main working memory) is probably the easiest upgrade you can do, and at the same time, often one of the most effective. You can usually access the RAM slots simply by removing a service cover on the base. Two clips, one either side, hold each memory module in its slot. On replacement, ensure the memory module is seated as far as it will go in the connector before angling it down to engage the clips.<br />
<br />
If your laptop has a 32 bit processor or runs a 32 bit version of Windows and has less than 4GB of RAM, then upgrading to 4GB (the maximum it can use) is generally well worth while and relatively inexpensive.<br />
<br />
(If you're not sure whether your laptop is 32 or 64 bit, press the Windows key and "R" and type msinfo32. Press Return. A complete run-down of your computer's resources will be given.)<br />
<br />
Upgrading a 64 bit laptop beyond 4GB may well be worthwhile, particularly if you do graphics, video or audio editing, or commonly have many browser tabs open.<br />
<br />
<br />
====Replacement of a damaged or faulty keyboard====<br />
[[File:Keyboard_removal.jpg|180px|thumb|right|Removing a laptop keyboard.]]<br />
Many people put up with a damaged or unreliable keyboard without realising just how cheap and easy it might be to replace.<br />
<br />
Search for an online guide. Quite commonly, all you have to do is release a series of catches along one long edge of the keyboard in order to lift it out. A ribbon cable will still be connecting it to the motherboard, and you can release this by carefully lifting or releasing a clamping bar. (See [[Connectors#Ribbon_connectors|Ribbon Connectors]].)<br />
<br />
On some laptops the keyboard is additionally held in place by one or more screws which you have to unscrew from the bottom of the case, or hidden under a snap-on bezel between the keyboard and screen. On others, the keyboard is integral with the case top, but still not that hard to remove.<br />
<br />
Replacement keyboards for most models of laptop are available online for around £20. Make sure you get one for your exact model. Also, make sure you get one with the right national keyboard layout, otherwise you may find some keys in unfamiliar places.<br />
<br />
<br />
====Hard disk replacement or upgrade====<br />
[[File:Hard_disk_removal.jpg|180px|thumb|left|Removing a laptop hard disk.]]<br />
Very often you can access the [[Glossary:Hard Disk|hard disk]] simply by removing a service cover on the base. On some laptops, particularly consumer grade ones, a first level of disassembly may be required.<br />
<br />
[[SSD Migration and Troubleshooting|Replacing a hard disk with a solid state disk]] is probably the most effective way of injecting new life into an old laptop. But if it's running slowly because of unwanted software, pop-ups or viruses then you should tackle those first.<br />
<br />
If you are running out of storage space then fitting a larger hard disk is easy. Laptop hard disks are highly standardised in size though they do come in several different heights. If you are fitting one with a higher capacity, check that it's no thicker than the old one.<br />
<br />
If you're happy to reinstall your [[Glossary:Operating System|operating system]] on your new disk then that's the easiest way to go. To copy your existing system you will need appropriate disk cloning software. Copying a hard disk to a smaller SSD requires an extra step to shrink the file system.<br />
<br />
<br />
====CD/DVD drive replacement====<br />
[[File:Optical_disk_removal.jpg|180px|thumb|right|Removing a laptop CD/DVD drive.]]<br />
A faulty CD/DVD drive is easily replaced, or you might wish to replace it with a better one, or a Blu-ray drive. They are all a standard size, but come in a couple of different heights.<br />
<br />
The CD/DVD drive normally just slides into the laptop shell, but it's retained by a screw at the back, somewhere around the middle of the laptop. Quite often you will be able to remove this screw with no more disassembly than removing the service cover on the bottom.<br />
<br />
The drive will usually have a bezel which is shaped and styled to match the laptop, and this can be unclipped and transferred to a new drive.<br />
<br />
<br />
===Just a little harder===<br />
<br />
====Replacing the WiFi adapter====<br />
[[File:WiFi_adapter_removal.jpg|180px|thumb|left|Removing a laptop WiFi adapter.]]<br />
WiFi is supposed to be standardised, but nevertheless a particular brand of adapter will sometimes refuse to work reliably with a particular router. The WiFi adapter is often a small easily replaceable board.<br />
<br />
It may be very easily accessible along with the RAM and the hard disk under a service cover on the bottom of the case. Gently lift off the two antenna connectors and remove one or two screws holding it in place, then remove the adapter from the socket it fits in, which similar to a RAM socket but smaller.<br />
<br />
On some laptops the WiFi adapter may not be quite so easily accessed, requiring a first level of disassembly.<br />
<br />
<br />
====Cleaning the fan====<br />
After a few years it's very common for the fan (or more usually the cooling fins) to get clogged with matted dust. This will cause the laptop to overheat, the fan to run continuously and perhaps noisily, and may cause the laptop to crash.<br />
<br />
[[Clean_up!_Cool down!|Cleaning the fan]] is not difficult but usually requires fairly extensive disassembly of the laptop, which may be daunting. Don't be put off. Given a good disassembly guide, this is perfectly doable.<br />
<br />
<br />
====Replacing the power connector====<br />
A damaged power connector which no longer connects reliably is not uncommon. In many cases it's replaceable. As with cleaning the fan, this is likely to require fairly extensive disassembly but often, the power connector itself is easily removed from the case and simply plugs into the motherboard via a flying lead.<br />
<br />
If you're unlucky you may find the power connector is soldered directly to the motherboard, in which case you will need to be confident with a soldering iron to replace it. Or you might find the problem is that the laptop case is broken around the power connector so that you can't push the plug fully home.<br />
<br />
<br />
====Replacing the backup battery====<br />
[[File:Laptop_backup_battery.jpg|180px|thumb|right|A laptop backup battery.]]<br />
All laptops contain a small backup battery, often (for historical reasons) erroneously called the CMOS battery. This keeps the clock running when neither mains power nor a main battery are present. (Removing this battery will not reset the BIOS settings and BIOS password as sometimes thought. These have been held in [[Glossary:Flash|flash]] memory similar to a memory stick in all computers since about the 1990's.)<br />
<br />
This battery is usually a non-rechargeable lithium coin cell, or sometimes a rechargeable nickel battery in a plastic sleeve. Either way it may fail after maybe 10 years or more causing the computer to lose its time and date on loss of power. If you're lucky, it will be on a flying lead connected to the motherboard via a miniature plug and socket, or it might be a coin cell in a socket. Otherwise it could be soldered in and a certain level of disassembly may be required to access it. If you can't get hold of an identical replacement, provided it's the same voltage and the same chemistry it should be fine. If you need to improvise at all, make sure you get a "tagged" battery having tags spot-welded to it which you can solder to. It's not possible to solder directly to a battery of any type without damaging it.<br />
<br />
===More difficult===<br />
<br />
====Fixing a broken hinge====<br />
A broken laptop hinge is a very common problem. Unfortunately it's nearly always the plastic the hinge is attached to that is broken rather than the hinge itself. The hinge screws usually screw into brass bushes set in plastic pillars which are part of the case moulding. These pillars are simply not strong enough in many laptops and break off.<br />
<br />
Repair can be quite difficult. If you glue the plastic pillar back to the case it has to be positioned very precisely if it's not to be strained when you screw the hinge back to it. If possible, it's best to glue the pillar back to the case, still attached to the hinge, in order to position it accurately. Rapid setting two part [[Sticky_Stuff#Epoxy|epoxy glue]] is best, and once it's lightly secured, build up more epoxy around the break to reinforce it.<br />
<br />
An alternative approach is given in this [https://www.ifixit.com/Guide/Disassembling+Laptop+Toshiba+Satellite+P855+P850+plus+Hinge+FIX/36744 iFixit guide] using wall plugs and multi-purpose or wood screws.<br />
<br />
====Cracked casing====<br />
If the laptop has been dropped the case may be cracked or broken. A cover or bezel or the clips that retain it may be broken, causing it to keep falling off. This may be challenging to repair properly. The simple, if somewhat inelegant solution is to secure it with sticky tape. Black PVC tape will probably match the case. Gaffer or Duct tape will be stronger.<br />
<br />
If the strain of the hinge is causing the case to start to crack you can maybe build up a layer of reinforcement across the crack with [[Glossary:Epoxy|epoxy]] glue, or glue a piece of an old circuit board (with the components removed!) across the crack.<br />
<br />
In addition to epoxy, you may be able to find an inventive way of using [[Sticky_Stuff#Thermoplastics|thermoplastics]] for case repairs.<br />
<br />
====Replacing the screen====<br />
[[File:Opening_a_laptop_screen.jpg|180px|thumb|left|Opening a laptop screen.]]<br />
A laptop screen can get cracked though physical abuse, or may become faulty, for example showing horizontal or vertical bars across the screen. There are two options: either you can change just the [[Glossary:LCD|LCD]] display panel or you can replace the entire laptop lid with a spare, probably taken from a scrap laptop of the same model. Which you choose may depend on availability of spares, ease of disassembly of the laptop, and whether the existing lid itself is damaged and in need of replacement.<br />
<br />
Replacement of the the entire lid will require a fairly extensive disassembly, but don't be daunted! In addition to the screen data cable there may be another cable for the screen backlight, probably two for the WiFi antennae and another for the webcam, if fitted.<br />
<br />
Replacing just the LCD panel may be easier. Typically there will be a couple of screws securing the bezel, with adhesive covers hiding their heads for cosmetic purposes. After removing these, the bezel can be unclipped from the shell of the lid using a prying tool. The screws holding the LCD panel in the shell will now be revealed, and removing these allows the panel to be carefully angled forwards enabling you to disconnect the data cable.<br />
<br />
<br />
====Replacing or upgrading the processor====<br />
In most traditional clamshell laptops the processor is in a socket rather than soldered to the motherboard, and in principle, can be fairly easily replaced. You might want to do that if you believe that a faulty processor is causing frequent crashes, though it would be hard to make that diagnosis with any level of confidence. You could perhaps fit a slightly faster processor to bring it up to the specification of a more powerful variant of the same model of laptop but it's doubtful whether the effort and expense would be worth the benefit.<br />
<br />
The heat pipe and cooling grill are permanently attached to the heatsink, and this can be detached from the processor by removing the screws or clips that hold it in place. A lever or quarter-turn screw will then release the processor from its zero insertion force socket. It's critical that all the old heatsink paste is cleaned off and new applied exactly as recommended otherwise the processor is liable to overheat.<br />
<br />
==Reusing parts==<br />
If you're scrapping a laptop there are several parts that may be worth saving for reuse or repurposing.<br />
<br />
===RAM===<br />
It may well be worth saving the RAM for use to upgrade another laptop, though the older it is the less likely it is that you will ever find a use for it. Why not pool your RAM with your fellow repairers?<br />
<br />
===WiFi card===<br />
This might be worth saving if you are ever faced with a laptop which won't reliably connect to the owner's router.<br />
<br />
===Hard disk===<br />
[[File:USB_HD_enclosure.jpg|180px|thumb|right|A USB hard disk enclosure.]]<br />
This is probably the easiest. For a modest sum you can obtain a USB enclosure for a hard disk allowing you to use it as an external USB disk for backup or offline storage. Having removed the hard disk from the laptop it will often still be in a laptop-specific carrier. This is removed simply by undoing two screws on each side. The hard disk will now fit directly in the new enclosure.<br />
<br />
[[File:CD_bay_enclosure.jpg|180px|thumb|left|A CD/DVD drive bay enclosure for a hard disk.]]<br />
If you find that these days you hardly ever need a CD/DVD drive and could manage just as well with an external one, you may be able to get a caddy for a hard disk to fit in your CD/DVD drive bay. If you've upgraded your hard disk to an SSD with less capacity then you could use this to house your old hard disk. The heights of the of the drive bay, the caddy to fit it and the hard disk to go in it are the only important things to check.<br />
<br />
===CD/DVD drive===<br />
[[File:CD_drive_enclosure.jpg|180px|thumb|right|An enclosure for a laptop CD/DVD dive.]]<br />
Similar USB enclosures can be obtained for a CD/DVD drive. The drive will probably have a laptop-specific bezel which can be unclipped and replaced by one that comes with the enclosure.<br />
<br />
CD/DVD drives often take more current than a USB socket will supply, and so the enclosure may have an extra USB lead to plug into a second USB socket for additional power.<br />
<br />
===Screen===<br />
[[File:Repurposed_screen.jpg|180px|thumb|left|A repurposed laptop screen.]]<br />
If the laptop has a good high resolution screen it may be worth saving. You can obtain a controller for around £20 to turn it into an external monitor for your new laptop or to use with a Raspberry Pi. These controllers are often generic parts which the supplier must configure for your specific screen. The part number should be printed on the back of the screen and it's essential that you obtain a controller for that precise part number, including any suffixes or version numbers, otherwise there's a strong chance it won't work.<br />
<br />
You can keep the screen in its existing laptop lid or make up a picture frame for it, and maybe laser-cut a box for the controller.<br />
<br />
Alternatively, you can take the LCD assembly out and separate the LCD panel from the backlight. The backlight can then be used as a lightbox. With bigger screens such as flat screen TVs you can use the backlight for illumination. The way the light is concentrated in a direction perpendicular to the screen can give the impression of light coming through a window or skylight, as shown in this [https://youtu.be/8JrqH2oOTK4 Youtube video].<br />
<br />
===Camera===<br />
If the laptop has a camera in the top of the screen, you may be able to make a USB webcam out of it. The camera chip itself is usually mounted on a small circuit board which also contains a USB interface chip. The cable connecting this through the hinge to the mainboard will contain 4 or 5 coloured wires, the colours typically being the same standard colors as a USB cable. All you have to do is match them up with the wires inside a scap USB cable, and you're done.<br />
<br />
[[Category:General]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Sticky_Stuff&diff=3532Sticky Stuff2020-05-21T09:50:33Z<p>Pleriche: /* Sellotape and Scotch Tape */ Added heat-shrink sleeving</p>
<hr />
<div>There are many different type of adhesives, glues and sticky tapes, each with its own strengths and weaknesses. Here you can learn which would be best for particular repair.<br />
<br />
==Summary==<br />
When things fall part there are various types of glue and sticky tape that you can use to stick them back together again, but different ones are good for different things. This page will help you choose the right one.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Broken mains electrical items repaired with adhesive and/or sticky tape will necessarily fail the visual inspection part of a PAT electrical safety test. If you decide on such a repair (at your own risk) you should at least ensure that any glue is supported by strong tape such as gaffer tape wrapped completely around the item, with a good overlap.<br />
<br />
::Some types of glue may be highly flammable, or cause skin irritation or give off unhealthy fumes.<br />
<br />
==Types of Glue==<br />
There are lots of different types of glue. The first few below are the most useful in a Restart situation but others may come in handy for general repairs or for making stuff.<br />
<br />
Always read the instructions or you may not get satisfactory results, and might be unaware of any potential hazards.<br />
<br />
===Superglue===<br />
[[File:Warning03.png|30px|left]]<br />
::Superglue will stick your fingers together instantly. You may find it rather embarrassing to have to go to A&E to get them unstuck.<br />
<br />
Superglue will make a very strong join provided the surfaces to be mated fit together very closely, but it's not so good at filling gaps. Buy it in small tubes, try to clear the nozzle after use, and make sure you put the lid on tight as otherwise it will set solid.<br />
<br />
If you do need to fill a gap then you can use the superglue and baking powder trick. Place a little baking powder in the gap - only as much as you can soak with one drop of superglue, then add the drop of superglue. You can repeat the process as often as needed to fill a larger gap. It will set in a very few minutes into a very hard and tough solid.<br />
<br />
===Epoxy===<br />
Epoxy glue comes in 2 separate tubes. Squeeze the same amount from each tube and mix well. Be sure to put the right lid back on the right tube, or you'll never get them off again!<br />
<br />
Epoxy glue is very strong and sticks to most things. Although it's best if the mating surfaces fit well together, you can use it to fill gaps or you can build it up around a join to add strength.<br />
<br />
Rapid epoxy sets in a few minutes and so is very useful, though it takes longer to achieve full strength.<br />
<br />
===Hot Melt===<br />
Hot melt glue comes in sticks which you have to feed into a glue gun. Cheap glue guns are available for just a few pounds. Apply the glue and join the parts together immediately. The glue will set in a few seconds as it cools but will take a little longer to gain full strength.<br />
<br />
Hot melt glue remains flexible after it has set and so is good for repairing flexible things, like sticking the sole back on a shoe. Where a wire is soldered to a circuit board a blob of hot melt glue is very good for preventing the wire from flexing and breaking at the solder joint.<br />
<br />
===PVA Glue===<br />
This works well with porous materials such as paper, wood and cloth. You may have first met it at a tender age as school glue. It's used in handicrafts, bookbinding, woodworking and as wallpaper adhesive. A screwed and glued joint in woodworking is very strong.<br />
<br />
===Vinyl Adhesive===<br />
This is good for sticking PVC as it consists of PVC dissolved in a solvent. This partially dissolves the surfaces to be joined, formng a weld as it sets.<br />
<br />
===Glass Bond===<br />
This is a UV-cured adhesive which is good for sticking glass, transparent acrylic or metal to glass or acrylic. To cure it you can use a UV torch or bank note checker, available cheaply on eBay. Alternatively you can simply leave it in sunlight, though it will take considerably longer.<br />
<br />
===Polystyrene Glue===<br />
Mainly used for assembling "Airfix" and similar plastic models, but also for paper.<br />
<br />
===Silicone Glue===<br />
Silicone filler is most commonly used for sealing around bathroom and kitchen fittings, and around window frames, but can also be used as an adhesive. It remains flexible after it has set but is not especially strong, and surfaces need to be clean and dry. You may see its use in consumer electronics where a blob has been applied to retain a flying lead in position.<br />
<br />
[[Sticky_Stuff#Sugru|Sugru]] is a type of silicone, described later.<br />
<br />
Once opened, a tube of silicone adhesive is difficult to effectively seal. After a few months you may find the nozzle if not the whole tube has set solid.<br />
<br />
===Flour and water paste===<br />
Mix a little flour with water to make a moist spreadable paste. This makes a surprisingly good glue for paper, card and fabric if you have nothing else to hand, and is child-safe.<br />
<br />
==Sticky Tapes==<br />
<br />
===PVC Tape===<br />
PVC insulating tape is good for wrapping around exposed wires and electrical connections, however, it should never be use as the sole protection in the case of mains (or higher) voltages. If two wires are simply twisted together, heat may be generated when a current flows and this could melt the tape. (Use solder or a crimped or screw-secured connection - see [[Connecting and joining wires]].)<br />
<br />
PVC tape sticks reasonably well but it's stretchy and not especially strong, so shouldn't be used simply for fixing.<br />
<br />
===Gaffer Tape and Duct Tape===<br />
These are very strong tapes used for holding things together. Gaffer tape has a fabric backing and is designed to be removable; it is often used to tape cables down to avoid trip hazards or to conceal them on stage. Duct tape has a plastic-coated fabric back and is designed to stick permanently: it is used for all sorts of repairs and is waterproof and very durable. The two are similar, are often confused and are interchangeable for many uses.<br />
<br />
These tapes are very versatile. It's said that Mission Control knew they had a chance of saving the Apollo 13 crew when they realised they had duct tape on board.<br />
<br />
===Self-amalgamating Tape===<br />
This isn't strictly adhesive, but when wrapped around an electrical junction or low pressure water pipe the layers fuse together seamlessly.<br />
<br />
===Sellotape and Scotch Tape===<br />
These should only be used for paper and parcels.<br />
<br />
===Heat-shrink Sleeving===<br />
A little different though useful in some of the same situations is heat-shrink sleeving. This comes in various diameters and shrinks to half the diameter when heated. Slipping a piece over a wire join is much better than using PVC tape. You can shrink it (ideally) with a hot air gun, or if you don't have one to hand, holding it very close over the barrel of a soldering iron will do it, but you need to be careful not to let it touch.<br />
<br />
==Conductive Sticky Stuff==<br />
<br />
===Bare Conductive electric paint===<br />
[http://www.bareconductive.com/ Bare Conductive] is an electrically conductive paint which you may be able to use to bridge a broken connection. It has a much higher resistance than copper or solder and so isn't suitable where a low resistance connection is required or where it must carry more than a few mA. It should be fine, however, for connections to an LCD, or to the momentary-contact push buttons on nearly all modern electronic equipment.<br />
<br />
A slight problem with it is that once opened, the dispenser dries out over a period of months. You may be able to rejuvenate it if you can unblock the nozzle and introduce a little plain water, then shake vigorously. A hypodermic syringe would be ideal for this.<br />
<br />
===Conductive Silver Paint===<br />
If you need a low resistance join for example to mend a broken circuit board trace then conductive silver paint may well do the job, although it's expensive. Like bare Conductive, once opened it dries out quite quickly, and being solvent based can't so easily be restored.<br />
<br />
==Other Sticky Stuff==<br />
<br />
===Sugru===<br />
Sugru comes in sachets and initially has a putty-like consistency but cures to a synthetic rubber. Excellent for adding protection and strain relief to a low voltage cable (such as a headphone lead) where the outer insulation is starting to crack on its entry to the plug. The website [http://www.sugru.com www.sugru.com] gives hundreds of other examples of its use. It comes in black or white and several bright colours.<br />
<br />
A drawback is that part used sachets can't be resealed and will very quickly go off, and unused sachets have a limited shelf life. This can be extended somewhat by keeping them in the fridge.<br />
<br />
===Thermoplastics===<br />
Polymorph consists of granules which turn soft when heated to 62 degrees centigrade, then harden again when they cool. The Register [http://m.theregister.co.uk/2011/12/31/christmas_repairs/ described] it as 'the stuff of the gods, or would be if it had been around when the gods were choosing a construction material.'<br />
<br />
Formcard is essentially the same except that it comes in convenient credit card sized pieces. The idea is that you can easily keep one with you for use whenever you might need it. It can be softened in hot water as required and then can be moulded for a variety of uses before it sets hard on cooling. It was launched in a [https://www.kickstarter.com/projects/formcard/formcard-melt-mould-make-mend Kickstarter] campaign in late 2015 and is now available from [http://www.formcard.com/ the inventors website].<br />
<br />
===Modelling Clay===<br />
There are several types of modelling clay, mostly used for making rather than repairing. Polymer clay can be cured by heating to a modest temperature of 130⁰C for 15 minutes and doesn't shrink or change shape in the process. It can be obtained from hobby, craft and art stores.<br />
<br />
===Milliput===<br />
[http://www.milliput.com Milliput] is a two-part, cold setting, non-shrinking epoxy putty which can be used for repairs on many types of materials including metals, plastics, masonry, wood, glass and ceramics.<br />
<br />
==How to remove glue==<br />
Sometimes your problem might actually be to unglue something, either because it wasn't glued properly or because you need to disassemble the item for repair. Different glues will respond to different solvents, but two of the best for difficult cases are:<br />
*Acetone (or nail polish remover)<br />
*Proprietary glue removers (search online) especially those advertised for removing super glue.<br />
<br />
The latter often contain heterocyclic ketone, which is a powerful glue remover. (Acetone is a ketone, but not a heterocyclic one.)<br />
<br />
Be aware that any solvents may irritate sensitive skin or discolour the glued item, especially fabrics.<br />
<br />
==External links==<br />
* [https://therestartproject.org/podcast/materials-hack-fix Our Restart Radio show "Materials we use to hack and fix"]<br />
<br />
[[Category:Skills]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Sticky_Stuff&diff=3531Sticky Stuff2020-05-21T09:37:15Z<p>Pleriche: /* Silicone Glue */ Oops!</p>
<hr />
<div>There are many different type of adhesives, glues and sticky tapes, each with its own strengths and weaknesses. Here you can learn which would be best for particular repair.<br />
<br />
==Summary==<br />
When things fall part there are various types of glue and sticky tape that you can use to stick them back together again, but different ones are good for different things. This page will help you choose the right one.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Broken mains electrical items repaired with adhesive and/or sticky tape will necessarily fail the visual inspection part of a PAT electrical safety test. If you decide on such a repair (at your own risk) you should at least ensure that any glue is supported by strong tape such as gaffer tape wrapped completely around the item, with a good overlap.<br />
<br />
::Some types of glue may be highly flammable, or cause skin irritation or give off unhealthy fumes.<br />
<br />
==Types of Glue==<br />
There are lots of different types of glue. The first few below are the most useful in a Restart situation but others may come in handy for general repairs or for making stuff.<br />
<br />
Always read the instructions or you may not get satisfactory results, and might be unaware of any potential hazards.<br />
<br />
===Superglue===<br />
[[File:Warning03.png|30px|left]]<br />
::Superglue will stick your fingers together instantly. You may find it rather embarrassing to have to go to A&E to get them unstuck.<br />
<br />
Superglue will make a very strong join provided the surfaces to be mated fit together very closely, but it's not so good at filling gaps. Buy it in small tubes, try to clear the nozzle after use, and make sure you put the lid on tight as otherwise it will set solid.<br />
<br />
If you do need to fill a gap then you can use the superglue and baking powder trick. Place a little baking powder in the gap - only as much as you can soak with one drop of superglue, then add the drop of superglue. You can repeat the process as often as needed to fill a larger gap. It will set in a very few minutes into a very hard and tough solid.<br />
<br />
===Epoxy===<br />
Epoxy glue comes in 2 separate tubes. Squeeze the same amount from each tube and mix well. Be sure to put the right lid back on the right tube, or you'll never get them off again!<br />
<br />
Epoxy glue is very strong and sticks to most things. Although it's best if the mating surfaces fit well together, you can use it to fill gaps or you can build it up around a join to add strength.<br />
<br />
Rapid epoxy sets in a few minutes and so is very useful, though it takes longer to achieve full strength.<br />
<br />
===Hot Melt===<br />
Hot melt glue comes in sticks which you have to feed into a glue gun. Cheap glue guns are available for just a few pounds. Apply the glue and join the parts together immediately. The glue will set in a few seconds as it cools but will take a little longer to gain full strength.<br />
<br />
Hot melt glue remains flexible after it has set and so is good for repairing flexible things, like sticking the sole back on a shoe. Where a wire is soldered to a circuit board a blob of hot melt glue is very good for preventing the wire from flexing and breaking at the solder joint.<br />
<br />
===PVA Glue===<br />
This works well with porous materials such as paper, wood and cloth. You may have first met it at a tender age as school glue. It's used in handicrafts, bookbinding, woodworking and as wallpaper adhesive. A screwed and glued joint in woodworking is very strong.<br />
<br />
===Vinyl Adhesive===<br />
This is good for sticking PVC as it consists of PVC dissolved in a solvent. This partially dissolves the surfaces to be joined, formng a weld as it sets.<br />
<br />
===Glass Bond===<br />
This is a UV-cured adhesive which is good for sticking glass, transparent acrylic or metal to glass or acrylic. To cure it you can use a UV torch or bank note checker, available cheaply on eBay. Alternatively you can simply leave it in sunlight, though it will take considerably longer.<br />
<br />
===Polystyrene Glue===<br />
Mainly used for assembling "Airfix" and similar plastic models, but also for paper.<br />
<br />
===Silicone Glue===<br />
Silicone filler is most commonly used for sealing around bathroom and kitchen fittings, and around window frames, but can also be used as an adhesive. It remains flexible after it has set but is not especially strong, and surfaces need to be clean and dry. You may see its use in consumer electronics where a blob has been applied to retain a flying lead in position.<br />
<br />
[[Sticky_Stuff#Sugru|Sugru]] is a type of silicone, described later.<br />
<br />
Once opened, a tube of silicone adhesive is difficult to effectively seal. After a few months you may find the nozzle if not the whole tube has set solid.<br />
<br />
===Flour and water paste===<br />
Mix a little flour with water to make a moist spreadable paste. This makes a surprisingly good glue for paper, card and fabric if you have nothing else to hand, and is child-safe.<br />
<br />
==Sticky Tapes==<br />
<br />
===PVC Tape===<br />
PVC insulating tape is good for wrapping around exposed wires and electrical connections, however, it should never be use as the sole protection in the case of mains (or higher) voltages. If two wires are simply twisted together, heat may be generated when a current flows and this could melt the tape. (Use solder or a crimped or screw-secured connection - see [[Connecting and joining wires]].)<br />
<br />
PVC tape sticks reasonably well but it's stretchy and not especially strong, so shouldn't be used simply for fixing.<br />
<br />
===Gaffer Tape and Duct Tape===<br />
These are very strong tapes used for holding things together. Gaffer tape has a fabric backing and is designed to be removable; it is often used to tape cables down to avoid trip hazards or to conceal them on stage. Duct tape has a plastic-coated fabric back and is designed to stick permanently: it is used for all sorts of repairs and is waterproof and very durable. The two are similar, are often confused and are interchangeable for many uses.<br />
<br />
These tapes are very versatile. It's said that Mission Control knew they had a chance of saving the Apollo 13 crew when they realised they had duct tape on board.<br />
<br />
===Self-amalgamating Tape===<br />
This isn't strictly adhesive, but when wrapped around an electrical junction or low pressure water pipe the layers fuse together seamlessly.<br />
<br />
===Sellotape and Scotch Tape===<br />
These should only be used for paper and parcels.<br />
<br />
==Conductive Sticky Stuff==<br />
<br />
===Bare Conductive electric paint===<br />
[http://www.bareconductive.com/ Bare Conductive] is an electrically conductive paint which you may be able to use to bridge a broken connection. It has a much higher resistance than copper or solder and so isn't suitable where a low resistance connection is required or where it must carry more than a few mA. It should be fine, however, for connections to an LCD, or to the momentary-contact push buttons on nearly all modern electronic equipment.<br />
<br />
A slight problem with it is that once opened, the dispenser dries out over a period of months. You may be able to rejuvenate it if you can unblock the nozzle and introduce a little plain water, then shake vigorously. A hypodermic syringe would be ideal for this.<br />
<br />
===Conductive Silver Paint===<br />
If you need a low resistance join for example to mend a broken circuit board trace then conductive silver paint may well do the job, although it's expensive. Like bare Conductive, once opened it dries out quite quickly, and being solvent based can't so easily be restored.<br />
<br />
==Other Sticky Stuff==<br />
<br />
===Sugru===<br />
Sugru comes in sachets and initially has a putty-like consistency but cures to a synthetic rubber. Excellent for adding protection and strain relief to a low voltage cable (such as a headphone lead) where the outer insulation is starting to crack on its entry to the plug. The website [http://www.sugru.com www.sugru.com] gives hundreds of other examples of its use. It comes in black or white and several bright colours.<br />
<br />
A drawback is that part used sachets can't be resealed and will very quickly go off, and unused sachets have a limited shelf life. This can be extended somewhat by keeping them in the fridge.<br />
<br />
===Thermoplastics===<br />
Polymorph consists of granules which turn soft when heated to 62 degrees centigrade, then harden again when they cool. The Register [http://m.theregister.co.uk/2011/12/31/christmas_repairs/ described] it as 'the stuff of the gods, or would be if it had been around when the gods were choosing a construction material.'<br />
<br />
Formcard is essentially the same except that it comes in convenient credit card sized pieces. The idea is that you can easily keep one with you for use whenever you might need it. It can be softened in hot water as required and then can be moulded for a variety of uses before it sets hard on cooling. It was launched in a [https://www.kickstarter.com/projects/formcard/formcard-melt-mould-make-mend Kickstarter] campaign in late 2015 and is now available from [http://www.formcard.com/ the inventors website].<br />
<br />
===Modelling Clay===<br />
There are several types of modelling clay, mostly used for making rather than repairing. Polymer clay can be cured by heating to a modest temperature of 130⁰C for 15 minutes and doesn't shrink or change shape in the process. It can be obtained from hobby, craft and art stores.<br />
<br />
===Milliput===<br />
[http://www.milliput.com Milliput] is a two-part, cold setting, non-shrinking epoxy putty which can be used for repairs on many types of materials including metals, plastics, masonry, wood, glass and ceramics.<br />
<br />
==How to remove glue==<br />
Sometimes your problem might actually be to unglue something, either because it wasn't glued properly or because you need to disassemble the item for repair. Different glues will respond to different solvents, but two of the best for difficult cases are:<br />
*Acetone (or nail polish remover)<br />
*Proprietary glue removers (search online) especially those advertised for removing super glue.<br />
<br />
The latter often contain heterocyclic ketone, which is a powerful glue remover. (Acetone is a ketone, but not a heterocyclic one.)<br />
<br />
Be aware that any solvents may irritate sensitive skin or discolour the glued item, especially fabrics.<br />
<br />
==External links==<br />
* [https://therestartproject.org/podcast/materials-hack-fix Our Restart Radio show "Materials we use to hack and fix"]<br />
<br />
[[Category:Skills]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Sticky_Stuff&diff=3530Sticky Stuff2020-05-21T09:36:37Z<p>Pleriche: /* Silicone Glue */ Duplication removed</p>
<hr />
<div>There are many different type of adhesives, glues and sticky tapes, each with its own strengths and weaknesses. Here you can learn which would be best for particular repair.<br />
<br />
==Summary==<br />
When things fall part there are various types of glue and sticky tape that you can use to stick them back together again, but different ones are good for different things. This page will help you choose the right one.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Broken mains electrical items repaired with adhesive and/or sticky tape will necessarily fail the visual inspection part of a PAT electrical safety test. If you decide on such a repair (at your own risk) you should at least ensure that any glue is supported by strong tape such as gaffer tape wrapped completely around the item, with a good overlap.<br />
<br />
::Some types of glue may be highly flammable, or cause skin irritation or give off unhealthy fumes.<br />
<br />
==Types of Glue==<br />
There are lots of different types of glue. The first few below are the most useful in a Restart situation but others may come in handy for general repairs or for making stuff.<br />
<br />
Always read the instructions or you may not get satisfactory results, and might be unaware of any potential hazards.<br />
<br />
===Superglue===<br />
[[File:Warning03.png|30px|left]]<br />
::Superglue will stick your fingers together instantly. You may find it rather embarrassing to have to go to A&E to get them unstuck.<br />
<br />
Superglue will make a very strong join provided the surfaces to be mated fit together very closely, but it's not so good at filling gaps. Buy it in small tubes, try to clear the nozzle after use, and make sure you put the lid on tight as otherwise it will set solid.<br />
<br />
If you do need to fill a gap then you can use the superglue and baking powder trick. Place a little baking powder in the gap - only as much as you can soak with one drop of superglue, then add the drop of superglue. You can repeat the process as often as needed to fill a larger gap. It will set in a very few minutes into a very hard and tough solid.<br />
<br />
===Epoxy===<br />
Epoxy glue comes in 2 separate tubes. Squeeze the same amount from each tube and mix well. Be sure to put the right lid back on the right tube, or you'll never get them off again!<br />
<br />
Epoxy glue is very strong and sticks to most things. Although it's best if the mating surfaces fit well together, you can use it to fill gaps or you can build it up around a join to add strength.<br />
<br />
Rapid epoxy sets in a few minutes and so is very useful, though it takes longer to achieve full strength.<br />
<br />
===Hot Melt===<br />
Hot melt glue comes in sticks which you have to feed into a glue gun. Cheap glue guns are available for just a few pounds. Apply the glue and join the parts together immediately. The glue will set in a few seconds as it cools but will take a little longer to gain full strength.<br />
<br />
Hot melt glue remains flexible after it has set and so is good for repairing flexible things, like sticking the sole back on a shoe. Where a wire is soldered to a circuit board a blob of hot melt glue is very good for preventing the wire from flexing and breaking at the solder joint.<br />
<br />
===PVA Glue===<br />
This works well with porous materials such as paper, wood and cloth. You may have first met it at a tender age as school glue. It's used in handicrafts, bookbinding, woodworking and as wallpaper adhesive. A screwed and glued joint in woodworking is very strong.<br />
<br />
===Vinyl Adhesive===<br />
This is good for sticking PVC as it consists of PVC dissolved in a solvent. This partially dissolves the surfaces to be joined, formng a weld as it sets.<br />
<br />
===Glass Bond===<br />
This is a UV-cured adhesive which is good for sticking glass, transparent acrylic or metal to glass or acrylic. To cure it you can use a UV torch or bank note checker, available cheaply on eBay. Alternatively you can simply leave it in sunlight, though it will take considerably longer.<br />
<br />
===Polystyrene Glue===<br />
Mainly used for assembling "Airfix" and similar plastic models, but also for paper.<br />
<br />
===Silicone Glue===<br />
Silicone filler is most commonly used for sealing around bathroom and kitchen fittings, and around window frames, but can also be used as an adhesive. It remains flexible after it has set but is not especially strong, and surfaces need to be clean and dry. You may see its use in consumer electronics where a blob has been applied to retain a flying lead in position.<br />
<br />
[[Sticky_Stuff#Sugru|Sugru] is a type of silicone, described later.<br />
<br />
Once opened, a tube of silicone adhesive is difficult to effectively seal. After a few months you may find the nozzle if not the whole tube has set solid.<br />
<br />
===Flour and water paste===<br />
Mix a little flour with water to make a moist spreadable paste. This makes a surprisingly good glue for paper, card and fabric if you have nothing else to hand, and is child-safe.<br />
<br />
==Sticky Tapes==<br />
<br />
===PVC Tape===<br />
PVC insulating tape is good for wrapping around exposed wires and electrical connections, however, it should never be use as the sole protection in the case of mains (or higher) voltages. If two wires are simply twisted together, heat may be generated when a current flows and this could melt the tape. (Use solder or a crimped or screw-secured connection - see [[Connecting and joining wires]].)<br />
<br />
PVC tape sticks reasonably well but it's stretchy and not especially strong, so shouldn't be used simply for fixing.<br />
<br />
===Gaffer Tape and Duct Tape===<br />
These are very strong tapes used for holding things together. Gaffer tape has a fabric backing and is designed to be removable; it is often used to tape cables down to avoid trip hazards or to conceal them on stage. Duct tape has a plastic-coated fabric back and is designed to stick permanently: it is used for all sorts of repairs and is waterproof and very durable. The two are similar, are often confused and are interchangeable for many uses.<br />
<br />
These tapes are very versatile. It's said that Mission Control knew they had a chance of saving the Apollo 13 crew when they realised they had duct tape on board.<br />
<br />
===Self-amalgamating Tape===<br />
This isn't strictly adhesive, but when wrapped around an electrical junction or low pressure water pipe the layers fuse together seamlessly.<br />
<br />
===Sellotape and Scotch Tape===<br />
These should only be used for paper and parcels.<br />
<br />
==Conductive Sticky Stuff==<br />
<br />
===Bare Conductive electric paint===<br />
[http://www.bareconductive.com/ Bare Conductive] is an electrically conductive paint which you may be able to use to bridge a broken connection. It has a much higher resistance than copper or solder and so isn't suitable where a low resistance connection is required or where it must carry more than a few mA. It should be fine, however, for connections to an LCD, or to the momentary-contact push buttons on nearly all modern electronic equipment.<br />
<br />
A slight problem with it is that once opened, the dispenser dries out over a period of months. You may be able to rejuvenate it if you can unblock the nozzle and introduce a little plain water, then shake vigorously. A hypodermic syringe would be ideal for this.<br />
<br />
===Conductive Silver Paint===<br />
If you need a low resistance join for example to mend a broken circuit board trace then conductive silver paint may well do the job, although it's expensive. Like bare Conductive, once opened it dries out quite quickly, and being solvent based can't so easily be restored.<br />
<br />
==Other Sticky Stuff==<br />
<br />
===Sugru===<br />
Sugru comes in sachets and initially has a putty-like consistency but cures to a synthetic rubber. Excellent for adding protection and strain relief to a low voltage cable (such as a headphone lead) where the outer insulation is starting to crack on its entry to the plug. The website [http://www.sugru.com www.sugru.com] gives hundreds of other examples of its use. It comes in black or white and several bright colours.<br />
<br />
A drawback is that part used sachets can't be resealed and will very quickly go off, and unused sachets have a limited shelf life. This can be extended somewhat by keeping them in the fridge.<br />
<br />
===Thermoplastics===<br />
Polymorph consists of granules which turn soft when heated to 62 degrees centigrade, then harden again when they cool. The Register [http://m.theregister.co.uk/2011/12/31/christmas_repairs/ described] it as 'the stuff of the gods, or would be if it had been around when the gods were choosing a construction material.'<br />
<br />
Formcard is essentially the same except that it comes in convenient credit card sized pieces. The idea is that you can easily keep one with you for use whenever you might need it. It can be softened in hot water as required and then can be moulded for a variety of uses before it sets hard on cooling. It was launched in a [https://www.kickstarter.com/projects/formcard/formcard-melt-mould-make-mend Kickstarter] campaign in late 2015 and is now available from [http://www.formcard.com/ the inventors website].<br />
<br />
===Modelling Clay===<br />
There are several types of modelling clay, mostly used for making rather than repairing. Polymer clay can be cured by heating to a modest temperature of 130⁰C for 15 minutes and doesn't shrink or change shape in the process. It can be obtained from hobby, craft and art stores.<br />
<br />
===Milliput===<br />
[http://www.milliput.com Milliput] is a two-part, cold setting, non-shrinking epoxy putty which can be used for repairs on many types of materials including metals, plastics, masonry, wood, glass and ceramics.<br />
<br />
==How to remove glue==<br />
Sometimes your problem might actually be to unglue something, either because it wasn't glued properly or because you need to disassemble the item for repair. Different glues will respond to different solvents, but two of the best for difficult cases are:<br />
*Acetone (or nail polish remover)<br />
*Proprietary glue removers (search online) especially those advertised for removing super glue.<br />
<br />
The latter often contain heterocyclic ketone, which is a powerful glue remover. (Acetone is a ketone, but not a heterocyclic one.)<br />
<br />
Be aware that any solvents may irritate sensitive skin or discolour the glued item, especially fabrics.<br />
<br />
==External links==<br />
* [https://therestartproject.org/podcast/materials-hack-fix Our Restart Radio show "Materials we use to hack and fix"]<br />
<br />
[[Category:Skills]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Sticky_Stuff&diff=3529Sticky Stuff2020-05-21T09:01:00Z<p>Pleriche: /* Safety */</p>
<hr />
<div>There are many different type of adhesives, glues and sticky tapes, each with its own strengths and weaknesses. Here you can learn which would be best for particular repair.<br />
<br />
==Summary==<br />
When things fall part there are various types of glue and sticky tape that you can use to stick them back together again, but different ones are good for different things. This page will help you choose the right one.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Broken mains electrical items repaired with adhesive and/or sticky tape will necessarily fail the visual inspection part of a PAT electrical safety test. If you decide on such a repair (at your own risk) you should at least ensure that any glue is supported by strong tape such as gaffer tape wrapped completely around the item, with a good overlap.<br />
<br />
::Some types of glue may be highly flammable, or cause skin irritation or give off unhealthy fumes.<br />
<br />
==Types of Glue==<br />
There are lots of different types of glue. The first few below are the most useful in a Restart situation but others may come in handy for general repairs or for making stuff.<br />
<br />
Always read the instructions or you may not get satisfactory results, and might be unaware of any potential hazards.<br />
<br />
===Superglue===<br />
[[File:Warning03.png|30px|left]]<br />
::Superglue will stick your fingers together instantly. You may find it rather embarrassing to have to go to A&E to get them unstuck.<br />
<br />
Superglue will make a very strong join provided the surfaces to be mated fit together very closely, but it's not so good at filling gaps. Buy it in small tubes, try to clear the nozzle after use, and make sure you put the lid on tight as otherwise it will set solid.<br />
<br />
If you do need to fill a gap then you can use the superglue and baking powder trick. Place a little baking powder in the gap - only as much as you can soak with one drop of superglue, then add the drop of superglue. You can repeat the process as often as needed to fill a larger gap. It will set in a very few minutes into a very hard and tough solid.<br />
<br />
===Epoxy===<br />
Epoxy glue comes in 2 separate tubes. Squeeze the same amount from each tube and mix well. Be sure to put the right lid back on the right tube, or you'll never get them off again!<br />
<br />
Epoxy glue is very strong and sticks to most things. Although it's best if the mating surfaces fit well together, you can use it to fill gaps or you can build it up around a join to add strength.<br />
<br />
Rapid epoxy sets in a few minutes and so is very useful, though it takes longer to achieve full strength.<br />
<br />
===Hot Melt===<br />
Hot melt glue comes in sticks which you have to feed into a glue gun. Cheap glue guns are available for just a few pounds. Apply the glue and join the parts together immediately. The glue will set in a few seconds as it cools but will take a little longer to gain full strength.<br />
<br />
Hot melt glue remains flexible after it has set and so is good for repairing flexible things, like sticking the sole back on a shoe. Where a wire is soldered to a circuit board a blob of hot melt glue is very good for preventing the wire from flexing and breaking at the solder joint.<br />
<br />
===PVA Glue===<br />
This works well with porous materials such as paper, wood and cloth. You may have first met it at a tender age as school glue. It's used in handicrafts, bookbinding, woodworking and as wallpaper adhesive. A screwed and glued joint in woodworking is very strong.<br />
<br />
===Vinyl Adhesive===<br />
This is good for sticking PVC as it consists of PVC dissolved in a solvent. This partially dissolves the surfaces to be joined, formng a weld as it sets.<br />
<br />
===Glass Bond===<br />
This is a UV-cured adhesive which is good for sticking glass, transparent acrylic or metal to glass or acrylic. To cure it you can use a UV torch or bank note checker, available cheaply on eBay. Alternatively you can simply leave it in sunlight, though it will take considerably longer.<br />
<br />
===Polystyrene Glue===<br />
Mainly used for assembling "Airfix" and similar plastic models, but also for paper.<br />
<br />
===Silicone Glue===<br />
Silicone filler is most commonly used for sealing around bathroom and kitchen fittings, and around window frames, but can also be used as an adhesive. It remains flexible after it has set but is not especially strong, and surfaces need to be clean and dry. You may see its use in consumer electronics where a blob has been applied to retain a flying lead in position.<br />
<br />
[https://sugru.com/ Sugru] is a type of silicone, with hundreds of uses in fixing and crafts. It comes as a mouldable putty rather than a liquid and sets into silicone rubber. Perhaps the commonest use case in fixing is as strain relief on a headphone cable where the cable enters the jack plug - a point where the cable frequently frays and breaks.<br />
<br />
A part used sachet of Sugru cannot be effectively resealed to keep it fresh, and once opened, a tube of silicone adhesive is difficult to effectively seal. After a few months you may find the nozzle if not the whole tube has set solid.<br />
<br />
===Flour and water paste===<br />
Mix a little flour with water to make a moist spreadable paste. This makes a surprisingly good glue for paper, card and fabric if you have nothing else to hand, and is child-safe.<br />
<br />
==Sticky Tapes==<br />
<br />
===PVC Tape===<br />
PVC insulating tape is good for wrapping around exposed wires and electrical connections, however, it should never be use as the sole protection in the case of mains (or higher) voltages. If two wires are simply twisted together, heat may be generated when a current flows and this could melt the tape. (Use solder or a crimped or screw-secured connection - see [[Connecting and joining wires]].)<br />
<br />
PVC tape sticks reasonably well but it's stretchy and not especially strong, so shouldn't be used simply for fixing.<br />
<br />
===Gaffer Tape and Duct Tape===<br />
These are very strong tapes used for holding things together. Gaffer tape has a fabric backing and is designed to be removable; it is often used to tape cables down to avoid trip hazards or to conceal them on stage. Duct tape has a plastic-coated fabric back and is designed to stick permanently: it is used for all sorts of repairs and is waterproof and very durable. The two are similar, are often confused and are interchangeable for many uses.<br />
<br />
These tapes are very versatile. It's said that Mission Control knew they had a chance of saving the Apollo 13 crew when they realised they had duct tape on board.<br />
<br />
===Self-amalgamating Tape===<br />
This isn't strictly adhesive, but when wrapped around an electrical junction or low pressure water pipe the layers fuse together seamlessly.<br />
<br />
===Sellotape and Scotch Tape===<br />
These should only be used for paper and parcels.<br />
<br />
==Conductive Sticky Stuff==<br />
<br />
===Bare Conductive electric paint===<br />
[http://www.bareconductive.com/ Bare Conductive] is an electrically conductive paint which you may be able to use to bridge a broken connection. It has a much higher resistance than copper or solder and so isn't suitable where a low resistance connection is required or where it must carry more than a few mA. It should be fine, however, for connections to an LCD, or to the momentary-contact push buttons on nearly all modern electronic equipment.<br />
<br />
A slight problem with it is that once opened, the dispenser dries out over a period of months. You may be able to rejuvenate it if you can unblock the nozzle and introduce a little plain water, then shake vigorously. A hypodermic syringe would be ideal for this.<br />
<br />
===Conductive Silver Paint===<br />
If you need a low resistance join for example to mend a broken circuit board trace then conductive silver paint may well do the job, although it's expensive. Like bare Conductive, once opened it dries out quite quickly, and being solvent based can't so easily be restored.<br />
<br />
==Other Sticky Stuff==<br />
<br />
===Sugru===<br />
Sugru comes in sachets and initially has a putty-like consistency but cures to a synthetic rubber. Excellent for adding protection and strain relief to a low voltage cable (such as a headphone lead) where the outer insulation is starting to crack on its entry to the plug. The website [http://www.sugru.com www.sugru.com] gives hundreds of other examples of its use. It comes in black or white and several bright colours.<br />
<br />
A drawback is that part used sachets can't be resealed and will very quickly go off, and unused sachets have a limited shelf life. This can be extended somewhat by keeping them in the fridge.<br />
<br />
===Thermoplastics===<br />
Polymorph consists of granules which turn soft when heated to 62 degrees centigrade, then harden again when they cool. The Register [http://m.theregister.co.uk/2011/12/31/christmas_repairs/ described] it as 'the stuff of the gods, or would be if it had been around when the gods were choosing a construction material.'<br />
<br />
Formcard is essentially the same except that it comes in convenient credit card sized pieces. The idea is that you can easily keep one with you for use whenever you might need it. It can be softened in hot water as required and then can be moulded for a variety of uses before it sets hard on cooling. It was launched in a [https://www.kickstarter.com/projects/formcard/formcard-melt-mould-make-mend Kickstarter] campaign in late 2015 and is now available from [http://www.formcard.com/ the inventors website].<br />
<br />
===Modelling Clay===<br />
There are several types of modelling clay, mostly used for making rather than repairing. Polymer clay can be cured by heating to a modest temperature of 130⁰C for 15 minutes and doesn't shrink or change shape in the process. It can be obtained from hobby, craft and art stores.<br />
<br />
===Milliput===<br />
[http://www.milliput.com Milliput] is a two-part, cold setting, non-shrinking epoxy putty which can be used for repairs on many types of materials including metals, plastics, masonry, wood, glass and ceramics.<br />
<br />
==How to remove glue==<br />
Sometimes your problem might actually be to unglue something, either because it wasn't glued properly or because you need to disassemble the item for repair. Different glues will respond to different solvents, but two of the best for difficult cases are:<br />
*Acetone (or nail polish remover)<br />
*Proprietary glue removers (search online) especially those advertised for removing super glue.<br />
<br />
The latter often contain heterocyclic ketone, which is a powerful glue remover. (Acetone is a ketone, but not a heterocyclic one.)<br />
<br />
Be aware that any solvents may irritate sensitive skin or discolour the glued item, especially fabrics.<br />
<br />
==External links==<br />
* [https://therestartproject.org/podcast/materials-hack-fix Our Restart Radio show "Materials we use to hack and fix"]<br />
<br />
[[Category:Skills]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Sticky_Stuff&diff=3528Sticky Stuff2020-05-21T08:59:41Z<p>Pleriche: /* Types of Glue */ Added silicone and flour-and-water.</p>
<hr />
<div>There are many different type of adhesives, glues and sticky tapes, each with its own strengths and weaknesses. Here you can learn which would be best for particular repair.<br />
<br />
==Summary==<br />
When things fall part there are various types of glue and sticky tape that you can use to stick them back together again, but different ones are good for different things. This page will help you choose the right one.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Broken mains electrical items repaired with adhesive and/or sticky tape will necessarily fail the visual inspection part of a PAT electrical safety test. If you decide on such a repair (at your own risk) you should at least ensure that any glue is supported by strong tape such as gaffer tape wrapped completely around the item, with a good overlap.<br />
::Some types may cause skin irritation or give off unhealthy fumes.<br />
<br />
==Types of Glue==<br />
There are lots of different types of glue. The first few below are the most useful in a Restart situation but others may come in handy for general repairs or for making stuff.<br />
<br />
Always read the instructions or you may not get satisfactory results, and might be unaware of any potential hazards.<br />
<br />
===Superglue===<br />
[[File:Warning03.png|30px|left]]<br />
::Superglue will stick your fingers together instantly. You may find it rather embarrassing to have to go to A&E to get them unstuck.<br />
<br />
Superglue will make a very strong join provided the surfaces to be mated fit together very closely, but it's not so good at filling gaps. Buy it in small tubes, try to clear the nozzle after use, and make sure you put the lid on tight as otherwise it will set solid.<br />
<br />
If you do need to fill a gap then you can use the superglue and baking powder trick. Place a little baking powder in the gap - only as much as you can soak with one drop of superglue, then add the drop of superglue. You can repeat the process as often as needed to fill a larger gap. It will set in a very few minutes into a very hard and tough solid.<br />
<br />
===Epoxy===<br />
Epoxy glue comes in 2 separate tubes. Squeeze the same amount from each tube and mix well. Be sure to put the right lid back on the right tube, or you'll never get them off again!<br />
<br />
Epoxy glue is very strong and sticks to most things. Although it's best if the mating surfaces fit well together, you can use it to fill gaps or you can build it up around a join to add strength.<br />
<br />
Rapid epoxy sets in a few minutes and so is very useful, though it takes longer to achieve full strength.<br />
<br />
===Hot Melt===<br />
Hot melt glue comes in sticks which you have to feed into a glue gun. Cheap glue guns are available for just a few pounds. Apply the glue and join the parts together immediately. The glue will set in a few seconds as it cools but will take a little longer to gain full strength.<br />
<br />
Hot melt glue remains flexible after it has set and so is good for repairing flexible things, like sticking the sole back on a shoe. Where a wire is soldered to a circuit board a blob of hot melt glue is very good for preventing the wire from flexing and breaking at the solder joint.<br />
<br />
===PVA Glue===<br />
This works well with porous materials such as paper, wood and cloth. You may have first met it at a tender age as school glue. It's used in handicrafts, bookbinding, woodworking and as wallpaper adhesive. A screwed and glued joint in woodworking is very strong.<br />
<br />
===Vinyl Adhesive===<br />
This is good for sticking PVC as it consists of PVC dissolved in a solvent. This partially dissolves the surfaces to be joined, formng a weld as it sets.<br />
<br />
===Glass Bond===<br />
This is a UV-cured adhesive which is good for sticking glass, transparent acrylic or metal to glass or acrylic. To cure it you can use a UV torch or bank note checker, available cheaply on eBay. Alternatively you can simply leave it in sunlight, though it will take considerably longer.<br />
<br />
===Polystyrene Glue===<br />
Mainly used for assembling "Airfix" and similar plastic models, but also for paper.<br />
<br />
===Silicone Glue===<br />
Silicone filler is most commonly used for sealing around bathroom and kitchen fittings, and around window frames, but can also be used as an adhesive. It remains flexible after it has set but is not especially strong, and surfaces need to be clean and dry. You may see its use in consumer electronics where a blob has been applied to retain a flying lead in position.<br />
<br />
[https://sugru.com/ Sugru] is a type of silicone, with hundreds of uses in fixing and crafts. It comes as a mouldable putty rather than a liquid and sets into silicone rubber. Perhaps the commonest use case in fixing is as strain relief on a headphone cable where the cable enters the jack plug - a point where the cable frequently frays and breaks.<br />
<br />
A part used sachet of Sugru cannot be effectively resealed to keep it fresh, and once opened, a tube of silicone adhesive is difficult to effectively seal. After a few months you may find the nozzle if not the whole tube has set solid.<br />
<br />
===Flour and water paste===<br />
Mix a little flour with water to make a moist spreadable paste. This makes a surprisingly good glue for paper, card and fabric if you have nothing else to hand, and is child-safe.<br />
<br />
==Sticky Tapes==<br />
<br />
===PVC Tape===<br />
PVC insulating tape is good for wrapping around exposed wires and electrical connections, however, it should never be use as the sole protection in the case of mains (or higher) voltages. If two wires are simply twisted together, heat may be generated when a current flows and this could melt the tape. (Use solder or a crimped or screw-secured connection - see [[Connecting and joining wires]].)<br />
<br />
PVC tape sticks reasonably well but it's stretchy and not especially strong, so shouldn't be used simply for fixing.<br />
<br />
===Gaffer Tape and Duct Tape===<br />
These are very strong tapes used for holding things together. Gaffer tape has a fabric backing and is designed to be removable; it is often used to tape cables down to avoid trip hazards or to conceal them on stage. Duct tape has a plastic-coated fabric back and is designed to stick permanently: it is used for all sorts of repairs and is waterproof and very durable. The two are similar, are often confused and are interchangeable for many uses.<br />
<br />
These tapes are very versatile. It's said that Mission Control knew they had a chance of saving the Apollo 13 crew when they realised they had duct tape on board.<br />
<br />
===Self-amalgamating Tape===<br />
This isn't strictly adhesive, but when wrapped around an electrical junction or low pressure water pipe the layers fuse together seamlessly.<br />
<br />
===Sellotape and Scotch Tape===<br />
These should only be used for paper and parcels.<br />
<br />
==Conductive Sticky Stuff==<br />
<br />
===Bare Conductive electric paint===<br />
[http://www.bareconductive.com/ Bare Conductive] is an electrically conductive paint which you may be able to use to bridge a broken connection. It has a much higher resistance than copper or solder and so isn't suitable where a low resistance connection is required or where it must carry more than a few mA. It should be fine, however, for connections to an LCD, or to the momentary-contact push buttons on nearly all modern electronic equipment.<br />
<br />
A slight problem with it is that once opened, the dispenser dries out over a period of months. You may be able to rejuvenate it if you can unblock the nozzle and introduce a little plain water, then shake vigorously. A hypodermic syringe would be ideal for this.<br />
<br />
===Conductive Silver Paint===<br />
If you need a low resistance join for example to mend a broken circuit board trace then conductive silver paint may well do the job, although it's expensive. Like bare Conductive, once opened it dries out quite quickly, and being solvent based can't so easily be restored.<br />
<br />
==Other Sticky Stuff==<br />
<br />
===Sugru===<br />
Sugru comes in sachets and initially has a putty-like consistency but cures to a synthetic rubber. Excellent for adding protection and strain relief to a low voltage cable (such as a headphone lead) where the outer insulation is starting to crack on its entry to the plug. The website [http://www.sugru.com www.sugru.com] gives hundreds of other examples of its use. It comes in black or white and several bright colours.<br />
<br />
A drawback is that part used sachets can't be resealed and will very quickly go off, and unused sachets have a limited shelf life. This can be extended somewhat by keeping them in the fridge.<br />
<br />
===Thermoplastics===<br />
Polymorph consists of granules which turn soft when heated to 62 degrees centigrade, then harden again when they cool. The Register [http://m.theregister.co.uk/2011/12/31/christmas_repairs/ described] it as 'the stuff of the gods, or would be if it had been around when the gods were choosing a construction material.'<br />
<br />
Formcard is essentially the same except that it comes in convenient credit card sized pieces. The idea is that you can easily keep one with you for use whenever you might need it. It can be softened in hot water as required and then can be moulded for a variety of uses before it sets hard on cooling. It was launched in a [https://www.kickstarter.com/projects/formcard/formcard-melt-mould-make-mend Kickstarter] campaign in late 2015 and is now available from [http://www.formcard.com/ the inventors website].<br />
<br />
===Modelling Clay===<br />
There are several types of modelling clay, mostly used for making rather than repairing. Polymer clay can be cured by heating to a modest temperature of 130⁰C for 15 minutes and doesn't shrink or change shape in the process. It can be obtained from hobby, craft and art stores.<br />
<br />
===Milliput===<br />
[http://www.milliput.com Milliput] is a two-part, cold setting, non-shrinking epoxy putty which can be used for repairs on many types of materials including metals, plastics, masonry, wood, glass and ceramics.<br />
<br />
==How to remove glue==<br />
Sometimes your problem might actually be to unglue something, either because it wasn't glued properly or because you need to disassemble the item for repair. Different glues will respond to different solvents, but two of the best for difficult cases are:<br />
*Acetone (or nail polish remover)<br />
*Proprietary glue removers (search online) especially those advertised for removing super glue.<br />
<br />
The latter often contain heterocyclic ketone, which is a powerful glue remover. (Acetone is a ketone, but not a heterocyclic one.)<br />
<br />
Be aware that any solvents may irritate sensitive skin or discolour the glued item, especially fabrics.<br />
<br />
==External links==<br />
* [https://therestartproject.org/podcast/materials-hack-fix Our Restart Radio show "Materials we use to hack and fix"]<br />
<br />
[[Category:Skills]]</div>Plerichehttps://wiki.restarters.net/index.php?title=How_radios_work&diff=3526How radios work2020-05-18T09:48:59Z<p>Pleriche: /* Frequency vs wavelength */</p>
<hr />
<div>This page covers radios, the several different types, and their principles of operation, to enable you to go a little deeper than visual fault finding.<br />
<br />
==Summary==<br />
Often, radios can be fixed simply by looking for the sort of problems common to all electronic gadgets, with very little idea of how they actually work. But when that approach fails, it's necessary to have a basic grounding in the theory of operation in order to go deeper. This page aims to provide that grounding, describing the several types and their principles of operation.<br />
<br />
We start by looking at the basic theory of radio transmission, then go on to examine how that theory is put into practice in several different types of radio.<br />
<br />
A separate page on [[Portable radios]] covers the practical aspects of diagnosing and fixing radios.<br />
<br />
==Basic radio theory==<br />
In theory, you might be able to connect a microphone, through a powerful amplifier, directly to a transmitting aerial. In practice that wouldn't work because (for reasons we'll come to) you'd need an aerial many miles long, and there'd be no way to transmit more than one programme at a time without them getting mixed up.<br />
<br />
An Audio Frequency (AF) signal, such as comes out of a microphone or could be fed into a loudspeaker, consists of frequencies in the range 20Hz - 20kHz (20 - 20,000 vibrations per second). In order to transmit it, that signal has to be impressed in some way upon a much higher Radio Frequency (RF) "carrier". There are several ways of doing that, the process being known as "modulation". A radio receiver essentially has three jobs to do: selection of the station you want to listen to and rejection of all the others ("tuning"), recovering the audio signal from modulated RF ("demodulation"), and amplification of the weak signal from the aerial in order to drive a loudspeaker or headphones. Tuning obviously has to be done before demodulation, but amplification is often performed before, between and after the other two functions.<br />
<br />
We'll start by looking at several methods of modulation, then explain how tuning is achieved.<br />
<br />
===Amplitude Modulation (AM)===<br />
[[File:AM.png|200px|thumb|left|Amplitude modulation.]] The simplest form of modulation is Amplitude Modulation, or AM. As shown in the diagram, the audio (AF) signal is impressed on the RF carrier as changes in amplitude.<br />
<br />
Demodulation is simple. If you were to feed the modulated RF directly into a loudspeaker, you would hear nothing as it's positive just as much as it's negative and oscillates between the two far too fast for a loudspeaker or headphones to respond to. But if you chop off all the negative bits and average out the positive bits that are left, the result will follow the original AF signal which the speaker can then reproduce.<br />
<br />
A disadvantage of AM is that it's susceptible to interference from things like a sparking electric motor, a car's ignition system or the fridge turning on and off. These all generate spikes of amplitude which the loudspeaker reproduces as clicks.<br />
<br />
===Frequency Modulation (FM)===<br />
[[File:FM.png|200px|thumb|right|Frequency modulation.]] In Frequency modulation or FM, the amplitude of the carrier remains the same but the frequency is varied in sympathy with the audio signal, as shown in the second diagram. There are several methods of demodulation and these are generally slightly more complicated than for AM but fortunately we don't need to go into them for the purposes of repair.<br />
<br />
An advantage of FM is that any spikes in the signal from interference can simply be chopped off by limiting the amplitude to a maximum value, with the result that they will hardly be heard in the audio output.<br />
<br />
===Digital Modulation===<br />
In digital radio (DAB, or Digital Audio Broadcasting) the audio signal is first converted to digital: the amplitude of the signal (or each channel in the case of stereo) is sampled, measured and converted to a binary number many times per second. The absolute minimum rate or sampling is twice for every cycle of audio, so for sound containing frequencies up to 20kHz the minimum "sampling rate" as it's called is 40,000 samples per second.<br />
<br />
This produces rather a lot of data, but since each sound wave typically only differs slightly from the previous one there is much scope for data compression. This is done by a codec (coder-decoder).<br />
<br />
Error correction bits are added to the compressed output of the codec allowing short sequences of corrupted bits to be corrected at the receiving end, and longer sequences to be detected. The resultant data streams from a number of different programmes are then multiplexed together creating an "ensemble" which is used to modulate a carrier.<br />
<br />
A digital receiver simply performs all these processes in reverse.<br />
<br />
DAB+ is a newer variant which uses a more efficient codec and more powerful error correction, allowing more programmes to be broadcast in a single ensemble. Whilst it allows successful reception of a weaker signal, there is a sharper "cliff edge" where a weak signal degenerates into a burbling noise before being lost.<br />
<br />
==Types of Radio==<br />
<br />
===Tuned Radio Frequency (TRF)===<br />
[[File:Crystal-set.png|200px|thumb|right|A crystal set radio.]]A crystal set is the simplest practical type of radio, and demonstrates some of the basic principles, except that it provides no amplification, relying entirely on the energy delivered by the aerial. The diagram shows a very simple crystal set.<br />
<br />
The signal picked up by the aerial is passed to the coil or inductor L1 and the tuning capacitor C1, which form a "tuned circuit". The capacitor stores electrical energy much like a spring stores mechanical energy, and the inductor provides a kind of momentum to a flow of current like the momentum of a heavy object in motion. Just like a weight suspended by a spring, or a pendulum, or a guitar string, the inductor and capacitor have a particular resonant frequency, and tend to reinforce any signal of that frequency coming from the aerial, at the expense of other frequencies. (The arrow through the C1 symbol indicates that it's a variable capacitor, adjustable by a dial on the front panel.)<br />
<br />
The diode D1 performs the demodulation, passing current in one direction only. The RF fluctuations are smoothed out by the capacitor C2 leaving us with the original audio signal which is fed to the headphones SPK1.<br />
<br />
[http://www.crystalradio.net/crystalplans/xximages/boys_book_of_crystal_sets.pdf The Boy's Book of Crystal Sets] is from another age but gives a more detailed yet very simple explanation of a crystal set, well worth looking at, whatever your age or gender!<br />
<br />
Apart from poor sensitivity due to the lack of amplification, a crystal set also has poor selectivity, meaning that nearby stations are not well discriminated and a strong station still to be heard while trying to tune in to a nearby weak station. There are two reasons for this: firstly, there is only a single tuned circuit, and secondly, energy is drawn from that tuned circuit to drive the headphones, which causes its resonant frequency to be less well defined.<br />
<br />
Amplification can be added either to the RF signal before demodulation, or to the AF signal afterwards, or more usually both. If stages of amplification are added before, then additional tuned circuits can be added before, between and after the stages to improve selectivity. A difficulty arises, though, in that all the tuned circuits must track one another closely as you turn the tuning knob, making it increasingly difficult to design a radio with more than 2 or 3 separate tuned circuits.<br />
<br />
===Superhet===<br />
[[File:beats.png|200px|thumb|right|Two different frequencies creating beats.]]<br />
The vast majority of AM and FM radios follow the superhet design, which overcomes the problem of needing to make multiple tuned circuits track one another.<br />
<br />
If two different frequencies are combined, sometimes they will be in step and reinforce each other and at other times they will be out of step and cancel, as shown in the diagram. So if for example two musical instruments are playing together, one at 440Hz and the other at 441Hz, once per second they will be in phase, and in between they will gradually go out of phase before coming back in phase again, like two people walking side by side with one taking slightly longer paces than the other. So you will hear the two notes "beating" against one another with a beat frequency of 1Hz, which is the difference between the two frequencies.<br />
<br />
The effect is also known as a heterodyne. A superhet receiver (it should really be called an ultrahet, but never is) relies on creating an ultrasonic heterodyne between the incoming RF signal and another signal of different frequency generated within the receiver.<br />
<br />
[[File:Superhet.png|400px|thumb|right|Block diagram of a superhet receiver.]]<br />
A local oscillator produces a signal which can be tuned to a frequency which differs from the frequency of the station you want to receive by typically (for AM) 455kHz. A "mixer" combines this with the desired signal to produce a beat frequency of 455kHz. This can then be amplified and tuned by as many tuned circuits as the designer wants, each tuned to a fixed frequency of 455kHz. As a result any station can be tuned by converting its frequency in this way to 455kHz, known as the Intermediate Frequency or IF, since it comes between the RF and the AF. Neat!<br />
<br />
In the case of an FM receiver the RF is much higher frequency so an IF of 10.7MHz is normally used. An AM/FM receiver has both 455KHz and 10.7KHz tuned circuits in its IF stages, allowing it to work equally well for both bands.<br />
<br />
In fact, if you mix two frequencies f1 and f2, you get not only f1 - f2 but also f1 + f2. This means that there would be a second frequency that would be converted to the same IF frequency and possibly cause interference. To avoid this there is normally a single tuned circuit and stage of amplification to filter out any such "ghost" stations before the mixer. This tuned circuit has to track the local oscillator frequency, but that's still easier than tracking several more tuned circuits as a TRF radio would have to.<br />
<br />
In a reasonably modern receiver with push-button tuning (such as a car radio), a digital circuit replaces the local oscillator. This generates a precise frequency derived digitally from an accurate quartz crystal oscillator.<br />
<br />
The diagram above gives a functional description of a typical superhet receiver:<br />
* The aerial feeds into a tuned circuit and often a single stage of amplification.<br />
* The mixer combines the signal with the output of a local oscillator to generate the IF.<br />
* The IF stages consist of one of more stages of amplification and with further tuned circuits.<br />
* A demodulator (AM or FM or both) recovers the AF.<br />
* A power amplifier further amplifies the signal in order to drive a loudspeaker.<br />
<br />
===Digital===<br />
[[File:DAB_Radio.png|200px|thumb|right|DAB Radio Block Diagram.]]<br />
The diagram shows the essentials of a DAB radio. The intricacies of the DAB tuner and decoder are normally hidden within one or more integrated circuits protected by a metal screen. The RF goes in one end and the AF comes out of the other and everything in between is hidden. An audio amplifier driving the loudspeaker is generally distinguishable as a separate module. A microcontroller detects depressions of the push-buttons, drives the LCD display, and sends digital tuning controls to the DAB module. The [[Power supplies|power supply]] takes the battery or mains power and delivers a precise voltage (typically 3.3V or 5V) needed by the digital circuits as well as usually a higher voltage for the audio amplifier.<br />
<br />
====Software Defined Radio (SDR)====<br />
[[File:DAB+FM+DVB-T.jpg|200px|thumb|right|A digital TV USB dongle which, plugged into a computer, comprises a Software Defined Radio.]]<br />
The digital revolution has resulted in many functions in everything from cars to washing machines and toasters, previously performed by single purpose mechanical or electrical designs, to be taken over by [[Glossary:Software|software]]. Radios are no exception.<br />
<br />
In a Software Defined Radio or SDR, the signal from the aerial is converted to digital form by a Digital to Analogue Converter (DAC) and the resultant stream of data is processed by software to perform the functions of tuning and demodulation. Using this approach, a radio can be made to receive AM, FM, DAB radio, digital or satellite TV, Morse code even, or any of a multitude of different digital formats such as WiFi, Bluetooth, GPS all just by changing the software.<br />
<br />
Despite the extraordinary power of modern processors it's still not normally practicable to connect the aerial direct to the DAC. For a start, the signal would be far too weak. Also, the cost of a DAC rises sharply as you seek faster sampling rates so directly digitising a signal in the [[Glossary:GHz|GHz]] range would be infeasable at reasonable cost.<br />
<br />
For these reasons some analogue circuitry is retained. This not only amplifies the signal but also converts it to a more manageable range of frequencies using the [[#Superhet|superhet]] principle described earlier. So if you have a DAC with a maximum sample rate of 50 million samples per second (hence capable of directly digitising frequencies up to 25MHz) you can make an SDR which can receive signals within any 25MHz band determined by your local oscillator frequency. This can be chosen or tuned over an unlimited range of freqencies.<br />
<br />
The USB TV dongles available very cheaply contain a pre-amplifier, local oscillator, mixer and DAC. Plugged into a computer loaded with suitable software, this comprises an SDR. Indeed, alternative software is available making it possible to experiment with your own SDR and receive signals of various types over a wide range of frequencies as described in [https://www.instructables.com/id/A-Software-Defined-Radio-on-a-Shoestring/ this Instructable].<br />
<br />
Perhaps the most dramatic and impressive recent example of an SDR is the [https://eventhorizontelescope.org/ Event Horizon Telescope]. This imaged the super-massive black hole at the centre of galaxy M87 by combining and processing the digitised outputs of 10 radio telescopes across the globe using highly sophisticated software.<br />
<br />
==Frequency, Wavelength, Wavebands and Aerials==<br />
<br />
===Frequency vs wavelength===<br />
Sometimes the frequency of a radio station is given, other times its wavelength. There is a simple relationship between the two.<br />
<br />
Radio waves (and light) travel at 300 million metres per second. So if you were to count 300 million radio waves passing you per second (i.e. they have a frequency of 300MHz) then each peak must be racing past you just a metre behind the previous one. This is the wavelength - the distance between successive peaks (or troughs).<br />
<br />
So if you multiply the distance between each wave and the next (the wavelength) by the number of them passing you per second (the frequency) we get the speed of light (or radio waves). Alternatively you can divide the speed of light by the frequency to get the wavelength, or by the wavelength to get the frequency.<br />
<br />
In short:<br />
* Divide 300 by the frequency in MHz to get the wavelength in metres, or<br />
* Divide 300 by the wavelength in metres to get the frequency in MHz.<br />
<br />
===Wavebands===<br />
The frequency spectrum is by convention divided into the following bands:<br />
* Long Wave (LW) 150 - 285kHz (2000 - 1053m)<br />
* Medium Wave (MW) 525 - 1605kHz (570 - 187m)<br />
* Short Wave (SW)1.8 - 30MHz (167 - 10m)<br />
* VHF 40 - 300MHz (7.5 - 1m)<br />
* UHF 300MHz - 3GHz (1m - 10cm)<br />
<br />
AM radio occupies the Long and Medium wavebands.<br />
<br />
FM radio is transmitted in the VHF band in the range 88 - 108MHz.<br />
<br />
DAB radio is also transmitted in the VHF in the range 175 - 240MHz.<br />
<br />
Long waves are getting towards being comparable in length to the curvature of the earth, and so to an extent they can bend over the horizon. As a result they can be received at distances of many hundreds of miles. Much shorter wavelengths allow little more than line-of-sight communication.<br />
<br />
In between, Short Waves don't bend well over the horizon yet can be received over distances of thousands of miles. This is because they can be reflected back and forth between the earth and the ionosphere (an ionised and electrically conductive layer of the atmosphere at altitudes of tens to hundreds of miles).<br />
<br />
===Aerials===<br />
A radio aerial works best if its length is half the wavelength of the stations it needs to receive. This is quite impracticable for Long and Medium wavebands but moving towards the upper VHF and into the UHF bands it becomes quite a manageable length. The multiple element TV aerials on roofs and chimneys consist of half-wavelength rods.<br />
<br />
In the early days of radio, an aim was to put up the longest possible aerial in order to get good LW and MW reception. Since the days of portable transistor radios a ferrite rod aerial has invariably been used for these bands.<br />
<br />
This consists of a magnetic but non-conductive rod of a ceramic material (ferrite) typically with two coils of wire around it, one for Medium Waves and the other for Long Waves. The ferrite rod has the effect of concentrating the magnetic component of the radio waves causing it to induce a signal in the coils. (Radio waves consist of interlinked waves in the electric and magnetic fields.) It has to be non-conducting as otherwise the radio waves would induce a current in the rod itself rather than in the coils around it. The ferrite rod aerial is very obvious if you open any AM radio.<br />
<br />
[[Category:Theory]]</div>Plerichehttps://wiki.restarters.net/index.php?title=Electric_motors&diff=3525Electric motors2020-05-16T11:16:06Z<p>Pleriche: /* Induction Motors */</p>
<hr />
<div>This pages covers electric motors of various types, how to identify them and understand their common failure modes, and how to test them.<br />
<br />
==Summary==<br />
Many devices and appliances contain electric motors. This page will help you understand how they work, what can go wrong, and maybe how to fix them.<br />
<br />
===Safety===<br />
[[File:Warning03.png|30px|left]]<br />
::Motors in domestic appliances can be quite powerful, and along with associated gears and mechanisms, can cause injury. As with all mains electrical appliances, it is essential to unplug them before starting work. The appliance should be [[PAT testing|PAT tested]] both before and after any disassembly or repair is attempted.<br />
<br />
==Types of Motor==<br />
<br />
There are many types of electric motor but nearly all fall into three main types. They all have two main components:<br />
* The Rotor - the bit that spins, and<br />
* The Stator - the bit that doesn't spin.<br />
They all rely on '''electromagnetism'''. When an electric current flows through a coil of wire it creates a magnetic field. The coil is usually wound around an iron core which then gets magnetised, greatly increasing the magnetism.<br />
<br />
===DC and Universal (AC/DC) Motors===<br />
[[File:Img_1924a.jpg|180px|thumb|left|A universal motor, dismantled.]]<br />
[[File:Img_1926a.jpg|180px|thumb|right|A universal motor showing the rotor with the commutator.]]<br />
[[File:Img_1928a.jpg|180px|thumb|right|A universal motor showing the stator with the brushes at the far end.]]<br />
The stator is a permanent magnet or an electromagnet.<br />
<br />
In the simplest toy motors, the rotor is another coil, or a whole series of coils in all practical motors, wound around a laminated iron core.<br />
<br />
A pair of carbon '''brushes''' supply current to the rotor via a '''commutator''', which continually switches the current in the rotor into whichever coils are at right angles to the stator coil at any given moment. This produces a continuous turning force.<br />
<br />
In an '''electronically commutated''' or '''brushless''' motor, the rotor is often a permanent magnet. Electronic circuits sense the rotor position and continually switch the current in a series of stator coils in order to turn the rotor. This avoids the need for any electrical connection to the rotor and so increases the reliability.<br />
<br />
[[Glossary:DC|DC]] and universal motors work equally well as dynamos, and generate a [[Glossary:Volt|voltage]] which opposes the applied voltage. This is known as a "back emf (electro-motive force)". Under a light load, these motors speed up until they are generating nearly as much voltage as is applied. Consequently, it's easy to vary the speed just by varying the applied voltage.<br />
<br />
The commutator and brushes (except in electrically commutated motors) are subject to wear and can produce sparks. Such motors are therefore not used where the highest reliability is required or where there is a risk of fire or explosion from flammable gasses.<br />
<br />
The dynamo effect is at a minimum when the motor first starts and before it reaches full speed. This allows the motor to draw a heavy current and generate a very large starting torque (i.e. turning force). This is particularly useful in electric vehicles and trains where a powerful force is needed to initially set them in motion.<br />
<br />
[[File:Coreless_motor1.jpg|180px|thumb|right|A coreless motor - rotor and shell with permanent magnet visible inside the shell.]]<br />
In a '''coreless motor''' the rotor windings are formed into a resin bonded hollow cylinder - there is no iron core. This rotates around a static permanent magnet located within it. The magnetic field passes from one pole of the magnet through the rotor windings and then returns through the steel motor case, once again through the opposite side of the rotor and hence back to the other pole of the magnet.<br />
[[File:Coreless_motor2.jpg|180px|thumb|left|A coreless motor - Commutator and brushes.]]<br />
The current is fed to the rotor through brushes and a commutator just as in any other DC or universal motor. The absence of an iron core improves efficiency, saves weight and reduces inertia, allowing very rapid accelleration and decelleration.<br />
<br />
Coreless motors are often found in small quadrocopters and other toys as well in medical equipment, robotics and whenever a small highly efficient and responsive motor is required.<br />
<br />
Most hand power tools use universal motors. Computer fans, hard disk motors and larger quadrocopter and remote control models generally use electronically commutated motors.<br />
<br />
There is an excellent [http://woodgears.ca/motors/dc.html article] with an included video describing and demonstrating how a DC motor works.<br />
<br />
===Induction Motors===<br />
These are simpler in construction but not quite so easy to understand.<br />
<br />
If you move a magnet across a piece of metal, the moving magnetic field generates a circulating electric current in the metal. This current, in turn, creates a magnetic field which interacts with the applied field in such a way as to create a drag, opposing the motion.<br />
<br />
[[File:Img_1887a.jpg|180px|thumb|right|A small shaded pole induction motor, dismantled.]]<br />
The stator consists of two or more coils arranged to create a rotating magnetic field. The rotor contains a number of thick copper loops to maximise the drag created by the rotating magnetic field. The rotor speeds up until it's spinning nearly as fast as the rotating magnetic field.<br />
<br />
Induction motors only work on an [[Glossary:AC|AC]] supply (which reverses in direction 100 times per second), as this is how the stator can produce a rotating magnetic field.<br />
<br />
Since the frequency of the AC supply is fixed, you can't easily vary the speed of an induction motor. However, with 4 or 6 (or more) stator coils instead of 2, and by switching the way the AC supply is fed to them, it's possible to arrange for the rotating magnetic field to rotate at half, third (or some other fractional) speed.<br />
<br />
In most induction motors the stator produces more of an up and down than a true rotating magnetic field, but with a bit of a twist one way on the way up and the other on the way down. This means that the starting torque is low. Hence they are normally used where this doesn't matter, e.g. in a fan, which encounters little air resistance until it reaches full speed.<br />
<br />
[[File:Induction motor with starter winding.jpg|180px|thumb|left|An induction motor with starter winding.]]<br />
There are several ways in which the twist is obtained. In a shaded pole motor a thick loop of copper is wound around a portion of each pole (as can be seen in the first photo). This causes the magnetisation of that portion of the pole to be delayed slightly by the build up of current in the loop, so giving the required twist. The copper loop wastes power so this method is only used in small motors such as are very commonly found in desk fans.<br />
<br />
Larger motors have a second stator winding offset from the main one, which is fed with an out of phase current. A [[Basic_electronic_components#Capacitors|capacitor]] (a large cylindrical component which can't be missed) or sometimes a resistor provides the phase shift. The picture shows an example from a rotary lawn mower motor, with the 90 degree offset second winding clearly visible.<br />
<br />
(An interesting feature of the motor shown is that it had a braking mechanism to stop the blade rotating once the power was turned off. A metal disk is visible on the spindle with a spring underneath which pressed it against the three brake pads visible around the bearing. When power is applied, the magnetic field pulls this disk down and away from the brake pads. Corosion of the disk caused the braking action to become excessively fierce. The flats on the spindle then wore away the coresponding flats on a plastic impellor to which the blade was attached. The angular momentum of the blade then caused its retaining bolt to work loose.)<br />
<br />
The second stator winding may waste energy once the motor has started and hence may be switched out by a centrifugal switch. Alternatively there may be a thermistor which quickly heats up with the current flow and as it does so, its resistance increases so reducing the current in the second stator winding.<br />
<br />
Large industrial multi-horsepower induction motors are often fed from a 3-phase supply. With 3 windings (or a multiple of 3) fed from the 3 phases, these naturally create a rotating magnetic field and so are self-starting.<br />
<br />
There is an excellent [http://woodgears.ca/motors/ac.html article] with included video describing and explaining how induction motors work.<br />
<br />
===Synchronous Motors===<br />
<br />
These are similar to induction motors, in that the stator creates a rotating magnetic field. The difference is that the rotor is a permanent magnet and hence is forced to rotate at the same speed as the magnetic field instead of lagging in speed as in an induction motor.<br />
<br />
Imagine two tin cans, one inside the other. If you fill the space in between with treacle and rotate the outer can, it will drag the inner one around with it even if you resist its motion. The difference in speed will depend on the resistance you apply. That's like an induction motor. If instead of treacle, you attach the inner can to the outer one with springs, the inner will be forced to rotate at the same speed, but will stretch the springs and lag in position, though not in speed, as you increase the resistance. This is like a synchronous motor.<br />
<br />
Small synchronous motors are used in electro-mechanical timers and clocks where their rotation is locked to the [[Glossary:Frequency|frequency]] of the [[Glossary:AC|AC]] mains. Large industrial plant also sometimes uses very much bigger and more powerful synchronous motors. A car alternator and the generators in a power station are synchronous motors being used as generators.<br />
<br />
Since a synchronous motor doesn't work properly until the rotor gets up to speed, some cunning means must be applied to get it started. In small clock and timer motors this is usually achieved by the way the iron of the stator is shaped. As the magnetic field from the stator coil reverses with each cycly of the AC supply, the reversal of magnetism spreads progressively through the specially shaped iron in such a way as to give it a twist.<br />
<br />
A '''brushless motor''' is in fact just a synchronous motor driven by an electronic circuit to drive the stator coils and so create the rotating magnetic field.<br />
<br />
===Stepper Motors===<br />
<br />
Often, there is a requirement for a motor which, instead of turning continuously, can be commanded to turn by a predefined amount and stop. An example is the motor which drives the paper feed rollers in a printer. These must advance the paper by the width of the print head and stop after each row of pixels is printed. Similarly, an analogue quartz clock or watch usually steps its second hand on by a second every second. Stepper motors are used in both cases.<br />
<br />
There are different configurations but the simplest and easiest to understand consists of a stator comprising two coils at right angles, and a permanent magnet rotor within them. Initially, one coil is energised and the permanent magnet lines up with its magnetic field. If the other coil is also energised the magnet will turn 45 degrees to a position between the two, and complete the 90 degree turn when the first coil is turned off. Re-energising the first coil in the opposite direction will cause the rotor to continue another 45 degrees, and so on. In this way, a shaft attached to the permanent magnet can be turned 45 degrees at a time as needed. By reversing the sequence, it can be turned in the reverse direction if this is required.<br />
<br />
==Fault finding and Repair==<br />
All types of motor can jam if the bearings become clogged with dirt or dust, as can easily happen in power tools. Shavers, electric toothbrushes and kitchen appliances can seize up through ingress of water etc. Cleaning may be all that is required, but in the case of water, preventing the same happening again can be challenging. Investigate whether replacement seals are available. A seized bearing can often be freed with WD40, and a ball race clogged with dust can be cleaned with white spirit, but in either case, it's important to lubricate with suitable oil or grease once clean and dry, as neither WD40 nor white spirit are good lubricants.<br />
<br />
Small motors designed to run off batteries are often not designed to be taken apart though it may be possible to do so by bending the lugs that secure tham. Larger ones such as those intended for running off the mains can often be disassembled by removing two long bolts running through their length. In the case of DC and universal motors, on reassembly you will need to remove the brushes or hold them out of the way in order to slide the rotor into place with the commutator between them.<br />
<br />
If seized up, a motor draws a heavy current. It is designed to do so momentarily as it starts, but if prevented from turning it may overheat and damage the insulation, and in the worst case, burn out the windings. A burning smell is a strong indication of trouble, and damaged insulation may result in an inconsistent speed. If there's any evidence of deterioration of insulation the motor should be scrapped. (Specialist firms rewind large industrial motors but it's unlikely to be cost-effective for a domestic motor, nor a simple task to undertake yourself.)<br />
<br />
If there are no visible signs of deterioration it's worth testing the windings with a [[Glossary:Multimeter|multimeter]] on a [[Glossary:Resistance|resistance]] range. A low reading is normal as the applied [[Glossary:Volt|voltage]] is limited not by the resistance of the windings but by the dynamo effect which always opposes it.<br />
<br />
A common fault with DC and universal motors is wear of the carbon brushes which make contact with the commutator, or a dirty commutator. Excessive sparking is a sure sign that maintenance is urgently needed. The brushes are normally pressed against the commutator with a spring, but they may cease making good contact if they wear right down or if they are prevented from sliding down within their housings as they wear. Replacements can be obtained but you will need to take care selecting the right size. Replacements may be available for your specific make and model of appliance, otherwise, carefully measure the old brushes and their housing and you should be able to find suitable replacements online. If a brush wears right down to the spring the sparking is likely to permanently damage the commutator.<br />
<br />
Some professional and high-end DIY power tools have brushes which contain an embedded spring-loaded plastic pin. When the carbon wears down to its limit the pin is released, pushing the worn out brush away from the commutator to prevent further wear and permanent damage. Professionals have been known to discard expensive power tools which have suddenly stopped working for this reason - an easy fix if you can recognise the problem.<br />
<br />
Shaded pole induction motors are usually very reliable, but capacitor, thermistor and centrifugal mechanisms for starting may develop faults. If there is a capacitor it may show obvious signs of distress, otherwise test it if you can. If nothing else, you can use a multimeter on a resistance range to test that it isn't shorted.<br />
<br />
An electric motor contains lots of copper and iron - make sure you recycle it responsibly!<br />
<br />
[[Category:Theory]]</div>Pleriche