Pièces détachées
Les pièces détachées sont souvent nécessaires lors de la réparation d'articles électriques ou électroniques. Nous examinons ici les différents types de pièces détachées et la manière dont elles peuvent être obtenues.
Types of Spare Parts
Original Parts
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.
Third Party Parts
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.
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!
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.
Refurbished and Remanufactured Parts
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. When buying refurbished parts, it is good to look for a long warranty period and to buy from a reputable and accountable manufacturer.
Salvaging Parts
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.
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.
See below for an overview of spare parts and where to find them.
Where to buy
Buying from manufacturer
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.
Spare parts suppliers
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.
Buying from eBay
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.
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).
Potential issues and how to overcome them
Identifying fakes
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.
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.
Software Locks
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.
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.
More things to consider when buying used
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. 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.
BUT: If only second hand parts are available, don’t hold your breath - look for a returns policy and good seller feedback record.
Spare Parts overview
PC components
Backlight
Found in LCD displays like TVs and PC monitors.
- Illuminates the images produced by LCD
- Strips of LEDs found behind the LCD and diffusion layers inside the panel housing
How to test: Using a backlight tester tool (a power supply automatically adjusts the voltage and current depending on the load applied. Or using a multimeter to test correct continuity of each LED separately
Salvageability: Individual surface mounted LEDs can be removed with hot air/reflow stations and used in strips with the exact same specifications.
Buying advice: Available second hand and sometimes brand new via ebay. Expect only a 30 day refund policy.
Hard Disk Drive
- Main large format mechanical storage device
- Different physical formats include older 3.5” (diameter of disk itself) in desktop PCs, smaller 2.5” in laptops and smaller variations like 1.8” found in iPod classics.
How to test: General slow reading/writing data after 5 or so years indicates failure. Can use software like hard disk sentinel to test the health of the drive. Loud/clicking noises indicate physical damage.
Salvageability: A USB/SATA enclosure can be taken from an external HDD and reused with another drive. Mounting screws are very useful.
Buying advice: Check connection - (SATA on most relatively newish devices). Check characteristics: i.e.performance (WD black) or desktop (WD blue), NAS storage (WD red) or surveillance (WD purple). Get best type for requirements. Pay more for faster speeds and bigger capacities. Buy though respected outlet with long warranty and good reviews.
Internal switched mode power supply
Found inside most mains digital devices: TVs/Desktop PCs/DVD players etc.
- Exists to convert mains AC voltage to DC voltages required to run digital systems.
- Mains cable will usually connected directly to this
- Bigger size components will be present
How to test: When turned on look for output voltages with a multimeter. Sometimes they are marked on the board.(or on casing with PC) Otherwise look for typical outputs like: ON: 12V/24V Standby: 5V Control Signals: 3.3V Desktop PSUs can be tricked into turning on without a motherboard by connecting two pins with a paper clip.
Salvageability: Intact and working desktop supplies can be used (for the rest of their lifetime) in other PCs. Faulty boards can be desoldered for reusable parts like: capacitors, diodes, resistors, connectors, ICs and coils.
Buying Advice: Desktop PC enclosed PSUs usually follow ‘ATX’ standard - and are sold new - match wattage. Buy though respected outlet with long warranty and good reviews. Internal PSU boards are usually bespoke and only available second hand. Match part numbers and device model number. Check pictures that connectors and components and layout are the same. Check eBay and look for high ranking sellers. Expect only a 30 day refund policy.
Motherboard
Sometimes called mainboard or logic board)
- The main computing brain behind any digital electronics
- Connects most of the electronics together
How to test: Often diagnosed after all other possibilities have been eliminated. With schematics voltages can be traced and faulty components found with some difficulty!
Salvageability: Faulty boards can be desoldered for surface mount (SMD) components with hot air/reflow stations but components are often more bespoke and less reusable. Connectors like HDMI/DVI/USB are more reusable but still come in many different variations.
Buying advice: Desktop motherboards are also sold new - check compatible with existing parts with an online spec checking tool - may be best to buy new CPU a+ RAM. Buy though respected outlet with long warranty and good reviews. Internal motherboards and laptop motherbaords likely only available second hand if at all - again match part numbers and device model number Check pictures that connectors and components and layout are the same.Check eBay and look for high ranking sellers. Expect only a 30 day refund policy.
Optical Disc Drive Drive CD/DVD/Blu Ray
Mechanical drive for reading disc format storage.
How to test: Is it reading the disk? If not then laser damaged or dirty. Does the draw open and close correctly? If not then drive belt or gears need cleaning or replacing
Salvageability: Drive belts and gearing systems can be salvaged and reused in similar kit if in good order. The motors are useful - especially to modify hornby ringfield motors!
Buying advice: In desktop PC sizes and connections are standard. Buy though respected outlet with long warranty and good reviews. Otherwise check model number and connections.
RAM - Random Access Memory
- A computer's temporary ‘thinking’ memory - stores data used for running of programs.
- Removable on plastic stips in desktops and laptops and soldered into motherboard otherwise
How to test: In desktop beeping noises may specifically indicate ram failure. Can test fully using Memtest86 software in PC.
Salvageability: none
Buying advice: Match original specifications like form factor: desktop or laptop and (DDR2/3/4) and timings (clock cycles) - just needs to match motherboard specification.
TCON/ Timing control board
Found mostly in LCD TVs and other display.
- Specifically controls the video signals going directly to the LCD panel
- Connects to the motherboard and LCD panel
How to test: Look for display deformaities when TV is on. 12V should be present SMD fuse can be tested for continuity
Salvageability: Faulty boards can be desoldered for surface mount (SMD) components with hot air/reflow stations but components are often more bespoke and less reusable.
Buying advice: Also only available second hand if at all - again match part numbers and device model number Check pictures that connectors and components and layout are the same.Check eBay and look for high ranking sellers. Expect only a 30 day refund policy.
Smartphone components
Smartphone Motherboard/Logic Board
Main computing board on phone. Occasionally split into multiple pieces.
How to test: Often ruled out after process of elimination - especially after new battery and factory reset. Faults with charging circuits can be found with sharp multimeter probes and looking for very hot components.
Salvageability: Good motherboards can be salvaged from phones with others faults. But beware that after dropping a phone and breaking the screen the motehrboard might have also been damaged.
Buying advice: Match part and especially device model numbers as there can be different variations with the same phone. Usually only available second hand or ‘refurbished’, but refurbished can be meaningless or untrustworthy here. Read descriptions and message the seller for information. Avoid boards that have just been ‘reflowed’ as this is not a long lasting fix.
Smartphone Screen /LCD/ Digitiser
A outer layer, an LCD (display) layer and a digitizer(touch) layer.
How to test: Sometimes just the outer layer is cracked and the display and touch are not affected. Other times LCD or digitizer are cracked and the display is distorted or lost completely
Salvageability: Often good screens can be salvaged from phones with other faults. But should be disposed of correctly when at end of life.
Buying advice: Match phone model exactly. If just the outer layer is cracked sometimes this can be removed and replaced seperately - but is usually very difficult to do. The price for full displays varies phone to phone - can be almost the cost of the phone second hand. Usually just third party options available to unofficial/certified parties.
Batteries
CMOS Battery (CR2032)
Lithium button cell battery found on motherboards - used to store bios information like date and system settings. (removing can fix some errors).
How to test: Working will be 3V on the multimeter. Bios gives error message if discharged.
Salvageability: Can be used in other device that needs exact same type or for another motherboards CMOS.
Buying advice: Buy new - can be bought anywhere.
Lithium Battery
Found in most modern portable devices. Smartphones/laptops/speakers.
How to test: Expect them to hold less charge and take longer to charge after about two years. Often older batteries can cause unexpected shutdowns too.
Salvageability: Should be disposed of correctly when at end of life.
Buying advice: Match battery model number and device model number. Check connections and size/shape of connections. Buy new from online. Sometimes both a third party and original option are available. Some types are very expensive.
Buttons and switches
General Mains Internal Switch
Many different types in different devices - to break flow of current and interface equipment.
How to test: Examine for physical defects and burnt marks or melted areas. Test for continuity through terminals in different positions.
Salvageability: Can be reused in other devices wth same requirements if working. But if damaged don’t reuse.
Buying advice: Look for the same part number and specifications. Pole: electronically seperate switches controlled by a single mechanical switch. Throw: number of separate wiring path choices other than open.
Input/Output Connections
Buttons and connectors found in front of desktop PC case.
How to test: Test for continuity with multimeter.
Salvageability: Individual switches, LEDs and connectors removed from their housings can be reused in other things.
Buying advice: Usually just available bespoke with PC case or otherwise second hand.
Thermal Switch /Reset/Cutout/TCO
A safety cut out device that can often be reset - protecting against temporary one time overload situations.
How to test: Test continuity - if failed completely will not let current pass through.
Salvageability: Could be reused in similar devices if still working.
Buying advice: Match model number / device model number. Found new on ebay but often found on more reputable trade sites.
Audio components
Internal Motherboard BIOS Speaker/Buzzer/Alarm
Sometimes but not always to be found connected in the I/O area - heard giving audible information about hardware on boot.
How to test: Should give one small short beep to indicate working PC.
Salvageability: Working buzzer is standard and can be used in other desktop PC.
Buying advice: Follow generic standard so can be bought online new or used.
Speaker Drivers / Headphone Speaker drivers
The actual magnetic speaker.
How to test: Test resistance matches markings printed on the side. Check for burn marks. Keep clean and away from small bits of metal that can get stuck inside and ruin the sound.
Salvageability: Can be swapped in and out of other devices requiring the same resistance.
Buying advice: Match resistance, size, and model numbers. Depending on device type may be found new, second hand or not at all.
Cables and connectors
Cables
Pass electrical power and signals.
How to test: Test for continuity - use pinouts if unsure which core is which .
Salvageability: Very useful to keep for fixes and projects. CAT 6 and Scart particularly. Use appropriate type for current rating /application.
Buying advice: Buy new with best possible warranty from trusted source.
External Switched Mode Power Supplies /USB charger
Power supply unit or ‘charger’ for portable devices. Mains AC in DC out.
How to test: Is the light on? (if it has one). Test output voltage with multimeter - will be written on plug (may work intermittently if connection is loose somewhere). Physically inspect - frayed ends will likely cause failure eventually.
Salvageability: Connectors can be cut off working PSUs and the part can be repurposed with a different connection for another application that requires the same spec. Faulty boards can be desoldered for reusable parts like: capacitors, diodes, resistors, connectors, ICs and coils.
Buying advice: For Laptops match model numbers and buy specific and original part where possible. Multi-voltage/switchable voltage supplies can work but are more expensive - check connectors supplied. For smartphones get original for phone or from the manufacturer or with stated certification. Cheaper third party options aren’t recommended. For other general or nonspecific devices match the voltage exactly and ensure the current output is equal to or more than needed (device will only draw what it needs to). Spec should be written on the device. Check connector type matches for size and design. Also check polarity/orientation of connector is right way around - i.e. center positive or center negative.
Fuses
Provides overload protection. Metal wire that melts when too much current is passed through.
How to test: Test for continuity - current should pass if working .
Salvageability: All working types very useful as spares all the time.
Buying advice: Buy new. Check specification carefully. Voltage, Amperage, size, Time delay (T) or fast blow (F)
Mains Plugs - UK/EU
Connection to national mains power standards.
How to test: Check fuse. Make visual inspection for burnt or melted areas. Make sure wires are attached to terminals in the correct way without.
Salvageability: Keep ‘em all
Buying advice: Buy new and cheap from a trusted trade shop.
Other
12V PC Fans
Found inside desktop PC case.
How to test: Test with seperate power supply. Fans will get loud towards end of life.
Salvageability: Older fans that have got too noisy can be used with 12V PSU to make extractor fans or personal cooling fans.
Buying advice: Check size matches - i.e. 80mm/100mm/120mm/140mm. Buy new from reputable shop with long warranty and good reviews.
Heating Element
Resistance of electricity passing through the element creates heat.
How to test: First test for continuity. If good then calculate expected resistance using ohm's law and test to see if the result is the same. If not then the element is likely bad. Also look for physical damage.
Salvageability: Unless element is known to be working as well as relatively new and not full of scale it could be reused. Otherwise dispose.
Buying advice: Buy new and unused. Elements are available for more expensive or ‘serviceable’ devices like electric showers via trade sites but often not available for cheaper products - cost of this part is often the majority of the devices total expense.