Flat screen TVs and monitors

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This page will cover flat screen TVs and computer monitors.



As with all mains electrical devices, dangerous voltages may be exposed when opened. Be aware that capacitors can store a dangerous voltage long after power has been disconnected.

Classes of device

There are several types of flat screen (flat panel) TV's and monitors, well summarised in Wikipedia under Flat-panel display.

For completeness we should mention the original CRT screens which were the norm from the first days of television to around the 1980's when plasma and newer technologies started to replace bulky CRTs. CRTs also required very high voltages 10-20kV (10,000-20,000 Volts) which meant repairing required great care.

So what is the distinction between a TV and a monitor? Both display pictures and provide sound, the distinction comes from the source of the picture and sound signals. A TV has an RF tuner (receiver) that the users controls to select the programme they wish to view. It's signals arrive by radio from a remote transmitter and it will have an antenna connected to receive those signals.

A monitor does not have the tuner, instead it is fed from an external source, typically a PC/laptop via cables. That said, a monitor can be fed from a freeview or satellite TV set-top box and a tuner can be used as a computer monitor, and either can be connected to a DVD or video player or a games controller.

A smart TV perhaps forms a third class of device, containing both a tuner and its own computer with an Internet connection. Furthermore, you may be able to "cast" a video stream to it from your smartphone or tablet, via WiFi or Bluetooth.

The first step is to clearly identify what type of TV/monitor you have because that will help you determine what the basic electronics blocks are. Usually it is fairly obvious but if unsure search the internet for information about the make and model type. The most useful model information is usually found on the back or underneath of the item.

Diagnosis and Fixing

CRT TVs and monitors

Fixing these requires a very clear awareness of high voltages and any opening and repair should be done with full knowledge of how to identify the danger areas. The CRT also requires care with handling, dropping the glass tube which has a vacuum inside can result in an explosion of glass particles which will cause serious injury. Not a job for a repair cafe event.

Plasma TVs and monitors

LCD TVs and monitors

LED TVs and monitors