TV Has No Picture
Most likely cause is backlight failure
This is the most common problem with TVs today.
The backlights are bright LEDs on strips behind the screen, or sometimes along the edge of the screen.
They are usually 3 Volt or 6 Volt and connected in series, so if one goes open circuit, this will break the current to them all very similar to the old fairy lights where you had to check each one to see which one had failed. The TV will have to be dismantled and the screen removed to get at the backlights.
Before replacement strips were widely available, the faulty LED, or more would be replaced, but this proved unreliable as the other LEDs were also likely to fail at some point. It eventually became possible to obtain complete sets of LED strips that made a lasting repair.
The cost of replacement varies with screen size as well as make and model. You are looking around £85 for a 32" and £120 - £200 for 40"- 55". £150 is around the average.
How can you tell if it's backlights?
Sound will usually still work. If you look closely at the screen you may see an outline of an image as the daylight hits the screen. You could also try shining a torch at the screen to see if an image is there, but this may not be noticeable with some screens.
Blue or Purple Screen
Again, the backlights would need replacing. Instead of emitting white light, the LEDs have turned colour due to extended use. This is gradual and it may be that someone else notices it before you do.
A complete replacement of LED strips would make the TV like new again.
When it's not backlights
If you turn the TV on and you notice the screen brightens slightly but is blank, or you can see light when you look through the vents on the back of the screen, then it looks like the backlights are OK.
This is not so easy to diagnose as it could be the Tcon board [ timing control board ] This controls when each set of pixels turn on. It may be a case of replacing the Tcon board. These are not standard boards.
The exact one to match the screen has to be fitted. TVs that are the same make and model can have different Tcon boards in them, which is a headache for engineers. Some Tcon boards are very easy to obtain, others are difficult to get hold of. It may be possible to repair a Tcon board.
Expect to pay around £70 for a Tcon, but could be higher depending on the model.
Some screens have the Tcon built in, so not as simple as swapping the board. Hope that the Tcon section can be repaired, or TV is beyond repair.
It could also be the main board causing no picture, which would be expensive, around £100 mark.
It could also be the screen itself that is faulty which would make the TV a write off.
At least the parts could be used to get somebody else's TV going !
