Display O.K. or NOT?

Hi @kumaran123

If the phone shows signs of being “alive” e.g. audible sounds when turning on or responds when connected to a computer etc, but there is no display, temporarily replace the display with a known working compatible display and check the result.

If the replacement display works test the phone to see what works and what doesn’t work.

You then have to go on the results to see what else if anything may be wrong with the phone e.g. the display might work but the touchscreen doesn’t or there is no audio or no signalling etc.

If everything works then you know that the only problem was the original display

If the replacement display also doesn't work then there is a problem with the motherboard that either affects only the display (and you know that the display itself is OK) or there are more problems as well e.g. if the display is not working shine a torch at an angle close to the screen to check if there is an image at all when the phone is on. If there is then there is a problem with the backlight power feeding the screen. If there is no image then there is a problem with the signalling and power to the screen. Board level repairs would require access to the schematics for the board and experience in micro soldering to do any repairs etc.

Once you have fixed the problems on the board and the phone is working with the replacement display, you can install the original display and check if the phone now works or not with it, to see if the display is faulty or not.

To my way of thinking, all fault finding in electronics comes down to finding out what is working or not when it should be working and if it is not working why isn’t it.

Broadly speaking with mobile phones you have to be able to “see” to know what is working and what isn’t and go on from there.