Customer came with an iPhone 5S which has strip line on the screen. First I replaced it with several new screens to make sure it’s not the screen defection. My customer also told me that he never drop his phone while this strip lines showed up on the screen unexpectedly.
I disassembled the phone and took the motherboard to have a check. Finally I found that the resistor values on pin 1 and 2 of J5 on motherboard are not correct, which connecting U23 and U15 which are responsible for power supply for screen LCD backlight and touch function. I replaced both U15 and U23, then the issue is fixed.
I recorded the video clip of fixing this iPhone 5S issue and posted it on Youtube, please check it if you like. BTW, I forgot to recording some steps of measuring the resistor values on pin 1 and 2 of J5 and replacing U23.
