Chosen Solution
yesterday I tried to repair my iPhone 7 display. after I replaced the screen of the iPhone, I didn’t get an image on the screen (the only backlight was functioning). after swapping back to the broken screen the iPhone showed an image again. I tried to use a known good screen, but I had the same issues as by the first screen replacement. the broken screen that needs replacement is an aftermarket screen, so I don’t think it has anything to do with my replacement screen. I’ve tried to hard reset the phone, put it in DFU mode, and completely reinstalling the os. this didn’t work either. I’m at the point where I don’t know how to solve this problem. has anyone an idea how to fix this?
This sounds like you may have a logic board issue and certain screens are more or less “demanding” in regards to current draw. Take a close look at the screens your are trying. There isa difference between an original screen, a good quality aftermarket or a cheapy screen. Ironically, some cheap screens work really well and in other cases, they don’t work well at all. If you are a shop, or have access to multiple screens, try to see if the is a relationship between the type of screen and the problem. IMHO, if an original or high quality screen doesn’t work (assuming no flex or connector issues), then you may have a partially damaged LCD drive or backlight circuit.
If it’s not a screen problem, then it’s most likely a board problem. You need to check the board carefully. First the boot current and then the display circuit and backlight circuit.
