Chosen Solution
I dropped my iphone and smashed the display. Everything still worked, but with a cracked screen. So I bought a replacement screen and installed it. At first it worked perfectly. Then it started taking some seconds to turn on. Then it stopped turning on entirely. The failure made me suspect the screen was dead. So, I opened it up and connected the old screen, worked immediately. Put the new screen in, nothing. Old screen in, all good. So, concluded that the new screen died. I went about moving the ear piece, and reassembling. Screwed it all together and … nothing. Now neither screen works. It feels like I’ve done something (unknown) wrong, and killed two screens. Anyone got any ideas what I’m doing wrong? How could I have killed a display by just screwing everything back together again?
The earpiece is a different connector than the display. So I think this might not be the problem. My guess is, that from plugging and unplugging the display you might have pushed the connector pins too far into the connector which results in no connection and is often the problem. Or you might have loosened a filter component next to the connector. Visually inspect the board around the display connector (the bigger one) and look for weird looking small components. To inspect the connector itself you need a microscope to see if the pins are pushed in but those can be pushed back with a thin tool. At last you can try to measure the display connector on the board with a multimeter in diode mode and see if there are wrong values. So to sum it up, the display are probably not defect but the connector on the board might be. But you need the right tools and expertise to fix that. If that is not option for you, try to find a third display to verify that the problem is with the board.
