Chosen Solution
Hi all, hoping for some suggestions. Bought a non-working iPhone 6, got it home put it on known-good battery & dock connector, drawing 900mA on my USB ammeter but wouldn’t come on. Connected to iTunes, was able to do a complete DFU restore including installation of iOS 11 and went right through no problems. However at no time did the screen display anything and also I felt heat around the screen ribbon connector area, so once I got it restored and after checking with a flashlight to be sure that it wasn’t just no backlight I took out the board and had a good look around under the microscope. I noticed straight away that a filter FL2024 was missing so tinned the pads, took one off a donor board and replaced it thinking perhaps that somebody knocked it off when replacing a screen. All seemed to go well with no problems, looks good under the microscope. However now when I put the board back in a known-good housing & battery the screen still doesn’t come on but the phone’s amp draw is fluctuating all over the place (but never gets above 500mA) when it had been steady before at a typical boot current. On the positive side the heat appears to have gone but that’s not much consolation! One last thing; when I first opened it to have a look there were only 2 screws in the metal shield covering the screen connectors and the middle one which should have the smallest size of screw in it had a slightly larger one (not the really big one in the corner but too big anyway). I haven’t done a lot of voltage testing on it yet (it’s 1am here!) tho I will tomorrow, but would be really grateful for any hints or suggestions as to what might be wrong here. Thanks
It sounds like whoever had this phone couldn’t get it repaired and now you’ve inherited this mess. I would inspect the screw holes to see if there isn’t any, even light , Long Screw Damage. Then I would start probing Chestnut and the voltages it generates. The missing filter smells like some tried to repair the device, not really knowing what they were doing. I would closely inspect the backlight circuit as well. Report back on what you find.
