1. Carefully disassemble the iPhone 7 and disconnect the battery. Put iPhone attach to DC energy provide, the boot present is customary, however the display screen nonetheless black.
2. Carefully disassemble the display meeting, and substitute with new one. Once once more put iPhone attach to DC energy provide after which energy up, the boot present shows most often, however iPhone nonetheless is going and not using a display. So, we suspected that this downside is brought about by motherboard backlight circuit broke down.
3. Teardown the iPhone, take out the motherboard. Measuring the grounding resistance worth of J4502 with multimeter, the knowledge is customary, which presentations that the backlight circuit could also be customary.
4. Because the backlight sign is attached at once with backlight IC U3701, now we will pass judgement on that the backlight IC U3701 broke down.
5. Paint some BGA Paste Flux, take down the backlight IC with Hot Air Gun at 320 levels. Now, we’d like to blank the tins, use soldering iron blow it first, after which use PCB Cleaner to blank it once more.
6. Paint some BGA Paste Flux once more, align the backlight IC in the proper place, after which solder it with sizzling air gun. Cooling the motherboard, after which use PCB Cleaner to blank it.
At final, collect the iPhone smartly, after which activate iPhone to check, the white Apple brand seems easily. The upkeep finish!