This iPhone 6 Plus LCD screen touch function failure after dropping, it was repaired in the local repair shop, but the problem is not solved at all. Now, Vip Pro Shop Team share repair guide for it.
Because iPhone was dropped on ground accidentally, so we judged the touch failure fault is definitely caused by U2402 black touch IC M1 pin sync signal disconnection. It has been repaired, but there will still be the same phenomenon for touch failure, as if the fault was expanded after the last repairs. Remove the U2402, and reinstall the jumper, the iPhone 6 plus device can be used for a while, but there will be no touch function phenomenon, it seems that the problem is not from here. After careful observation under digital microscope, it shows that the inductance and capacitance of J2019 diplay pin get tin explosure. As shown in figure 7-2-2.
Measure the ground resistance, as shown in picture 7-2-3 and 7-2-4, the inductance of signal synchronous is virtual soldered.
So we solder it back with a soldering iron, resistance shows normal now. As shown in picture 7-2-5.
Install the iPhone 6 plus and test again, a day later appeared the display fault again. Measure the resistance of display pin, we find there are no resistance in many parts, gently touch inductor and capacitor with tweezers under the microscope, all of them can be moved, it looks like a large scale is virtual soldered. So we decisively disassemble the whole parts and re welding them again. As shown in picture 7-2-6 and 7-2-7.
Intall the device and test, everything is normal now,the backside seal inductor and capacitor is virtual soldered, which may be caused by long-time air gun blowing operation. The whole maintenance process is finally successful!