Chosen Solution
I replaced the audio ic on a iPhone 7 and after i put the phone together, the touch doesn’t work. I already tried a known working screen to rule out that problem and it still doesn’t work. I took the logic board out again and only plugged in the battery, charging port and screen and the touch worked fine then. I found that weird so i started to gently press on the logic board and i barely have to press it a tiny bit and the touch stops working immediately. If i release the pressure, the touch works again. I replaced the Audio ic once more just to be sure i wouldn’t messed it up there and i still have the same issue. I’m assuming i might have shorted or overheated something while replacing the audio ic but i can’t find anything. Has anyone else run across this problem or anyone some tips and ideas on where to look for problem?
I have never run into this problem after an audio IC repair. It is most likely around the connector area there are a few filters on both sides of the board that might not be making good contact. Also check the two power lines for touch when it is not working and also that no pins are pushed into the plastic of the connector.. The ideal tool for this diagnosis would be the iBridge. You didn’t mention where you put pressure on the board for touch to return, if it is on the CPU than you will need to re-ball it.
