Chosen Solution
I really hope someone can help. I recently fitted a new screen to a iPhone 7 but upon start up the phone got to the apple logo and then restarted again. After searching the threads I thought it could be the audio ic which I tried to reball but there was no change so I put the phone aside. Today I had another iPhone 7 and thought I could use the new screen however, the same thing happened with this second phone i.e bootloop ( the phones restore normally but then revert to a boot loop ) I had a look at the screen cable under the microscope and found a bit of solder touching ground and the top four pins ( I think they go to pins 1,2,3 and 4 on the motherboard ) I have checked the board and discovered at least pin 2 is short to ground which the schematics show as “I2C_Disp_EEprom_SDA_Conn” I have checked FL4741, C4741, C4731 and FL4729 and all are shorted. Can someone please help and give me some idea where the short is possibly coming from as I have two customers iPhone 7’s to repair. Thank you in advance
If I understand correctly, the same, new replacement screen caused identical boot-loop issues on two separate phones? And you found that there was poor soldering on one of the connectors causing a solder bridge? If that is correct, then you should either fix the poor soldering on the screen connector or have your supplier replace/refund the screen. As for the short, is I2C_Disp_EEprom_SDA_Conn shorted when the screen is connected only or even without a screen connected? You went pretty quickly from replacing a screen to reballing the Audio IC without trying a known-good (or even the original) cracked screen. Perhaps you did other troubleshooting in the interim. If you are proficient at reballing mid size IC’s, then we can eliminate that as a variable…otherwise, it is always possible that that caused issues as well. Based on your description of the issue, I would just focus on getting a known-good screen and work from there.
