Chosen Solution
Hello, I had an iPhone 7 come in DOA. No signs of life, cracked screen, wouldn’t take a charge. After opening the phone, it has no signs of water damage or anything visibly broken. I went through steps of diagnosing the issue. Started with new screen (no fix). Then connected a different battery, nothing. Then decided to replace the charging port. At this point the phone came on, but went into a boot loop. So I disconnected the charging port and reconnected the second battery, and the phone came right on with the original cracked screen. The replacement charging port is an OEM charging port. I am assuming the original battery that is still connected is just very dead as it obviously wouldn’t take a charge from the original charging port. Any ideas?
What happens when you plug the charging flex then plug a charging cable while the phone has successfully booted and is on the lock / home screen? If the phone doesn’t show charging response then it’s definitely the Tristar chip. If apple logo does not appear on either charging ports while battery is unplugged but charging cable plugged in it’s the tristar as well.
Will the second battery take a charge after it dies? I have seen the tristar chip go out or start to fail, which causes this.
