Chosen Solution
Hi, I received an iPhone 6S from a customer that said that their screen and battery need replacing. I replaced both of those but when you turn the phone on it boot loops. I plugged it into a USB ammeter and I’m getting 5V and 0.25 amps being drawn when not turned on which looks like it’s charging the battery but when you turn it on it boots but doesn’t charge. It drops to 0 amps when booting and the CPU area gets slightly hot but stops when booted. When not plugged into a charging cable and boot looping the CPU area gets really hot. Would appreciate the help Thanks @refectio
Do you know the history of the device? If it was dropped, repaired, came into contact with water or if the customer was using cheap chargers, then that would help you in your troubleshooting. I agree with A1, try isolating the logic board with a known-good battery and Lightning Port. If it still doesn’t boot, then you definitely have a board level issue. Depending on the history, you could focus on the charge circuit, or probe the PMIC/BBPMU and main voltage rails for additional clues.
I would start with doing an isolation test disconnecting cameras and flexes. If issue is still there I would say Tristar could be the cause.
