iPhone 7 not charging, already replaced both Tigris and Tristar chips
Hi guys, I have an iPhone 7 here. The customer shorted the motherboard while cleaning the charging port. The phone was totally dead when he gave me the phone. Based on what the customer described, I believe the charging system on motherboard must be shorted. I removed both the Tigris and Tristar chips, the phone was able to turn on properly. I knew my judgement was correct. Then I installed a new Tigris and a new Tristar chip (610A3B). However, the phone was still not charging. I tried a known working charging flex, same result, the phone was not charging. When put the phone on charge, the phone recognised the USB lead (as it turned on properly), but no charging symbol on the phone.
Upon further testing, I found 5v arrived properly at Tigris, but 5v on Tristar is missing. I guess the Tristar regulator Q4001 was damaged as well, so I replaced the Q4001. Now 5v detected on Tristar chip. When put it on charge, the phone recognised the usb lead, and charging symbol appeared. To my surprise, however, although the phone showed charging, it’s actually not charging at all. Zero amps getting into the phone.
I did the Tristar twice, same result. I wonder, apart from the Tristar, is there anything else I can check?
Update: I also replaced the Q2101 with a new one, which is responsible for the communication between the Tigris and the battery, made no difference. The phone has 5v on both Tigris and Tristar, computer recognises it, it can connect to iTunes, the voltage of the components around the Tristar and Tigris are all correct, but the phone just wouldn’t charge. :(
I guess it’s the CPU or big PMIC. :(
Is this a good question?