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Hey. So i have a strange case going which i have been working on for a few weeks now. A customer came in with he’s 6S because the phone was dead and not charging at all. I testet this with a USB voltage measure unit and confirmed that the phone does not take any charge what so ever. Naturally i suspected the battery and replaced it. The phone was working fine and was charging like normal. Then the customer comes back with the same problem. I tried charging it while using the USB voltage measure unit and it said 0.00V. So i took the battery out and measured it to 3.26V. The phone needs 3.8V to start but not to charge. I placed the battery on a charging plate (activation plate). I had it there until the battery reached 4.05V and then put it back in the phone. Again phone turned on and received charging fine. I charged the phone to 100% and left it on without charger over night. I came back the day after and the phone was off and again didn’t receive any charging. So i checked the battery voltage again and measured it to 3.03V. I put the battery back on charging plate again and charged it to 4.05V. I put the battery back into the phone, the phone turns on and receives charging just fine. I have tried this with 4 different batteries from different suppliers including the original one. The result is the same every time. I now suspect the Power Management IC. Anyone out there experience this? Anyone knows how to fix it or what to do? Is there something else i can test? Thanks in advance for all answers!
It has nothing to do with the power management IC. Is it drawing any current before prompt to boot? If so how much? You will need a power supply and or multimeter for us to help you. If you haven’t got a DCPS then tell us what the diode measurements are on VCC_MAIN (red probe on ground) We can go from there.
This actually doesn’t sound like a battery issue. The device has a short on the mother board of some kind. This short is causing the battery to drain and discharge past a operating voltage. Once it gets too low the battery won’t charge. Gonna require motherboard repair.
