Malfunction Phenomenon
iPhone 7 Plus Charging Issue. The capacity of the battery showed 1%, but it jumped to 16% when plugged into the charging cable.
Trouble Shooting
According to the malfunction phenomenon, we can conclude that the problem was from the charging circuit. There are 5 main components and chips in this circuit.
We can disassemble the phone and measured the voltage values on the battery connector with a USB cable connected.
The measured value was just 0.69V, which was abnormal. The normal value should be around 0-4V and keep on changing when charge.
We continued to check the voltage PP5V0_USB on C2101, the value was normal.
Based on repair experience, try to replace a new USB chip U4001 and test again. Before we connected with a USB cable to charge, the capacity was 11%, after charging for 5 minutes, the capacity turned to 13%, the problem was resolved.
Tips, for this kind of issue, related to battery data
- if the voltage on the battery connector was abnormal when charging, we have to check the USB IC and relevant components
- but if the voltage was normal, we have to check the battery data feedback line on pin3 and pin 2 of the battery connector
iPhone 7 Motherboard Repair Course
