How to fix dead iPhone 6s plus?
My iPhone suddenly stops working and when I pushed the lock button it asks to connect to iTunes .so connected to my laptop to do restore but it failed! so I tried again but now the laptop wouldn't detect my iPhone and now its dead. then I went to repair shop he said "I changed the power ic and it worked but when I tried to restore it went dead!" he said it cant be fixed the problem in the CPU.
I don't know if he was honest with me so I tried to troubleshoot by myself.
I connect the iPhone to the power supply with 3.8v when I pushed the lock button it read constantly 0.2 amps.
the battery voltage was 2.6v but after charging it became 3.7 v
I connect it to the USB charger and measure the voltage on the battery connector it was 3.7v
I tried to do some measurement depending on the schematic but I don't know where to start. but I noticed that the test point TP1120 which I suppose connected to the PP_GPU read 0 v .and the multimeter beeps when I put it on the beep mod!
so is the PP_GPU shorted? any idea what to do next?
and how to test the PMU?
I'll be grateful for any answer