Chosen Solution
hi, I have an iPhone 6 from my daughter no boot. It stop power on after charging with third party charger, cable was burn…. Since i replace U1700,:
- it was stucked on apple logo if i hold power button during 2sec.
- it’s not recognize by itune
- plug and unplug to an official charger is detect by the phone. i try with new dock flex, same result. There is no short on vcc_batt and vcc_main i test this voltage: PP_CPU 0.85V PP_VAR_SOC 0.9V PP_GPU 0V ???? PP1V8_SDRAM 1.8V PP1V2_SDRAM 1.2V PP0V95_FIXED_SOC 0.95V PP1V8 1.8V PP1V2 1.2V PP1V2_OSCAR 1.2V PP1V8_OSCAR 1.8V PP1V8_GRAPE 1.8V RESET_1.8_L 1.77v—- 0.7v before u1700 replace is it normal that pp_gpu has no voltage before boot(some people say that)? i test the line but no short (63 Ohms) do you thinks u1700 is not replace correctly ( it’s my 1st microsoldering) Do you think i need to replace PMIC? since there is no short on pp_gpu do i need to take off L1213-L1214 to continu testing ? I dont know what to do first… If it’s normal that pp_gpu has no voltage before boot i need to verify u1700, if not i need to replace PMIC , is it right ? thanks ps: never third party charger again :-)
PP_GPU only comes on when the display turns on. So if you want to test it, you either need to connect a power button flex and manually push the button or have a dock flex installed and plug in a charger. If you go the power button route, PP_GPU will only stay on for about 20-30 seconds. With 63 Ohms of resistance, it is not shorted. There are also other power lines generated by the PMIC (PP3V0_NAND, PP3V0_TRISTAR etc.); have you tested those as well? I suspect your Tristar replacement did not work.
