problem is it is bootlooping

Question

iPhone 6

2014년 9월 19일에 출시된 이 4.7” 스크린 iPhone은 iPhone 6 Plus의 작은 버전입니다. 모델 번호 A1549, A1586 및 A1589로 식별됩니다.

4994 질문 전체 보기

daniel @tech_ni

평판: 34.6k

10

22

44

게시일: 2018년 3월 28일

옵션

problem is it is bootlooping

@refectio have a liquid damaged 6 here atm, the guy that dropped it off does some repairs, when i got it the shields were removed and he said he went over it with ipa. the problem is it is bootlooping l1604 coil was damage so i removed it and still bootloops. on dc power its not going over 0.42 amps i have tried to measure voltage around pmic but power drops out and i cant get a good reading. cant seem to find anything shorted to ground. vcc_main seems fine and so does pp5v0_usb and pp_vbat

답변되었습니다! 답변 보기 저도 같은 문제를 겪고 있습니다

좋은 질문 입니까?

예 아니요

점수 1

댓글 달기

답변 1개

선택된 답변

Minho @refectio

평판: 221.4k

15

289

807

게시일: 2018년 3월 28일

옵션

The L1604 coil is for the speaker amp so it shouldn't have anything to do with any boot looping. If the phone is going to .42A, then it's getting into a more serious part of the boot cycle. Have you checked the main PMIC outputs for shorts/diode mode? Focus on the main lines such as PP1V2*, PP1V8*, PP3V0, CPU & GPU.

Also check the RESET_1V8_L line. Make sure it is properly pulled up to PP1V8.

해당 답변은 도움이 되었습니까?

예 아니요

점수 3

댓글 8개:

is pp_gpu supposed to be ground at both side as i have checked it and caps on that line are beeping on both sided but it does that on a working board i have so guessing it should. i took some caps and coils off that line and the phone just stayed on apple logo with no bootloop. then put 4 caps and 2 coils back and its back to bootloop and hits a max of 0.52 amps. nothing else apart from that line seems short, im going to replace tristar to see if it makes a difference

daniel 의 2018년 3월 28일

PP_GPU is a low resistance line, typically in the 20-60 Ohm range so it will beep in continuity mode. You should check the meter to see what the actual measurement is.

Minho 의 2018년 3월 28일

dc power now hangs around 0.11 with no image or back light. only reading i get from around pmic is 1.7v on the pp_gpu cap cant seem to get many other voltages around other areas

daniel 의 2018년 3월 30일

PP_GPU shouldn't give you 1.7V. You may want to remove the PMIC, probe the pads while it's off to see if anything is weird and try a new one if there are no shorts on the outputs. Check all the main outputs.

Minho 의 2018년 3월 30일

sorry it was PP1V8_SDRAM that was 1.7v. pp_cpu i get 0.755v

daniel 의 2018년 3월 30일

댓글 3개 더보기

댓글 달기

is pp_gpu supposed to be ground at both side as i have checked it and caps on that line are beeping on both sided but it does that on a working board i have so guessing it should. i took some caps and coils off that line and the phone just stayed on apple logo with no bootloop. then put 4 caps and 2 coils back and its back to bootloop and hits a max of 0.52 amps. nothing else apart from that line seems short, im going to replace tristar to see if it makes a difference — daniel
PP_GPU is a low resistance line, typically in the 20-60 Ohm range so it will beep in continuity mode. You should check the meter to see what the actual measurement is. — Minho
dc power now hangs around 0.11 with no image or back light. only reading i get from around pmic is 1.7v on the pp_gpu cap cant seem to get many other voltages around other areas — daniel
PP_GPU shouldn't give you 1.7V. You may want to remove the PMIC, probe the pads while it's off to see if anything is weird and try a new one if there are no shorts on the outputs. Check all the main outputs. — Minho

iPhone 6

problem is it is bootlooping

답변 1개

귀하의 답변을 추가하세요