problem is it is bootlooping

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iPhone 6

这款4.7英寸iPhone于2014年9月19日发布，是iPhone 6 Plus的缩小版。

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daniel @tech_ni

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发帖于: 2018年3月28日

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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

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Minho @refectio

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Refectio - Mail-in Micro-Soldering Repairs & Data Recovery

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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.

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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

由 daniel 完成的 2018年3月28日

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.

由 Minho 完成的 2018年3月28日

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

由 daniel 完成的 2018年3月30日

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.

由 Minho 完成的 2018年3月30日

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

由 daniel 完成的 2018年3月30日

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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

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