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iPhone 7 No Power Has 1.1A Short after Power button is pressed

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  • iPhone 7 No Power Has 1.1A Short after Power button is pressed


    I have no history on this device other than what I can see and the fact it went to another shop for a screen (sorry)

    I know it had a drop as the screen was broke.

    Visually not a scratch or dent on housing and no bend (just very light day to day stuff)) so either hit floor face down or took a knock while in a pocket or such. So no big clues there. On the Board no liquid or dents in stickers to indicate force or bend.

    The other shop had tested New parts i.e Battery, charger flex and isolated board and still no power.

    I removed stickers and had a visual inspection and nothing jumped out at me.

    I then connected the board to DC and there was no jump in amps but upon pressing the power button it pulls 1.1A .

    So i now know there is not a short on the main lines but on one of the second lines after PMIC or Pmic its self (correct?) assuming that was correct I looked for issues with caps around the PMIC checking the schematics for the voltage rails generated out.

    I'm concerned there are troll lines here, as I have low readings on the 1st few lines, so wanted to check first is there a line I should check 1st (common fail), secondly which lines are meant to be low and thirdly am I even on the right track of thinking and searching in the right place i have no good board so am a bit lost as to what is correct.

    I did these readings with no power as I didn't want to be feeding power into the short.

    PP_CPU_VAR- 0.004
    PP0V9_SOC_FIXED - 0.017
    PP_CPU_VAR-0.005
    PP1V1_SDRAM-0.207
    PP_VDD_MAIN-0.317

    I know there are more lines I just though I would check in first, Any help is always appreciated


  • #2
    off to a great start with your analysis so far. Anything that is a low voltage line that appears to be power to the CPU will naturally have low resistance--aka "troll line" So your CPU_VAR, PP0v9_SOC_FIXED, PP_CPU_VAR are all in that category. You know it can't be main, and PP1v1_SDRAM does not sound low enough at 0.207. Keep hunting. The common ones would be any rail that is power to NAND, 1v8SDRAM, any power line going through tristar.

    Comment


    • Shrimply Pibbles
      Shrimply Pibbles commented
      Editing a comment
      Thanks @Jessa_the-professa Turns out it was 1v8 I normally check that line too, must of missed it this time. Any Hoo Thanks for the heads up
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