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820-00138-A Q7706 PPBUS_G3H Short

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    820-00138-A Q7706 PPBUS_G3H Short

    Hi., I am working on a Apple Macbook Pro Retina A1398 15.6" 820-00138-A., Not turning on (Dead). There was liquid spill near U7200 & slight green stuff near the SMC. Replaced the U7200., Now I get the green light, but there is a severe short on PPBUS_G3H, almost 0 ohms. Just to narrow down the trouble shooting & verify where the short was, I removed the 2 fuses F7140 & F7141. After removing the fuse I surely get back PPBUS_G3H 12.8V on L7130, now atleast I know that the short is across the fuse. Has anyone found the short on this logic board after the fuses or can anyone inform me what further components should I check. The boardview which I have is not of the exact match or anyone has a board view for this model. Thanks
    Last edited by mferna14; 06-27-2020, 04:59 PM.

    #2
    Re: 820-00138-A Q7706 PPBUS_G3H Short

    U can search on google for the but doardview with the board number to download boardview

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      #3
      Re: 820-00138-A Q7706 PPBUS_G3H Short

      Please view the photos, all the mark caps have reading of nearly 0 Ohms across them.. Do you think the CPU is shorting the caps. Any ideas will be appreciated... Thanks
      Attached Files

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        #4
        Re: 820-00138-A Q7706 PPBUS_G3H Short

        What's the exact resistance to ground? ("almost 0 ohms" is not precise enough)
        OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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          #5
          Re: 820-00138-A Q7706 PPBUS_G3H Short

          Seriously the meter reading across all the caps you see in marked on the photos shows 0 ohms., something is completely short to ground, either its the CPU/GPU or one of the caps, which I am doubtful now since the caps on the CPU SR1ZX too when I take a meter reading it almost 0 ohms. Physically I do not see anything burnt or bursted. Do you think its the CPU/GPU since the tiny caps on it too are show 0 ohms???

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            #6
            Re: 820-00138-A Q7706 PPBUS_G3H Short

            Just received one of these today with dead short across PPBUS_G3H. No prizes for guessing where the source of that one was.

            U7310 was short, and so was the CPU; confirmed with voltage injection and thermal camera. So whenever I see this, I check the driver and sure enough, there was the smallest amount of liquid damage to the sense pins of U7200. I really hate how these things self destruct with something like this.
            Attached Files
            Last edited by reformatt; 05-20-2022, 01:50 AM.

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