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820-00875 PPBUS_G3H boosting after liquid damage

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  • 820-00875 PPBUS_G3H boosting after liquid damage

    Hi, I have a 00875 thats had liquid damage over the U7650 side of the board.

    After going through the UC, the laptop started from the battery and got into the OS but I walked away and came back to it turned off. Not sure if the battery is drained or something else.
    I don't have a spare battery to test with.

    20.4v going into the board from the genuine charger.
    PPBUS_G3H is boosting to 12.93v and then dropping to 3.4v repeatedly
    s5_pwrgd is boosting to 5.1v then drops to 3.2v and then drops to 0v.. it then starts over again.

    I get a fan twitch and the CPU is getting warm

    Apologies if I should have given some basic info that I've missed in this initial post.

    Any help would be appreciated

  • #2
    Try to start in SMC bypass mode first.


    • #3
      Hi 2informaticos.. holding down the power for smc bypass doesn't seem to do anything different


      • #4
        I lied.. it just did smc bypass and started


        • #5
          Start then in SMC bypass mode and check all power sensors output, pages 43-45.
          Be sure first to have correct AVREF_SMC voltage.


          • #6
            It turns itself off after a few seconds. Gets into the OS but thats about it before the power cuts off


            • #7
              When it cuts power, the DCIN drops to 5.2v 0.02a


              • #8
                SMC bypass doesnt seem to work either now. Fan spins full for about 2 seconds but nothing more and no screen.


                • #9
                  Try UC again.
                  You can check one power sensor every time the machine turns on.
                  2s should be enough for one reading; no need to login to OSX.


                  • #10
                    AVREF_SMC is 2.98v


                    • #11
                      so its all the vsense isense outputs I'm checking right?


                      • #12
                        Yes, check all them.
                        Now is strange if doesn't start on SMC bypass too.
                        But check them, maybe help to make an idea.


                        • #13
                          I'm struggling to be able to accurately check them.. They are all on the opposite side of the board. I need about 6 pairs of hands


                          • #14
                            C5409 SMC_CPU_HI_ISENSE = 30MV

                            C5680 SMC_CPU_VSENSE = 0.5-0.9 BOOSTING

                            C5605 SMC_CPU_ISENSE = 0V

                            C5615 SMC_GT_ISENSE = 135MV

                            C5682 SMC_GT_VSENSE = 0MV

                            C5691 SMC_SA_IMON_ISENSE = 359MV

                            C5631 SMC_SA_ISENSE = 0MV

                            C5523 SNC_3V3S5_ISENSE = 0.5V

                            C5518 SMC_3V3SSD_ISENSE = 0MV

                            C5690 - SMC_CPU_IMON_ISENSE = 0V

                            C5469 SMC_TPAD_ISENSE = 0V

                            C5508 SMC_1V2S3_ISENSE = 0V

                            R5489 SMC_PBUS_VSENSE = 2.1V

                            C5489 SMC_PBUS_VSENSE = 2.1V

                            C5438 SMC_BMON_ISENSE = 0V

                            C5533 SMC_3V3WLS_ISENSE 0V

                            C5459 SMC_LCDBKLT_ISENSE = 0V

                            C5528 SMC_3V3LCD_ISENSE = 0V

                            Hopefully theres something here that looks odd


                            • #15
                              Still not working on SMC bypass?


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