MACBOOK A1534 820-00244 Logicboard Dead

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  • felix27
    Member
    • May 2023
    • 12
    • Austria

    #1

    MACBOOK A1534 820-00244 Logicboard Dead

    Hello,
    I want to fix a 2016 12 Inch Macbook which has a dead Logic Board.
    USB-C and Battery section seems to work, trackpad clicks, but all cpu Voltages, (VCORE, CPUSA) are 0V, CPU stays cold.
    PPBUS_G3H, 3.3V and 5V Rails seem normal. PM_SLP_S3_L is present but CPU_VR_READY is not.

    Thanks for your help!
  • felix27
    Member
    • May 2023
    • 12
    • Austria

    #2
    ALL_SYS_PWRGD is also present, so i guess, either U7800 or U7100 have some sort of problem. But resistance on the ALL_SYS_PWRGD line is normal, it is not shorted to gnd.

    Comment

    • mon2
      Badcaps Legend
      • Dec 2019
      • 14047
      • Canada

      #3
      What is the current draw? Working at 20v?

      Power cycling or steady voltage & current draw?

      Comment

      • felix27
        Member
        • May 2023
        • 12
        • Austria

        #4
        I do not have an USB ampmeter, but imput voltage is steady at 20v measured at C3101

        Comment

        • felix27
          Member
          • May 2023
          • 12
          • Austria

          #5
          PPVCCIO_S0 is only 0.84V and PM_PCH_PWROK is not present.

          Comment

          • mon2
            Badcaps Legend
            • Dec 2019
            • 14047
            • Canada

            #6
            What is the exact voltage to ground of PPBUS_G3H? (measure @ white fuse F7040)

            Comment

            • felix27
              Member
              • May 2023
              • 12
              • Austria

              #7
              PPBUS G3H is 8.8V

              U3900 gets warm (not extremly hot). Is that normal?

              Could my EFI-Firmware be the Problem?

              Comment

              • PITERPENY
                Badcaps Veteran
                • Jul 2023
                • 455
                • Ukraine

                #8
                as they said on one site “probably a bad CPU)”

                Comment

                • mon2
                  Badcaps Legend
                  • Dec 2019
                  • 14047
                  • Canada

                  #9
                  https://boards.rossmanngroup.com/thr...o-power.60238/

                  Comment

                  • felix27
                    Member
                    • May 2023
                    • 12
                    • Austria

                    #10
                    Thing is, I don't even get vcore and all resistances seem normal. My CPU stays completly cold and CPU VRM isn't even turning on. The PCH doesn't create PM_PCH_PWROK but there is SPI activity on the ROM IC, so the PCH isn't completly dead either.

                    Comment

                    • felix27
                      Member
                      • May 2023
                      • 12
                      • Austria

                      #11
                      I looked at the schematic again and PM_PCH_PWROK isn'r even generated by the PCH. All Voltages that depend on U7100 are gone, even PPVCCSA. Could just U7100 be dead?

                      Comment

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