Macbook Pro 2018 A1989 - Only 5V - Had PPBUS_G3H, not anymore

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  • BMCappelletti
    Senior Member
    • Nov 2021
    • 171
    • Brasil
    #1

    Macbook Pro 2018 A1989 - Only 5V - Had PPBUS_G3H, not anymore

    Hi everyone.
    Macbook Pro 2018 A1989, board 820-00850.
    Only 5V on the meter, and around 250 mAmps drawn. Lots of dust on the sides, as usual. Cap CD308. right over CD3215 (UB300) was shorted. I did have PPBUS_G3H at 12.3V. measured on CC851, if I am not mistaken.
    Replaced CB308 with a cap from another board, with same specs. Now I don't have a short on it anymore, but neither PPBUS_G3H.
    When connecting the meter to the USB-C ports it keeps restarting, except on front port on the other side. And CD3215 close to it (U3200) gets hotter than usual. F3000 is the fuse with 5V on it, meaning (I guess) that USB-C port is connected to it. So, U3100.
    How should I proceed now? Is it a confirmation that CD3215 (U3200) is the bad guy here and needs to be replaced?
    Any help is much appreciated.
    Thank you!
    Last edited by BMCappelletti; 12-05-2025, 04:00 PM.
    Tags: None
    • BMCappelletti
      Senior Member
      • Nov 2021
      • 171
      • Brasil
      #2
      Well, progress.
      There was a cap (C3108) cracked, besides U3100. Now I have PPBUS back.
      Still with 5V, but all but one USB-C are stable. When connected to the back USB-C port, on left side, meter loops. On the other 3 portas it is 5V with 250mAh drawn.

        Comment

        • BMCappelletti
          Senior Member
          • Nov 2021
          • 171
          • Brasil
          #3
          More information.
          I do have PP1V1_UPC_XA_LDO_BMC and PP1V1_UPC_XB_LDO_BMC.
          The other side of the board, with PP1V1_UPC_TA_LDO_BMC and PP1V1_UPC_TB_LDO_BMC, is cycling the meter. One of the ports (back one) right away when I connect it. The other (front port) every like 10 seconds. So no 1.1V in those LDO lines.

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14996
              • Canada
              #4
              The 1v1 is a critical one to run the BMC circuits used by the CCx pins. Test if there is a short on this rail. Part may be defective.

                Comment

                • BMCappelletti
                  Senior Member
                  • Nov 2021
                  • 171
                  • Brasil
                  #5
                  Originally posted by mon2
                  The 1v1 is a critical one to run the BMC circuits used by the CCx pins. Test if there is a short on this rail. Part may be defective.
                  No shorts. Tested directly on the capacitors where the signal connects from the CD3215 chip.

                    Comment

                    • BMCappelletti
                      Senior Member
                      • Nov 2021
                      • 171
                      • Brasil
                      #6
                      Damn those CD3215 are expensive. 1/6 of what I paid for the whole Macbook. And it has the underfil to deal with.

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