A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

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  • zeroalpha
    New Member
    • Mar 2022
    • 3
    • Australia
    #1

    A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

    A1706 with some liquid damage. I've cleaned it but PPBUS_G3H will short to ground when its connected to the charger.

    Watch a short clip of whats happening here:

    https://youtu.be/HcegjB4fWVM

    Is there a problem with PPBUS_G3H and what should I look for?
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 14318
      • Canada
      #2
      Re: A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

      1) remove all power.

      2) meter in resistance mode.

      3) measure the resistance to ground of ppbus_g3h. What is the measurement?

      4) remove all power. Remove the output fuse on ppbus_g3h.

      5) measure the resistance to ground on each side of the removed fuse pcb pads. Post each measurement.

      6) power up again - with the fuse removed. What is the voltage to ground of ppbus_g3h at the producer side (ISL) of this power rail ?

      Often, a shorting cap will cause the fault you are observing. The resistance checks will confirm this case.

      Do you have an adjustable power supply?

      Can it be used to dial up a 1v0 output voltage?

        Comment

        • zeroalpha
          New Member
          • Mar 2022
          • 3
          • Australia
          #3
          Re: A1706 Macbook Pro PPBUS_G3H Shorts to ground when charger connected

          3) 2 MΩ

          5) Removed F7000.

          Pin 2 (PPBus_3GH) = 2 MΩ
          Pin 1 (PPVBAT_3GH_CHGR_REG) = O.L

          6)

          Pin 2 (PPBus_3GH) = 1.1v
          Pin 1 (PPVBAT_3GH_CHGR_REG) = 20v

          With the fuse removed PPBus_3GH no longer goes short to ground either

          Yes i have an adjustable power supply

            Comment

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