Macbook Pro A2251 Stuck on 5v

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  • ronelex
    Senior Member
    • Oct 2016
    • 195
    • Philippines
    #1

    Macbook Pro A2251 Stuck on 5v

    Hi everyone, I have this unit A2251 820-01949.
    I receive this unit with a shorted PP3V3_G3H and found the culprit C8161 shorted and I remove it but the unit still stuck at 5v 0.04A
    This are the readings I got on the unit

    PPBUS_G3H -12.33v
    PP1V8_SLPS2R -0v
    PP3V3_G3H_PMU_VDDMAIN/PP3V3_G3H - 0v
    P1V8G3S_EN from u7800 - 0v

    U3100_W
    PPHV_INT_G3H_W - 5v
    PP1.5_UPC_LDO_CORE_W - 1.5
    PP3V3_UPC_W_LDO - 3.3V
    PP3V3_G3H_RTC - 3.3V

    U3100_R
    PP1.5_UPC_LDO_CORE_R - 1.5
    PP3V3_UPC_R_LDO - 3.3
    PP3V3_G3H_RTC - 3.3

    U3100_X
    PP1.5_UPC_LDO_CORE_X - 1.5
    PP3V3_UPC_X_LDO - 3.3
    PP3V3_G3H_RTC - 3.3

    U3100_T
    PP1.5_UPC_LDO_CORE_T - 1.5
    PP3V3_UPC_T_LDO - 3.3
    PP3V3_G3H_RTC - 3.3​
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 14713
      • Canada
      #2
      Remove all power. Measure the resistance to ground on the power rail that is at 0 volts. Repeat for the enable line for that rail that is also at 0 volts.

        Comment

        • ronelex
          Senior Member
          • Oct 2016
          • 195
          • Philippines
          #3
          PP1V8_SLPS2R -3.7k ohms
          PP3V3_G3H_PMU_VDDMAIN/PP3V3_G3H - 2.4 mega ohms
          P1V8G3S_EN from u7800 - 40k ohms
          I got this low ohms reading on
          L8100 /PP1V1_S3_REG_R - 2.5ohms
          I dont know if this is normal because I dont have any identical board onhand

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14713
              • Canada
              #4
              Post the diode mode readings of L8100. Remove all power. Meter in diode mode.

              red meter probe, yes red to ground.
              black meter probe to L8100.

              follow this thread - may be the same fault:

              https://boards.rossmanngroup.com/thr...6-0-35a.62664/

              post your updates.

                Comment

                • ronelex
                  Senior Member
                  • Oct 2016
                  • 195
                  • Philippines
                  #5
                  ok thanks for the guide sir, I will update after I check it again

                    Comment

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