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a1989 5V 0,25A

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    a1989 5V 0,25A

    Hello, I am trying to repair my MacBook 820-00850 after small water damage. here are some facts:
    USB-C port burned pin
    liquid damaged pin on power button connector (
    all ports stuck at 5V 0,25A, I can enter DFU (than 20V present and 0A), restore revive not working
    I am missing all SSD power rail and enable signal SSD0_VR_P2V7_EN from U9000 too
    L9080- diode reading is 0,4
    L9080- right after unplugging charger is 0,078 and slowly rising to 0,4 (is it normal?)

    can you advise me please ? thank you

    #2
    Re: a1989 5V 0,25A

    Check diode mode to ground of the LDO rails of all CD3215 chips. Post the readings.

    Meter in diode mode.

    Red lead (yes red) to ground.

    Black meter lead to ldo rail to test.

    Diode readings should be done after enough time is given to discharge the logic board.

    Comment


      #3
      Re: a1989 5V 0,25A

      thank you for your fast replay and time.
      readings: pin 2, 35, 53, 75
      U3100
      0,493
      0,527
      0,515
      0,534
      U3200
      0,497
      0,529
      0,517
      0,535
      UB300
      0,498
      0,530
      0,518
      0,537
      UB400
      0,496
      0,529
      0,518
      0,534

      PPBUS_G3H - 12,29V

      Comment


        #4
        Re: a1989 5V 0,25A

        Diode readings look ok.
        PPBUS_G3H - 12,29V
        From:
        https://www.logi.wiki/index.php?title=PPBus_G3H

        This voltage is low and should be 12v6 after communication with the SMC.

        Measure the voltage readings of:

        I2C_PWR_SDA
        I2C_PWR_SCL


        which are level shifted I2C bus lines used by U7000 for communication.

        Also measure the voltage readings of:

        SMBUS_3V3_BATT_SCL
        SMBUS_3V3_BATT_SDA


        to confirm the status of D6950 (battery ESD transient protection device).

        Meter in DC volts mode (anything 5 volts or higher is ok for these tests).

        Black meter probe to ground (shield is ok).

        Red meter probe to the point to test.

        Post your readings.

        Comment


          #5
          Re: a1989 5V 0,25A

          I2C_PWR_SDA 1,79V
          I2C_PWR_SCL 1,79V

          SMBUS_3V3_BATT_SCL 3,36V
          SMBUS_3V3_BATT_SDA 3,36V

          Battery voltage is 0V
          PPVBAT_G3H_CONN 12,6V after 4seconds 0,2V, after 4seconds 12,6V.. cycling

          and see what happens
          I have checked charger meter and suddenly 20V there and board started to boot. I assembled the whole machine back. I don't know what happened, but at the time of writing this post, MacBook started working... a miracle

          Yesterday I did a reflow of U9000 and U9080 and did not help. I wrote here on Badcaps, did some measurement together and the board started to work now

          Thank you very much for your time and help, If I can donate/support you, let me know please

          Comment


            #6
            Re: a1989 5V 0,25A

            And today the same problem appeard after nearly 10 days of active usage of macbook.
            After few hours of youtube watching I wanted to charge a macbook and nothing happened.
            20V 0A. Restart did not help, and then my battery went to 0% and is dead again
            I am stuck at 5V 0,25A

            SMBUS present, I2C present
            any ideas for help ?
            thank you

            Comment


              #7
              Re: a1989 5V 0,25A

              What is the voltage of PPBUS_G3H ?

              Comment


                #8
                Re: a1989 5V 0,25A

                Ppbus_g3h 12,29v

                Comment


                  #9
                  Re: a1989 5V 0,25A

                  Review the diode readings of each LDO rail of the CD3215 as per post #2.

                  Remove all power. Meter in diode mode to measure.

                  One of the causes of being stuck @ 5V is that a CD3215 has failed.

                  Comment


                    #10
                    Re: a1989 5V 0,25A

                    it is still the same readings :/

                    Comment

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