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MacBook A1990 — No Display With Battery Connected

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    #1

    MacBook A1990 — No Display With Battery Connected

    Hi, I have a problem with MACBOOK A1990 - The laptop starts with no image when the battery is connected, but without the battery it starts with an image - however, when using only the power supply, when logging into the system it turns off and resets again.

    Battery replaced with another unit → same problem.

    ISL9239 replaced → no change.

    SMBUS_BATT_SCL / SDA measure ~20-50kΩ to GND with battery disconnected (normal).

    Any ideas or advice would be a huge help!
    Thanks in advance for your time.
    Tags: None
    #2
    What is the voltage to ground of the following with the battery connected?

    SMBUS_3V3_BATT_SCL
    SMBUS_3V3_BATT_SDA

    PPBUS_G3H     with battery?

    Comment

      #3
      I don't know how it happened, but it only works on battery. Maybe it required an SMC reset. After starting it up and entering passwords, it freezes and the touchbar doesn't light up.

      Comment

        #4
        Try a DFU.

        Comment

          #5
          I don't have a second MacBook. Is there an option without additional hardware?

          Comment

            #6
            Post # 2.

            Comment

              #7
              Originally posted by mon2 View Post
              Post # 2.
              PPBUS_G3H - 12V

              SMBUS_3V3_BATT_SCL - 3.3V
              SMBUS_3V3_BATT_SDA               - 3.3V

              Macbook is behaving strangely. When it's hot, it starts up without a picture, but after a while it cools down, the picture appears - but when I try to log in, it hangs.

              Comment

                #8
                Test with an external monitor. The SMBUS voltages are fine - they are not shorted.

                Comment

                  #9
                  Originally posted by mon2 View Post
                  Test with an external monitor. The SMBUS voltages are fine - they are not shorted.
                  External monitor is working. Even though the battery is disconnected, the settings after starting show the information: battery fully charged and service recommended status.

                  Comment

                    #10
                    Backlight fault?

                    Test with a torch / flashlight to the front face of the display. Display is defective? Was the unit dropped? Post pics.

                    Does the caps lock led toggle ok?

                    Comment

                      #11
                      Originally posted by mon2 View Post
                      Backlight fault?

                      Test with a torch / flashlight to the front face of the display. Display is defective? Was the unit dropped? Post pics.

                      Does the caps lock led toggle ok?
                      The image works without the battery, with the battery too, but then the laptop hangs. Apple diagnostics hangs on error code: PFM006

                      Comment

                        #12
                        Run ASD for a deeper dive.

                        https://boards.rossmanngroup.com/thr...nostics.12917/

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