Announcement

Collapse
No announcement yet.

Macbook Pro 2019 16" A2141 820-01700 stuk in DFU mode

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    Macbook Pro 2019 16" A2141 820-01700 stuk in DFU mode

    Hi all,

    I am trying to fix a T2 Macbook A2141 820-01700 board that's stuck in DFU mode.

    The SSDs have correct voltages

    PP2V5_NAND_SSD0 = 2.5V
    PP2V5_NAND_SSD1 = 2.5V

    PP0V9_SSD0 and PP0V9_SSD 1 = 0.9V

    PP1V8_SSD0 and PP1V8_SSD1 = 1.8V

    I can force the laptop to DFU mode using the SOC_FORCE_DFU using SWK003. Apple Configurator 2 tries to restore the Mac but it fails back to RECOVERY.

    Looking at the diagram here - https://repair.wiki/w/Apple_T2_platform Step 6, it says the problem could be loading from SSD, it will fall back to recovery.


    I don't have any short any NAND chips, is there any way I can check what could be wrong?

    Thanks
    Tags: None
    #2
    What is the voltage to ground of PPBUS_G3H?

    Is the board at 20v on the USB C meter? What is the current draw?

    What is the voltage to ground of ALL_SYS_PWRGD?

    Comment

      #3
      Originally posted by mon2 View Post
      What is the voltage to ground of PPBUS_G3H?

      Is the board at 20v on the USB C meter? What is the current draw?

      What is the voltage to ground of ALL_SYS_PWRGD?
      PPBUS_G3H = 12.60v

      USB-C meter - 20.26v 0.06-0.07a

      ALL_SYS_PWRGD = 0v

      Comment

        #4
        Do you have a known good and charged battery attached to this unit? Are you using at least a 96W USB-C charger with the unit?

        ALL_SYS_PWRGD = 0v
        This signal indicates that at least one power rail is absent onboard. Suggest to test the voltage to ground of each and every inductor. If you are not comfortable with this, consider to remove all power / disconnect the battery and test the resistance to ground of each inductor onboard. Checking for lower than normal resistance values which may indicate a shorted part is on that power rail.

        Comment

          #5
          Originally posted by mon2 View Post
          Do you have a known good and charged battery attached to this unit? Are you using at least a 96W USB-C charger with the unit?



          This signal indicates that at least one power rail is absent onboard. Suggest to test the voltage to ground of each and every inductor. If you are not comfortable with this, consider to remove all power / disconnect the battery and test the resistance to ground of each inductor onboard. Checking for lower than normal resistance values which may indicate a shorted part is on that power rail.
          Yes, I am have tried with known good battery and using a 140W USB-C charger that works fine with same model board.

          I tried checking voltages as on this https://repair.wiki/w/Apple_T2_platf...ence_ver_5.png and PCH_RTC_RESET_L is High at 3.0v (expect it to be low) and PMU_CLK32K_PCH is 0.8v
          As per the oducment PCH_RTC_RESET_L should go to Low when BridgeOS boots. That seems to be my problem.

          I will try to check the inductors too.

          Comment

            #6
            PCH_RTC_RESET_L is High at 3.0v (expect it to be low)
            The _L suffix denotes this signal to be active low type. So if LOW, the part is in reset state. When released to HIGH, the part is now in run state. You will need an oscilloscope or logic analyzer to monitor this line if there is a concern.

            Comment

            Previous template Next
            Working...
            X