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MacBook Pro A2289 (820-01987-A) No boot or Display, but boots to DFU and shows status bar only

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    #1

    MacBook Pro A2289 (820-01987-A) No boot or Display, but boots to DFU and shows status bar only

    Hi everyone.

    Recently got MacBook Pro A2289 with interesting behavior. Pristine condition, no water damage, no visual issues whatsoever. It has no image, no Caps Lock, no life except the fan is spinning. But it is able to connect to DFU mode and recognized by another MacBook. I tried to revive but the process ends when the MacBook usually should show an Apple logo with a progress bar and giving me error AMRestoreErrorDomain error 9. I don't have CPU Vcore.
    Now I can't able to connect to DFU mode either.

    On the USB meter I got 20V/0.9A power draw, and keep looping. The fan is spinning. No image (I checked with a bright flash light), no sound, no CapsLock activity. Found similar case on repair wiki: https://old.repair.wiki/w/A2289_2020_13%22_MacBook_Pro

    PP0v95_S0_CPUVCCIO_REG_R is present 0.9V.

    What should I check next? is there any power sequence for this model?

    Looking forward for your help.
    Tags: None
    #2
    Check resistance to ground on PP2v5_NAND_SSD_0. No power during resistance checks.

    Comment

      #3
      What is the voltage to ground of ppbus_g3h? Stable?

      Be sure your usb cable is of quality. We use a 40G rated one from Amazon. Short as possible.

      From Rossmann forum on this model :

      So machine is in some kind of power cycle.
      No DFU possible, if AWAKE and SLPS2R voltages are not stable.

      Comment

        #4
        Hi mon2
        Thanks for the replay.

        I have checked PP2v5_NAND_SSD0 it's 200k.
        ppbus_g3h is 12.62V while it's turn on.
        When it try to boot and draws 1.12A at that time ppbus_g3h drop down to 10.24V.

        I am using apple original type-c cable. Still I'll order one from amazon.

        Comment

          #5
          What is the power rating of your external power adapter? Suggest a 100W power delivery unit or higher for testing. Be sure that the USB Type C cable is an active cable with an e-marker else the passive USB Type C cables will not support the higher current. TBH - not sure if the Apple original cable is active Type C design or not. However, 20V @ 1.12A is ~22W so not so demanding but be sure your power adapter is original or of quality. When I was in Asia last October - saw many offering 140W and higher bricks with GAN3 semiconductors making them smaller than the last generation of adapters. Many were not CSA / cUL listed, etc. so would not trust those.

          Comment

            #6
            Hi mon2
            Thanks for your support.

            Luckily I got another Mac and I swapped the board and it's working.
            Now I need to figure out what is causing problem to not booting into original mac assembly.

            Appreciated for you help.
            Cheers!!

            Comment

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