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MacBook Pro A2338 won't start

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    MacBook Pro A2338 won't start

    I am trying to repair my Macbook A2338 820-02020.

    I was able to narrow down the cause to some extent, but I don't have any conclusive evidence to identify the cause, so I would appreciate any advice.

    Here is what I did:

    When I plugged in the power, the voltage rose to 20V, but there was no change after that, and the CPU did not appear to be working.

    I tried to revive it in DFU mode with APPLE Configurator, but it stopped with an error halfway through.

    It probably failed when starting the CPU to write.

    I measured the power supply of the board, and found that
    PPDCIN_USBC_AON was 20V, but
    PPBUS_AON was only 12V. The normal voltage is 12.6-13.1V, so it is very low.

    According to repair.wiki, if it is 12.28-12.35V, it is a problem with the communication between the SOC and PMICs,
    but the voltage is lower than this range.

    The other power rails seem fine.
    PP3V8_AON 3.8V
    PP3V3_S2 3.28V
    PP5V_S2 5.17V
    PP3V_S2_UPC 3.29V
    PP1V25_S2 1.22V

    #2
    Confirm the voltage rails for the NAND flash devices:

    PP2V5_AWAKE_NAND

    Comment


      #3
      Thank you for your advice.
      I measured PP2V5_AWAKE_NAND.
      It was 2.53V.

      Comment

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