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820-3437 ex water damage SSD not detected

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    #1

    820-3437 ex water damage SSD not detected

    hi everyone,

    i have problem with macbook air 820-3437 ex water damage.
    before it was dead but after some touch on IO board flexible and changing shorted caps i can turn it on. the SSD works fine before but after couple days the question mark folder shows up.

    here are some measurements:

    SSD_RESET_L = 0.55V
    SSD_PWR_EN = 3.25V
    P3V3SSD_VMON = 0V
    PP3V3_S0SW_SSD = 0.99V
    SSD_RESET_CONN_L = 0V

    Already changed U3740 but still the same
    R3742 = 97K
    R3741 = 116K
    R3740 = 85K

    can someone give me a hint?
    Tags: None
    #2
    Re: 820-3437 ex water damage SSD not detected

    Originally posted by kingskie View Post
    hi everyone,

    PP3V3_S0SW_SSD = 0.99V
    Should be 3.3V. Review U8070. In the past I've had corrosion under this IC, either at pin1, or at the ground pin itself (pin 8). Corrosion can sometimes be under the mask, look for a bubbling effect around this IC.

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      #3
      Re: 820-3437 ex water damage SSD not detected

      i change u8070 and get some measurements:

      SSD_RESET_L = 0.9V
      SSD_PWR_EN = 3.25V
      P3V3SSD_VMON = 0.9V
      PP3V3_S0SW_SSD = 3.3V
      SSD_RESET_CONN_L = 0V

      Comment

        #4
        Re: 820-3437 ex water damage SSD not detected

        Originally posted by kingskie View Post
        i change u8070 and get some measurements:

        SSD_RESET_L = 0.9V
        SSD_RESET_CONN_L = 0V
        Should be 3.3V. Pulled high when PLT_RESET_L is asserted via R1639, unless pulled low by the PCH. So check these areas.

        I have had this due to a bad output from the PCH on a 820-3437 Macbook Pro board. I circumvented it by pulling SSD_RESET_L high via a 100 ohm pullup from PP3V3_S0SW_SSD. Basically, when PP3V3_S0SW_SSD is enabled, it pulls the reset line high at the same time. Attached image is from that MBP board.
        Attached Files

        Comment

          #5
          Re: 820-3437 ex water damage SSD not detected

          Originally posted by reformatt View Post
          Should be 3.3V. Pulled high when PLT_RESET_L is asserted via R1639, unless pulled low by the PCH. So check these areas.

          I have had this due to a bad output from the PCH on a 820-3437 Macbook Pro board. I circumvented it by pulling SSD_RESET_L high via a 100 ohm pullup from PP3V3_S0SW_SSD. Basically, when PP3V3_S0SW_SSD is enabled, it pulls the reset line high at the same time. Attached image is from that MBP board.
          many thanks @reformatt, i did circumvent like what you did and it works. does it last long?

          Comment

            #6
            Re: 820-3437 ex water damage SSD not detected

            Still working to this day. Easier than changing the CPU.

            Comment

              #7
              Re: 820-3437 ex water damage SSD not detected

              Originally posted by reformatt View Post
              Still working to this day. Easier than changing the CPU.
              alrite. thanks and best regards

              Comment

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