MacBook Pro A1398 - 820-3787-A

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  • uas66
    New Member
    • Oct 2016
    • 4
    • Netherlands

    #1

    MacBook Pro A1398 - 820-3787-A

    Hi all, my keyboard lighting stopped working. I opened the casing to clean the fans, and after that the keyboard lighting stopped working. I did not unscrew something. I see the bars going up and down when pressing on the keyboard lighting keys. Already did SMC, PRAM reset.

    Did I maybe short something on the motherboard?
  • piernov
    Super Moderator
    • Jan 2016
    • 4435
    • France

    #2
    Re: MacBook Pro A1398 - 820-3787-A

    Reseat keyboard backlight connector.
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    Comment

    • uas66
      New Member
      • Oct 2016
      • 4
      • Netherlands

      #3
      Re: MacBook Pro A1398 - 820-3787-A

      Thanks, I already did that. I checked R7723 & R774 and they measure both 10ohm. All pins on J4915 are connected.

      Comment

      • Stephen
        Meow Meow MEOW!
        • Apr 2020
        • 667
        • United States

        #4
        Re: MacBook Pro A1398 - 820-3787-A

        Backlight connector could be faulty. Do you have a microscope to see if its bent or ripped? If it is, you will have to replace the backlight film (easy fix but will require you removing the logic board again.
        sigpic
        MEOWING IN THE IMPOSSIBLE UNIVERSE!

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        • uas66
          New Member
          • Oct 2016
          • 4
          • Netherlands

          #5
          Re: MacBook Pro A1398 - 820-3787-A

          Found the problem. R7783 should be 0 ohm but was about 10k ohm. Replaced with a new one and backlight is working again.

          Does someone know how it is possible that the ressistor go bad?

          Comment

          • Stephen
            Meow Meow MEOW!
            • Apr 2020
            • 667
            • United States

            #6
            Re: MacBook Pro A1398 - 820-3787-A

            Most likely the Resistor may have came off the board partially etc. I have seen an instance where a Resistor was not fully seated and the Audio was out on one of our Boards. We seated the Resistor and solved the issue. I would assume this was the cause, you could have most likely bumped into that Resistor and caused it to lift.
            sigpic
            MEOWING IN THE IMPOSSIBLE UNIVERSE!

            Comment

            • piernov
              Super Moderator
              • Jan 2016
              • 4435
              • France

              #7
              Re: MacBook Pro A1398 - 820-3787-A

              Connector manipulated while there was still power inside the board
              OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

              Comment

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