A1286 No backlight

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  • m4a2t0t
    Badcaps Veteran
    • Mar 2013
    • 276
    • USA
    #1

    A1286 No backlight

    I have a Macbook Pro A1286 with a core i5 and it has no backlight after reballing the GPU.

    The laptop would not display any high resolution content. After clicking on the username the laptop would start loading and then display a grey screen. It would not load recovery, internet recovery or any utility.

    The laptop will now login and displays content fine but it has no backlight.

    Any suggestions on what to look at first? Anyone have schematics or board viewer?

    I've tried re-plugging all the cables, SMC reset and tried the brightness buttons. Anything I might be overlooking?

    Thanks

    EDIT: FOund board viewer https://www.badcaps.net/forum/showthread.php?t=44413 . Will check Backlight filter.
    Attached Files
    Last edited by m4a2t0t; 01-20-2018, 08:01 PM. Reason: Found board viewer
    Tags: None
    • audiomodder
      Senior Member
      • Dec 2017
      • 54
      • USA
      #2
      Re: A1286 No backlight

      Search 820-2915-A schems and boardview in an internet search. you will come up with stuff.
      Did you seriously attempt a GPU reball without even the schematic? Wow....gutsy.
      Once you get the schem, check out the backlight driver circuit and look at the EN pin. Also, the CLK and DATA (coming from the GPU) lines with 100k pullups to the LVDS are important and will keep your internal display from working if they are shorted or missing.

      There is also a small backlight fuse which is always worth checking. But get on those schematics first.

        Comment

        • alihomee
          Badcaps Legend
          • Dec 2012
          • 1570
          • malaysia
          #3
          Re: A1286 No backlight

          u can find fuse and light ic near the fan connector

            Comment

            • m4a2t0t
              Badcaps Veteran
              • Mar 2013
              • 276
              • USA
              #4
              Re: A1286 No backlight

              Thanks. The fuse is open. Guess I should start at the beginning of the circuit instead of the end.

                Comment

                • audiomodder
                  Senior Member
                  • Dec 2017
                  • 54
                  • USA
                  #5
                  Re: A1286 No backlight

                  yep, check the EN stuff first, then the IC output, then both sides of fuse. If all is OK only THEN replace the fuse.

                    Comment

                    • tblam
                      New Member
                      • Nov 2019
                      • 2
                      • Canada
                      #6
                      Re: A1286 No backlight

                      Hello! (I am new to forums so I hope I'm not doing anything wrong writting on someone else's post!)

                      I also have this board, no GPU reballed just the original thing. Fuse is 12.53V on each side and I have 3.3V on BKLT_RST but 0V on BKLT_EN. So I guess I have to change IC U9600 but where can I see if there is power going to it first? I don't want to unsolder that kind of thing for the first time and find out later that it was not the problem xD

                      Thanks for your help!

                        Comment

                        • piernov
                          Super Moderator
                          • Jan 2016
                          • 4435
                          • France
                          #7
                          Re: A1286 No backlight

                          820-2915 = dead GPU.
                          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                            Comment

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