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Macbook Air A1466 2015 logicboard 820-00165 turns on BUT no screen and chieme (sound)

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    Macbook Air A1466 2015 logicboard 820-00165 turns on BUT no screen and chieme (sound)

    Hello,

    I would appriciate very much if someone is more agile than me to solve my current issue with a logicboard of MB AIR 2015 13", #820-00165

    The board is powering up, the fan starts spinning, all voltages are present, green/orange light is on but I don't hear the chieme, the screen is not showing any signs and the external screen isn't working either.

    There was a little liquied damage on the reset chip U5110 which I have cleaned. I took it also off and cleaned it underneath. Also some damaged copper trace I fixed too. The cap C5120 I replaced as well. One side had corrosion. But all this didn't help! There is no obvious sign of any other damage caused by the liquid.

    My test setup looks as follows: logicboard, audio/power PCB, power adapter, battery, ssd with installed OSX, external monitor on display port.

    When the board starts I noticed the fan stop spinning shortly after a few seconds then it starts running again for always. If I only have battery connected to the board the fan runs about 10s and stops for about 2s then restarts for 10s again and again. If I connected a working board the fan never stops spinning with or without power adapter.

    Does anyone has an idea in which direction I could look at? The issue is really hard to detect. I hope SMC or GPU are not causing the problem.

    I am very thankful for anyone who can help!!

    THX
    Mario

    #2
    Re: Macbook Air A1466 2015 logicboard 820-00165 turns on BUT no screen and chieme (so

    Mario,

    Can you post voltages of the different rails like they do in this thread (https://www.badcaps.net/forum/showth...ighlight=U5110)? That will help to narrow it down.

    Thanks,

    Joe
    Last edited by aazjo; 07-12-2020, 01:44 PM. Reason: URL was not parsed correctly.

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      #3
      Re: Macbook Air A1466 2015 logicboard 820-00165 turns on BUT no screen and chieme (so

      Could be a bios issue.

      Comment


        #4
        Re: Macbook Air A1466 2015 logicboard 820-00165 turns on BUT no screen and chieme (so

        Any history apart from liquid damage? CPU VCore present? PLT_RESET_L?
        To diagnose the board you only need a Magsafe, DC-in board (FFC is not required to be connected), fan and obviously main logic board.

        If there was liquid damage on U5110 there may be damage somewhere else… do a thorough visual inspection near SMC, SPI ROM, J6100…
        OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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          #5
          Re: Macbook Air A1466 2015 logicboard 820-00165 turns on BUT no screen and chieme (so

          Voltage on pin 5 and 8 of U5110 correct?

          Any usb activity?

          I've had a few of these - a nightmare tbh. Start off by a thorough U/S clean. Could be anything from bios, corrosion around smc/U6100 tracks/U1950 and there were a couple of mysteries I never solved! I usually leave these to the side and come back to them from time to time if I'm bored.
          Last edited by luckydip; 07-15-2020, 09:28 AM.

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