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Quanta U83 liquid damage no power/no display/shuts off

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    Quanta U83 liquid damage no power/no display/shuts off

    Hi,
    I don't remember the laptop model on top of my head, but the motherboard model is Quanta U83, with discrete graphics.
    After liquid damage, the laptop was turning on for 2 seconds after pressing power button, then shutting off. Cause : no CPU VCore.
    I replaced a 1k resistor and ran a jumper between the buck controller and the resistor and I got VCore back.

    Now, the issue is that when the laptop wasn't turned on for an hour, it turns on fine and shows an image but shuts down after a minute.
    If I try to reboot it immediately, it doesn't show an image and the fan gradually spins up, and it eventually shuts down.
    If I try again, it would shut down after a couple of seconds.
    If I try again another time, the charger IC doesn't turn on the main MOSFET and I get no power.
    If I wait a couple of minute, the charger IC works again. If I wait more, I may have get display for a short time again.
    If I bypass the main MOSFET, same symptoms but I get power everytime obviously.

    Liquid damage was found mainly around charger IC and CPU VCore controller.
    With those symptoms I would say I've got an issue with the EC (KB9010), but there was absolutely no liquid there. I may have an issue with the charger IC, but I guess that if I bypass the main MOSFET, the laptop should still boot.

    What do you think ?
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    #2
    Re: Quanta U83 liquid damage no power/no display/shuts off

    I had similar symptoms on a liquid-damaged laptop. Finally, I found out the cause was a partially-corroded IC that I ignored to replace. I think it is not the EC in your laptop.
    Last edited by caspian; 12-20-2017, 03:34 PM.

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      #3
      Re: Quanta U83 liquid damage no power/no display/shuts off

      It looks like a problem with a fet

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        #4
        Re: Quanta U83 liquid damage no power/no display/shuts off

        This mb is notorious for IO thermal protection. Check that first.

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