T480S NM-B471 No start - only after removing all batteries

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  • exe557
    Member
    • Jan 2021
    • 24
    • Germany
    #1

    T480S NM-B471 No start - only after removing all batteries

    Maybe somebody has an idea.
    Got this T480s in this conditions.

    It will power up, if internal battery and CMOS battery are disconnected.
    Plugin in a power supply will make the unit start.
    There is no reaction to the power button at all. The button board has been replaced. Same behaviour.

    Assumed a bad EC flash and reflashed a clean update from a BIOS update via Vertyanov. Bios flash is also fine.

    The PWRSWITCH line has 3.3V level which gets pulled down when the button is pressed.
    Tags: None
    • exe557
      Member
      • Jan 2021
      • 24
      • Germany
      #2
      Re: T480S NM-B471 No start - only after removing all batteries

      Finally solved this issue.
      PWRSW is going to EC and from there it is output on another pin as PWRSW_EC. This was not coming out of the EC. Replacing EC is difficult because of glue. Used a jumper wire between PWRSW and PWRSW_EC. Power button works as expected now.

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