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IDEAPAD NM-D031 MB with 10 second boot cycle

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    #1

    IDEAPAD NM-D031 MB with 10 second boot cycle

    Hi got a recent liquid damaged Ideapad 3 with tenth gen i5 has the DO31 MB. I've done some work but its stumping me.

    mb has been alcohol cleaned and button board replaced where most of the liquid went...( a little on keyboard flax connector but cleaned up well.

    Main Problem:-

    The laptop starts and switches off in repeating 10 second cycles.?
    No fan starting.

    Their are no obvious signs of damage and pl's and caps have been checked for direct shorts?

    Battery charges fine.

    I've measured resistance and voltage on pl,s before and during start-up and:-

    3v PL1101 is 360 ohm and around 3.2v
    5v PL1601 is 361 ohm and 4.2v.
    1.8v PL9800 is 304 ohm and 1.2v
    vcc in PL3401 and pl 3400 166ohm and 0v
    vcc aux pl9801 is 370ohm and 0v
    VDDQ PL9802 is 196ohm and 0v
    CHG PL100 is 573ohm and 0.2v battery disconnected

    I,m thinking the problem lies with the 5v rail and the 1.8v, being pulled down but after checking the caps (caps seem good) I've run out of ideas..

    any help greatly appreciated

    Attached Files
    File Type: rar NM-D031.rar (2.92 MB, 0 views)
    Tags: None
    #2
    Re: IDEAPAD NM-D031 MB with 10 second boot cycle

    Update:

    I've removed jumper pj406 5v alw...and the supply voltage is at 5.1v..
    Something after the power supply jumper is pulling the voltage down.

    I've attached board view and schematic for those with quicker skills than myself

    Resistance of the remaining 5v circuit (excluding 5vps) is 496ohm.

    I'm thinking of voltage injection, I've identified several regulators that the 5v goas to as well as the usb ports. but would something dropping 0.8v heat up?

    MOD Edit: Link to schematic and boardview --->
    https://www.badcaps.net/forum/showth...55#post1131955
    Last edited by Vesko356; 08-02-2023, 03:32 AM. Reason: Attached schematic and BV removed and replaced with link.

    Comment

      #3
      Re: IDEAPAD NM-D031 MB with 10 second boot cycle

      Originally posted by coltron View Post

      I've attached board view and schematic for those with quicker skills than myself
      Do not attach laptop schematic and/or BV in this section please!

      Schematic Requests ONLY!
      https://www.badcaps.net/forum/forumdisplay.php?f=41

      Reminder: rules and organization of this section
      https://www.badcaps.net/forum/showthread.php?t=117483
      If you request/offer BIOS/schematics/boardviews, please post in the appropriate subsection, and you can link to it in the troubleshooting topic.
      .
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      Comment

        #4
        Re: IDEAPAD NM-D031 MB with 10 second boot cycle

        thanks for making me aware

        Comment

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