yoga9 3v3 5v fluctuating

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  • koby058
    Badcaps Veteran
    • Jan 2017
    • 378
    • israel
    #1

    yoga9 3v3 5v fluctuating

    Hi

    board model: NM-D992

    type c remains on 5v. when i connect it the 3.3VALW and 5VALW fluctuating. can someone please help understand why?
    main power rail voltage 13v

    till now i have tried:
    measured all coils resistance looks ok
    replaced RT6585CGQW to a brand new one
    replaced all mosfets for 3.3v regulator and the dual mosfet for 5v regulator
    happen both on DC power and on battery
    issue remains

    video

    schematic attached
    Attached Files
    Last edited by koby058; Yesterday, 09:23 AM.
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 14177
      • Canada
      #2
      Remove all power. Meter in resistance mode. Measure the resistance to ground of the rails that are fluctuating.

      What are the measurements for each?

        Comment

        • koby058
          Badcaps Veteran
          • Jan 2017
          • 378
          • israel
          #3
          Hi and thanks for trying to help

          on the 3.3v coil 5.87K
          on the 5v coil 5.78K

            Comment

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