No ACDRV - Possible faulty capacitor - Pls advise

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  • IamPritesh
    Badcaps Veteran
    • Aug 2017
    • 354
    • India

    #1

    No ACDRV - Possible faulty capacitor - Pls advise

    Please refer to the image . The board came with no charging ..I have replaced the charging IC Bq25A but symptoms are same. There is no schematic or boardview for the same. If the capacitor is faulty, how do I know which value capacitor should I use. Can I use a jumper ?


    Also is ACDRV an output voltage from the Charging IC? I think it should be around 25V

    If any information is missing pls let me know.
    MB : CSL50/CSL52 LA-E791P
    Attached Files
    Last edited by IamPritesh; 03-13-2020, 06:41 AM.
  • piernov
    Super Moderator
    • Jan 2016
    • 4435
    • France

    #2
    Re: No ACDRV - Possible faulty capacitor - Pls advise

    Check second DC-in MOSFET for short between drain/source/gate, and for short to ground.

    ACDRV is indeed a volatge generated by a charge pump inside charger IC and should be around 25V (DC-in voltagr +6V).
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    Comment

    • IamPritesh
      Badcaps Veteran
      • Aug 2017
      • 354
      • India

      #3
      Re: No ACDRV - Possible faulty capacitor - Pls advise

      Actually the ACFET [ MTB04N03] is short between drain and source .
      so which alternative mosfet can I use..? I have the following N channel mosfet in similar package

      MDU2657
      K03B9
      FDMS0312AS
      FDMS7698

      Comment

      • piernov
        Super Moderator
        • Jan 2016
        • 4435
        • France

        #4
        Re: No ACDRV - Possible faulty capacitor - Pls advise

        Anything that has same or higher max Vds (30V), and same or higher current rating Id.
        OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

        Comment

        • IamPritesh
          Badcaps Veteran
          • Aug 2017
          • 354
          • India

          #5
          Re: No ACDRV - Possible faulty capacitor - Pls advise

          Replaced both the mosfet still unable to resolve ACDRV voltage is only 18.5 V

          Comment

          • piernov
            Super Moderator
            • Jan 2016
            • 4435
            • France

            #6
            Re: No ACDRV - Possible faulty capacitor - Pls advise

            Measure exact voltage on both DC-in MOSFETs drain/source/gate.
            Measure resistance to ground after second DC-in MOSFET.
            OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

            Comment

            • mcthr
              Member
              • Aug 2019
              • 24
              • Philippines

              #7
              Re: No ACDRV - Possible faulty capacitor - Pls advise

              Check current sensing resistor if its short to ground

              Comment

              • Sephir0th
                Badcaps Legend
                • Oct 2020
                • 1248
                • Germany

                #8
                Re: No ACDRV - Possible faulty capacitor - Pls advise

                18.5V at ACDRV means there is still a shorted DC-IN Mosfet present. I didn't noticed any other reason so far.
                FairRepair on YouTube

                Comment

                • mcplslg123
                  Badcaps Legend
                  • Jun 2015
                  • 7262
                  • india

                  #9
                  Re: No ACDRV - Possible faulty capacitor - Pls advise

                  Originally posted by Sephir0th
                  18.5V at ACDRV means there is still a shorted DC-IN Mosfet present. I didn't noticed any other reason so far.
                  No doubt about it. Bang on.

                  Comment

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