HP Notebook With Strange Defect Does Not Turn On

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  • dclass-pro
    Senior Member
    • Dec 2022
    • 157
    • Italy
    #1

    HP Notebook With Strange Defect Does Not Turn On

    Hi Guys, I have a HP DAX12AMB6D0 REV.D with a strange defect, that is on the 2nd mosfet on the power supply, the gate voltage does not reach 25V but pulses... if I try to touch some capacitors with my fingers, the voltage on the gate reaches 25V and the notebook turns on.
    I have already tried to change the charging connector, PU1 and PQ20 but I have not obtained any result, the problem still persists.
    Here are the voltages that I find ON PU1:
    Pin 1 - Pulses between 2 and 3v
    Pin 2 - Pulses between 2 and 3v
    Pin 3 - Pulses between 2 and 3v
    Pin 4 - Pulses between 2 and 3v
    Pin 5 - 0v
    Pin 6 - 2.6v
    Pin 7 - 0.07v
    Pin 28 - 19V

    Here is the link to the diagram and the boardview:​
    https://www.badcaps.net/forum/troubl...a-x12a?t=53625

    thanks for the help
    Tags: None
    • dclass-pro
      Senior Member
      • Dec 2022
      • 157
      • Italy
      #2
      Hi guys, has anyone ever had this defect?

        Comment

        • mon2
          Badcaps Legend
          • Dec 2019
          • 13878
          • Canada
          #3
          Which capacitor are you touching? Customer is against this idea as a solution?

          Remove all power. Meter in resistance mode.

          Measure the resistance across the mosfet @ PQ20 (2nd DCin mosfet):

          source / drain
          source / gate
          gate / drain

          Post each measurement. Each measurement should be hundreds of k ohms or higher else could be defective.
          Last edited by mon2; 02-09-2025, 11:37 AM.

            Comment

            • dclass-pro
              Senior Member
              • Dec 2022
              • 157
              • Italy
              #4
              Thanks for the reply, I confirm that they are all very high resistances, I also tried to change the PQ20 mosfet but the result does not change, I also changed the charger... same defect

                Comment

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