Zephyrus Duo 15 No Display or Power

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  • Brown sugar builds
    Member
    • Jan 2024
    • 11
    • United States

    #1

    Zephyrus Duo 15 No Display or Power

    I got this laptop as a trade and from what I can find, there's no power on the motherboard other than the power coming from the charger. I can find 20v by the charger but no other power rails anywhere else. Is this a bad charging ic or what would cause this. I've used a thermal imager and there's nothing hot.
  • mon2
    Badcaps Legend
    • Dec 2019
    • 13835
    • Canada

    #2
    1) Review the charger circuit sticky above by piernov - great reading on how charger circuits function.

    2) Be sure that the power adapter is suitable for this laptop.

    3) Trace the DCin power connector to locate the DCin mosfets. What are their topside markings? The mosfets will be black in color with 8 pins (4 on each side). Following these 2 * DCin mosfets will be a charger IC that is responsible to enable / disable these mosfets. The gate pin # 4 of the mosfets will often be controlled by the charger IC. Share quality pics and/or details of the topside markings of the charger IC.

    4) Remove all power -> meter in resistance mode -> measure the resistance to ground of these DCin mosfets. Checking for a low resistance which may confirm that there is a shorted component in the power path of these mosfets -> causing the power supply to be shut off.

    5) If available, share a link to the schematic (do not post it here) -> post the schematic in the dedicated schematic forum.

    Comment

    • Brown sugar builds
      Member
      • Jan 2024
      • 11
      • United States

      #3
      Originally posted by mon2
      1) Review the charger circuit sticky above by piernov - great reading on how charger circuits function.

      2) Be sure that the power adapter is suitable for this laptop.

      3) Trace the DCin power connector to locate the DCin mosfets. What are their topside markings? The mosfets will be black in color with 8 pins (4 on each side). Following these 2 * DCin mosfets will be a charger IC that is responsible to enable / disable these mosfets. The gate pin # 4 of the mosfets will often be controlled by the charger IC. Share quality pics and/or details of the topside markings of the charger IC.

      4) Remove all power -> meter in resistance mode -> measure the resistance to ground of these DCin mosfets. Checking for a low resistance which may confirm that there is a shorted component in the power path of these mosfets -> causing the power supply to be shut off.

      5) If available, share a link to the schematic (do not post it here) -> post the schematic in the dedicated schematic forum.
      After looking it up, I believe the ic chip markings are IT8299E120A
      2021-CXA
      S18CGA
      I'll continue to do #4 to see if I can find any shorts. I did get a short to ground probing I think it would be pin 5 of one of the mosfets

      Comment

      • Brown sugar builds
        Member
        • Jan 2024
        • 11
        • United States

        #4
        Yeah so far more than one I've gotten 0 ohm shorts on pins 4 and 5

        Comment

        • mon2
          Badcaps Legend
          • Dec 2019
          • 13835
          • Canada

          #5
          IT8299E120A = SIO controller and used for the keyboard + real time clock and few other functions. This is not your charger IC. Review around for a leadless square IC which should be smaller in size than this one. Perhaps is on the opposite side of the mosfets (ie. top / bottom side of the circuit board).

          Could be with a 'BQ' markings = Texas Instruments or another brand. Being Asus, chances are slim that there is a schematic for your logic board but we may be able to figure it out without one.

          What are the topside markings of the mosfets near the DCin power connector? Using Google, we should be able to figure out if they are N-channel or P-channel type of mosfets.

          Comment

          • Brown sugar builds
            Member
            • Jan 2024
            • 11
            • United States

            #6
            Originally posted by mon2
            IT8299E120A = SIO controller and used for the keyboard + real time clock and few other functions. This is not your charger IC. Review around for a leadless square IC which should be smaller in size than this one. Perhaps is on the opposite side of the mosfets (ie. top / bottom side of the circuit board).

            Could be with a 'BQ' markings = Texas Instruments or another brand. Being Asus, chances are slim that there is a schematic for your logic board but we may be able to figure it out without one.

            What are the topside markings of the mosfets near the DCin power connector? Using Google, we should be able to figure out if they are N-channel or P-channel type of mosfets.
            Ahh ok. Then the mosfets look something like
            64 UUB
            6W0K04 or 6W0KD4

            Comment

            • Brown sugar builds
              Member
              • Jan 2024
              • 11
              • United States

              #7
              And would the ISL9238BH be what you're looking for the IC

              Comment

              • mon2
                Badcaps Legend
                • Dec 2019
                • 13835
                • Canada

                #8
                ISL9238BH - yes This is the charger IC for your logic board. No hits on the mosfets. Can you post a pic of this region?

                They should look something like the attached:

                Click image for larger version

Name:	N-channel.png
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ID:	3214821

                Comment

                • Brown sugar builds
                  Member
                  • Jan 2024
                  • 11
                  • United States

                  #9
                  Alright here's a few pictures. Click image for larger version

Name:	20240211_183801.jpg
Views:	117
Size:	2.40 MB
ID:	3214840
                  Attached Files

                  Comment

                  • SMDFlea
                    Super Moderator
                    • Jan 2018
                    • 20326
                    • UK

                    #10
                    Originally posted by Brown sugar builds

                    Ahh ok. Then the mosfets look something like
                    64 UUB
                    6W0K04 or 6W0KD4
                    G4 UUB , G4 *** PE616BA https://www.badcaps.net/forum/troubl...86#post1672286
                    All donations to badcaps are welcome, click on this link to donate. Thanks to all supporters

                    Comment

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