DELL XPS 13 7390 no power, short 5alw & 3alw

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  • pc_okay
    Badcaps Veteran
    • May 2022
    • 241
    • FRANCE

    #1

    DELL XPS 13 7390 no power, short 5alw & 3alw

    Hello guys,

    I have this board, taking no voltage on usb-c.
    After some diging, i found that 5alw (1ohm to ground) & 3alw (7ohms to ground) are both short to ground
    So i open jumps @PJP300 & @PJP401 and found no shortage on both 5alwP & 3alwp.

    So i try to inject on both 3alw & 5alw with no luck: i get some heat on UC22 & UC23 but that's all.

    And now i'm stuck.

    Please find attach schematics. Link to schematic --> https://www.badcaps.net/forum/troubl...15#post1661615

    Any ideas?

    Thanks !
    Last edited by SMDFlea; 09-25-2024, 03:53 AM. Reason: Link to schematic
  • mon2
    Badcaps Legend
    • Dec 2019
    • 14118
    • Canada

    #2
    With no power to the board, what is the resistance to ground of:

    +3VALW
    +5VALW


    NB: Best to copy & paste the full net names from the schematic so they are easier to follow in the review.

    Comment

    • pc_okay
      Badcaps Veteran
      • May 2022
      • 241
      • FRANCE

      #3
      +3VALW 1 ohm
      +5VALW 7ohms

      thanks

      Comment

      • mon2
        Badcaps Legend
        • Dec 2019
        • 14118
        • Canada

        #4
        These are very low resistance measurements. For your injection, keep the voltage @ 1v but increase the current to 3A-5A range. Inject again to check who heats up.

        Comment

        • pc_okay
          Badcaps Veteran
          • May 2022
          • 241
          • FRANCE

          #5
          Hello,

          UC22 heat @ 70°C~ taking 1.5 amp max.

          Thanks.

          Comment

          • pc_okay
            Badcaps Veteran
            • May 2022
            • 241
            • FRANCE

            #6
            Hello,

            I'm still stuck with this board, i remove the UC22 but still get low resistance, i inject again and another chip heat : UPD2.
            I remove it but still get low res !


            When i remove UPD1 i get a correct resistance to ground on +3VALWonly.

            Any idea?

            Comment

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