Low Standby voltage on Dell PSU

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  • Gatolina
    Member
    • Jan 2023
    • 10
    • Brasil
    #1

    Low Standby voltage on Dell PSU

    Hello! I'm trying to fix this Dell ATX PSU H235PD-01 which had a burned tny279 for the 5V Standby.

    I've changed it, checked the capacitors and diodes. Now I have 5.8V in pin 2 (bypass), 358V in Drain (pin 4), reaching the primary of the transformer but only 0.7v outputting to Standby purple wire.

    What could be the problem? Thank you
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    • R_J
      Badcaps Legend
      • Jun 2012
      • 9535
      • Canada
      #2
      Re: Low Standby voltage on Dell PSU

      You are missing the feedback voltage from the transformer Check the feedback diode,resistor and replace the electrolytic on that line.

        Comment

        • Gatolina
          Member
          • Jan 2023
          • 10
          • Brasil
          #3
          Re: Low Standby voltage on Dell PSU

          Thanks for the reply. I'll check that. Best regards

            Comment

            • Gatolina
              Member
              • Jan 2023
              • 10
              • Brasil
              #4
              Re: Low Standby voltage on Dell PSU

              If someone else is having the same problem, it was a zener diode connected to the En pin (pin 1) that was faulty.

                Comment

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