FSP Group ATX-400PNF

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  • maxd
    Member
    • Aug 2012
    • 11
    • ‎
    #1

    FSP Group ATX-400PNF

    Hello, everyone.

    Yesterday I took out USB flash drive from back of PC and computer turned off. Didn't think much about that and wen to bed.
    At the morning PC didn't turn on. I opened PSU, checked fuse, it was okay.
    Then disconnected PSU from PC components and turned it on. Voltage on 12V rail was in ~12,7-13,1V range. Obviously too high.
    Then I spotted tiny potentiometer on one of PCBs and thought - what the heck, let's try to turn it and see what happens. That turned out to be voltage adjustment for 12V rail and probably other riles too. I adjusted 12V rail voltage with all components connected to about 11,75V and now this PC aparently works fine.

    Question: Do You have an idea what have caused voltage drift in the first place? Could it be dying secondary caps, tiny caps on PCB where potentiometer is, or something else?

    All caps in this PSU are original, except one (one Jamicon 3300uF/10V has been changed some time ago).

    In the attatched picture is noted potentiometer I adjusted.
    Attached Files
    Last edited by maxd; 10-22-2014, 11:12 PM.
    Tags: None
    • c_hegge
      Badcaps Legend
      • Sep 2009
      • 5219
      • Australia
      #2
      Re: FSP Group ATX-400PNF

      The higher voltage may very well be normal when the PSU has no load on it. Some PSUs need a load in order to regulate properly. It may just have been the act of re-seating the connector that fixed the problem.
      I love putting bad caps and flat batteries in fire and watching them explode!!

      No wonder it doesn't work! You installed the jumper wires backwards

      Main PC: Core i7 3770K 3.5GHz, Gigabyte GA-Z77M-D3H-MVP, 8GB Kingston HyperX DDR3 1600, 240GB Intel 335 Series SSD, 750GB WD HDD, Sony Optiarc DVD RW, Palit nVidia GTX660 Ti, CoolerMaster N200 Case, Delta DPS-600MB 600W PSU, Hauppauge TV Tuner, Windows 7 Home Premium

      Office PC: HP ProLiant ML150 G3, 2x Xeon E5335 2GHz, 4GB DDR2 RAM, 120GB Intel 530 SSD, 2x 250GB HDD, 2x 450GB 15K SAS HDD in RAID 1, 1x 2TB HDD, nVidia 8400GS, Delta DPS-650BB 650W PSU, Windows 7 Pro

        Comment

        • maxd
          Member
          • Aug 2012
          • 11
          • ‎
          #3
          Re: FSP Group ATX-400PNF

          PSU voltages were too high with load. Some OVP kicked in and that's why PC didn't turn on. After adjusting first without load and after that with running PC everything seems ok. But still it is not clear why this happened.

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