5VSB voltage oscilating - CWT PSF400S

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  • andrewdh
    New Member
    • Apr 2012
    • 4
    • Australia
    #1

    5VSB voltage oscilating - CWT PSF400S

    Hi there all - a newbie to this forum

    I have a CWT PSF400S-30 (photo attached) and using a basic power supply tester the voltage on the 5VSB output is oscilating all over the place between about 4.5 and 5.2.

    All the other outputs are steady within scope

    Also when you turn it off you hear a phhuushing/hissing type of sound for about 3 seconds

    Any suggestions or toss it?



    Regards
    Andrew
    Attached Files
    Tags: None
    • selldoor
      Slow Learner
      • Dec 2010
      • 7870
      #2
      Re: 5VSB voltage oscilating - CWT PSF400S

      Are there more caps under the heat sink? are they or the small ones we cant see or the small ones on the side board bulged or leaking. Can you pin down where the sound is from.
      Does it fail to power up the PC.
      By coincidence I think this may have been reviewed on line by one of our members and
      perhaps they will comment later
      http://hardwareinsights.com/wp/2011/...00s-30-review/
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

        Comment

        • 999999999
          Badcaps Veteran
          • Sep 2006
          • 774
          • USA
          #3
          Re: 5VSB voltage oscilating - CWT PSF400S

          1st guess is replace the caps in the 5VSB subcircuit, probably a couple smaller electrolytics near the front middle of the PCB. If the tester isn't placing a small load on 5VSB, do that too for the measurement.

            Comment

            • andrewdh
              New Member
              • Apr 2012
              • 4
              • Australia
              #4
              Re: 5VSB voltage oscilating - CWT PSF400S

              Thanks for the reply

              I have taken some more pics and grabbed one from the link you posted.
              Note the two caps with red circles under the heat sink in pic .....002.jpg are slightly rounded on top.

              Also the two pics (005 and 006) are of the back side line up using the red circle with 005.jpg being under the heatsinks.

              I plugged it into an Intel D915GAV mobi and the attached pic shows the power ready from the BIOS. However the second I turned on the PSU power switch on the back of the PSU (mains already live) the CPU fan started and the device cables were all live BUT the POST did not start until I pushed the front switch.

              At that stage it booted fine however you can hear a sound similar to a "slightly" noisy fan bearing coming from the PSU. It is still there even if the PSU fan is removed momentarily.

              Exited POST and shutdown with font switch - CPU fan keeps going

              A real weird issue this one but maybe one of you experts can pinpoint the issue. Normally I would toss it but I am keen to learn more about what ticks or does not tick in these

              The article you referred to states they are a decent quality PSU with dual 12 volt rails

              Regards
              Andrew
              Attached Files

                Comment

                • 999999999
                  Badcaps Veteran
                  • Sep 2006
                  • 774
                  • USA
                  #5
                  Re: 5VSB voltage oscilating - CWT PSF400S

                  Yes definitely replace the two bulged caps and retest.

                    Comment

                    • andrewdh
                      New Member
                      • Apr 2012
                      • 4
                      • Australia
                      #6
                      Re: 5VSB voltage oscilating - CWT PSF400S

                      Originally posted by 999999999
                      Yes definitely replace the two bulged caps and retest.
                      Sounds like a job for the weekend seeing tomorrow last day before easter.

                      Thanks people - will keep you informed.

                      BTW - anyone know much about PCB boards for Automatic Coffee Machines - have about 6 to fix (maybe better in a different thread) - mosfet's galore!!!

                        Comment

                        • ben7
                          Capaholic
                          • Jan 2011
                          • 4059
                          • USA
                          #7
                          Re: 5VSB voltage oscilating - CWT PSF400S

                          Yeah, replace all the fuhjyyu capacitors too, they are a crappy brand.
                          Hissing usually is from a loose transformer core or from voltage ripple that doesn't get filtered out by [bad] capacitors.

                          BTW - anyone know much about PCB boards for Automatic Coffee Machines - have about 6 to fix (maybe better in a different thread) - mosfet's galore!!!
                          That would be interesting, although I don't know anything about them.

                          -Ben
                          Last edited by ben7; 04-04-2012, 10:11 AM.
                          Muh-soggy-knee

                            Comment

                            • rogfanther
                              Badcaps Veteran
                              • Jul 2006
                              • 458
                              • Brazil
                              #8
                              Re: 5VSB voltage oscilating - CWT PSF400S

                              From c_hedge article, this psu is full of Fujhyus. They are replace on sight. Replace all of them then retest.

                                Comment

                                • c_hegge
                                  Badcaps Legend
                                  • Sep 2009
                                  • 5219
                                  • Australia
                                  #9
                                  Re: 5VSB voltage oscilating - CWT PSF400S

                                  Yup. I had exactly the same problem with the one I reviewed on Hardware Insights. The 5vsb caps went bad and it mad a horrible squeal when plugged in. The other caps were probably not far off failing, judging by the high ripple. I still have the PSU, but it has been recapped with panny FC and FK.
                                  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

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