PSU load tester

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  • mike9h29
    Senior Member
    • Mar 2011
    • 60
    #1

    PSU load tester

    Hi,

    I need to test some pc power supplies. I have a PSU tester, but this does not load the psu.

    Is there a way to test a pc psu under test please?

    I`ve red about using resistors or car bulbs. is there a circuit diagram for a load tester using resistors please?

    Thanks

    Mario
    Tags: None
    • c_hegge
      Badcaps Legend
      • Sep 2009
      • 5219
      • Australia
      #2
      Re: PSU load tester

      https://www.badcaps.net/forum/showthread.php?t=11194 I actually built one myself. Mine will go up to 720W, but you can go higher by adding more resistors.
      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

        • Jack Crow
          It's a CLASOB!
          • May 2008
          • 823
          • USA
          #3
          Re: PSU load tester

          Guys
          Q for you.
          You never had to make a 'solid state' load tester for a project?
          It's a lot like a standard linear power supply used 'in reverse'.

          Years ago we had a solid state bench load instrument for that reason at PRD. You can find them now for about 400 bucks from various sources.

          If you don't need fancy displays and careful current regulation some short cuts can be had.

          Since it's cheap it has some limits.
          For example the current draw is not stable with heat.
          As bi polar transistors heat up they tend to conduct more current until failure point.
          What was that old song by Del Shannon, Thermal Run Away?

          But for quick testing this thing can suck down 25 amp and I can get a vlaid ripple reading. (12 volt inputs, a little less on lower voltages since there is a lower limit to internal resistance of the solid state load bank. Used it to test 50 amp Astron units used in the ham radio community.

          I have a 'butt ugly' one I made 20 years ago and it still works.
          Some parts have melted out of the case but they still run.

          It won't win a beauty contest.

          It's three or four 2N3055 in parallell.
          The transistors are driven with a variable current from the + input.
          A fan blows across the transistors mounted on a good heat sink.

          With PC style power systems, the key load is the +3 or +5, if that works good chance the rest will play along as well.

          Might want to look into making one out of power mos fets with their super low turn on resistance.
          Get ten togther with .1 ohm turn on, and the result is a .01 ohm minimum power resistor at some real wattage.

          If your truly desperate and agree not to laugh, I can take some photos of the butt ugly unit and work up a sketch that won't be too hard to duplicate. Share a thought.

          Ideas guys.
          Jack Crow in the less than free world.
          "You are, what you do, when it counts"
          The Masso

          "Gravity, the quickest way down"
          Mayor John Almafi

          "You ever drop an egg, and on the floor you see it break?
          You go and get a mop so you can clean up your mistake.
          But did you ever stop to ponder why we know it's true?
          If you drop a broken egg you will not get an egg that's new?"

          MC Hawking

            Comment

            • Jack Crow
              It's a CLASOB!
              • May 2008
              • 823
              • USA
              #4
              Re: PSU load tester

              Guys
              This has been on the mind. Needed to follow up.

              Took my unit apart and used it as an example to draw up a schematic with a 'free' cad package I got from a PCB maker.
              Printed this sketch.

              Will 'scan' that and save it as a JPG.
              Then I will take some photos of my gad awful ugly unit, then turn the whole package into a small article you can look at on my Flickr page.

              Seems when I made this thing was in March 1994, I have not been able to kill it yet.

              Last year had a pair of 50 amp Astron units here for repair and they did not kill the unit.
              Used it to fix a bunch of 20 amp Astrons over the last few years.

              So I have not 'given up', will finish this directly.
              Be well all.
              Mike aka Jack Crow
              "You are, what you do, when it counts"
              The Masso

              "Gravity, the quickest way down"
              Mayor John Almafi

              "You ever drop an egg, and on the floor you see it break?
              You go and get a mop so you can clean up your mistake.
              But did you ever stop to ponder why we know it's true?
              If you drop a broken egg you will not get an egg that's new?"

              MC Hawking

                Comment

                • Jack Crow
                  It's a CLASOB!
                  • May 2008
                  • 823
                  • USA
                  #5
                  Re: PSU load tester

                  Ok,
                  Have a quick write up ready for you.
                  http://www.flickr.com/photos/9010884...th/5584455941/

                  Hope it helps.
                  Mike
                  "You are, what you do, when it counts"
                  The Masso

                  "Gravity, the quickest way down"
                  Mayor John Almafi

                  "You ever drop an egg, and on the floor you see it break?
                  You go and get a mop so you can clean up your mistake.
                  But did you ever stop to ponder why we know it's true?
                  If you drop a broken egg you will not get an egg that's new?"

                  MC Hawking

                    Comment

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