What are typical problems with this kind of psu behaviour?

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  • Trofazni
    Senior Member
    • Dec 2016
    • 71
    • Serbia

    #1

    What are typical problems with this kind of psu behaviour?

    It is ordinary 12V 5A psu, everything measures ok, what could be problem?

    https://youtu.be/-zwaUHZ2OCk
  • sam_sam_sam
    Badcaps Legend
    • Jul 2011
    • 6037
    • USA

    #2
    Re: What are typical problems with this kind of psu behaviour?

    Let see the plastic housing for this power supply data plate
    Also let see the front side and back side of the board close up

    This power supply looks very familiar to some power supply that I have
    Is this medical grade type power supply

    If this is the type of power supply all the capacitors need to be replaced except the the main capacitor can left alone ——> these are very good switching power supply

    I have quite a few of 5 volt @ 5 amp switching power supply and I always recap them the capacitors that they use are real crap

    I also have a few 12 volt @ 2.75 amp one also

    The photos are from the 12 volt @ 2.75 amp medical grade switching power supply

    On second thought this might not be the same type of power supply
    Attached Files
    Last edited by sam_sam_sam; 04-28-2019, 10:31 AM.

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    • PeteS in CA
      Badcaps Legend
      • Aug 2005
      • 3579
      • USA, Unsure of Planet

      #3
      Re: What are typical problems with this kind of psu behaviour?

      Hmmm, OVP shut down and restart? The low cold resistance of the halogen bulb is tripping over-current protection?

      Some of the solder joints near the board edge nearer the camera, roughly in the center of the board, look like they might have voids or cracks (a poor solder joint could open up if current passes through it).
      PeteS in CA

      Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
      ****************************
      To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
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      • petehall347
        Badcaps Legend
        • Jan 2015
        • 4426
        • United Kingdom

        #4
        Re: What are typical problems with this kind of psu behaviour?

        try incandescent bulb .start with 20w and work up .

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: What are typical problems with this kind of psu behaviour?

          You should check the cold resistance of that lamp you are using, as Petes suggested it may have trip the over current protection.
          Never stop learning
          Basic LCD TV and Monitor troubleshooting guides.
          http://www.badcaps.net/forum/showthr...956#post305956

          Voltage Regulator (LDO) testing:
          http://www.badcaps.net/forum/showthr...999#post300999

          Inverter testing using old CFL:
          http://www.badcaps.net/forum/showthr...er+testing+cfl

          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
          http://s807.photobucket.com/user/budm/library/

          TV Factory reset codes listing:
          http://www.badcaps.net/forum/showthread.php?t=24809

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          • Retro-Hipster
            Tinkerer
            • Apr 2019
            • 125
            • United States

            #6
            Re: What are typical problems with this kind of psu behaviour?

            You could use the whole "Diode gone wild" trick and essentially brush one of the leads on one of the halogen bulb contacts over and over quickly to help it warm up until it is lit/hot, then make the full connection.. that or don't go so janky and try something like an ntc thermistor between the bulb and the psu.. But what others have said on this one for sure.. most halogen bulbs have really low cold filament resistance. I'm using one of the 120v variety as a current limited supply on my bench right now. lol


            “Men always seem to think about their
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            – Jet (Cowboy Bebop) -

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