Transformer pins common to ground

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  • Ashroyer05
    Senior Member
    • Sep 2013
    • 162
    • U.S

    #1

    Transformer pins common to ground

    I have a couple transformers on this board I'm working on and all but a couple (which I don't think are connected to anything) show continuity to ground. Surely not all of them should go to ground right?
  • selldoor
    Slow Learner
    • Dec 2010
    • 7870

    #2
    Re: Transformer pins common to ground

    It may not matter - if they are not connected to anything in the transformer. It is just a locating pin soldered to help anchor the transformer.
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment

    • Ashroyer05
      Senior Member
      • Sep 2013
      • 162
      • U.S

      #3
      Re: Transformer pins common to ground

      Hmmm....I didn't know that. So if I suspect something from a transformer sounds like it's always a good idea to pull it and inspect. Thanks.

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #4
        Re: Transformer pins common to ground

        On the secondary side of the transformers (I.E. two power supply with common ground ref on the secondary side) one pin of each transformer will be connected to the secondary side common ground, the other end of the transformer winding will feed for example the Anode of the rectifier Diode. So if you take the resistance reading on the Anode pin of one of the transformer to another Anode of the diode of that is connected to the pin of the other transformer, it will show low reading due to low DCR of the transformer winding.
        Best way to learn is to draw up the schematic.
        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

        Comment

        • selldoor
          Slow Learner
          • Dec 2010
          • 7870

          #5
          Re: Transformer pins common to ground

          As you say I think you have to suspect it first else it is a lot of effort. You dont say what
          type of transformer main power?, inverter? Inverter ones often have 2 spare legs
          some have more.
          Please upload pictures using attachment function when ask for help on the repair
          http://www.badcaps.net/forum/showthread.php?t=39740

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #6
            Re: Transformer pins common to ground

            Example Diagram.
            Attached Files
            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

            Comment

            • Ashroyer05
              Senior Member
              • Sep 2013
              • 162
              • U.S

              #7
              Re: Transformer pins common to ground

              Thanks bud I will study that. I can't get schematics on these things. I'm not sure what type of transformer. I've tested transformers in school but never had to identify ones in tvs. But most of the pins running from the transformers are in the same trace on the board and they all run to ground.

              Comment

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