Where's my 24V ???

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  • fingermcginty
    New Member
    • Feb 2017
    • 3
    • Ireland

    #1

    Where's my 24V ???

    Troubleshooting a simple circuit today in a PD panel . There is a small 24V power supply on the DIN rail. .It has line voltage on the input and 24V DC on it's outputs across the (-ve) and (+ve) terminals. Schematic says the (+ve) is connected to a fuse and then runs onto the rest of the circuit.
    I thought there was a break between (+ve) and the power supply side of the fuse because when i measured between the panel door grounding point and the power supply side of the fuse I wasn't getting 24V DC on the meter. Would I be right in saying the above condition would be true if the power supply wasn't grounded ?
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Where's my 24V ???

    Do you know if the -VE is tied/connected to the panel/chassis?
    Pictures of what we are dealing with?
    The more info we get the better help you will get.
    Last edited by budm; 02-17-2017, 02:52 PM.
    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

    • fingermcginty
      New Member
      • Feb 2017
      • 3
      • Ireland

      #3
      Re: Where's my 24V ???

      Originally posted by budm
      Do you know if the -VE is tied/connected to the panel/chassis?
      I think that's the problem right there. I was assuming that the -ve is always tied to chassis ground but apparently not.

      Comment

      • fionaan
        New Member
        • Mar 2018
        • 2
        • USA

        #4
        Re: Where's my 24V ???

        Originally posted by fingermcginty
        Troubleshooting a simple circuit today in a PD panel . There is a small 24V power supply on the DIN rail. .It has line voltage on the input and 24V DC on it's outputs across the (-ve) and (+ve) terminals. Schematic says the (+ve) is connected to a fuse and then runs onto the rest of the circuit.
        I thought there was a break between (+ve) and the power supply side of the fuse because when i measured between the panel door grounding point and the power supply side of the fuse I wasn't getting 24V DC on the meter. Would I be right in saying the above condition would be true if the power supply wasn't grounded ?
        i suspect the problem is a simple but large part

        Comment

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