lg 42ln5700 no power, no standby light

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  • StinkyOnion
    New Member
    • Dec 2015
    • 6
    • United States

    #1

    lg 42ln5700 no power, no standby light

    PO claims tv was hit by lightning. Checked standby voltages on the two pins on the ps board going to main board and measured 7v on both. Also checked transformer el47 and got no reading and a .3 reading on a capacitor labeled c508. This all before I believe I blew the fuse closest to cord plug in. Now the fuse is reading 120v one side and .3 the other and so is pretty much every other ic is the approx. reading.

    This is my first attempt at tv repair so any constructive criticism is greatly appreciated.ty
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: lg 42ln5700 no power, no standby light

    You can start by uploading good clear pictures of the back side of the TV so we can see how all the boards are connected together, then the pictures of the whole power supply board.
    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

    • StinkyOnion
      New Member
      • Dec 2015
      • 6
      • United States

      #3
      Re: lg 42ln5700 no power, no standby light

      I found a service manual for another similar model but I was hoping to apply it to this tv
      Attached Files

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #4
        Re: lg 42ln5700 no power, no standby light

        So both fuses are blown?
        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

        • StinkyOnion
          New Member
          • Dec 2015
          • 6
          • United States

          #5
          Re: lg 42ln5700 no power, no standby light

          Only the fuse closest to the plug is blown. The other fuse is reading .3 all the way across

          Comment

          • StinkyOnion
            New Member
            • Dec 2015
            • 6
            • United States

            #6
            Re: lg 42ln5700 no power, no standby light

            Fried the board with my Weller 40 watt iron at max setting attempting to desolder a fuse. Got most of the components out. It was an awesome newbie experience. I'm wondering if I should purchase the Ps board and progress my diagnosis or start on another r&d project.
            Last edited by StinkyOnion; 12-28-2015, 09:31 AM.

            Comment

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