Lg 55LM6700 steady backlight no on screen display, pic, or sound

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  • snake91876
    Badcaps Veteran
    • Feb 2013
    • 236
    • United States

    #1

    Lg 55LM6700 steady backlight no on screen display, pic, or sound

    I have a LG 55lm6700 when I press power turns on like normal with a steady backlight. I have no onscreen display , pic , or sound. Below are the boards.
    Attached Files

    if you find these attachements useful please consider making a small donation to the site

  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

    Do you know the history of this TV?
    It uses one of those tab bonding board on the bottom edge of the panel which gets damaged when people spray cleaning fluid on the screen.
    Fuse on the T-CON has 12VdC on both ends with ref. to GND?
    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

    • snake91876
      Badcaps Veteran
      • Feb 2013
      • 236
      • United States

      #3
      Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

      I don't know any history I got it from a guy at a recycling center

      Comment

      • snake91876
        Badcaps Veteran
        • Feb 2013
        • 236
        • United States

        #4
        Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

        TV has no tcon, 2 cables go straight from main board

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

          Originally posted by snake91876
          TV has no tcon, 2 cables go straight from main board
          LCD panel with integrated T-CON then, so you will have to get the metal bezel of the LCD panel off to get to the T-CON to check the fuse.
          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

          • snake91876
            Badcaps Veteran
            • Feb 2013
            • 236
            • United States

            #6
            Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

            It's got two cables going to two small boards on bottom of panel are those tcon or is there a separate one.

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

              Those are the boards.
              What is the LCD panel model so we can look up the spec sheet for it?
              Last edited by budm; 06-17-2016, 08:37 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

              • snake91876
                Badcaps Veteran
                • Feb 2013
                • 236
                • United States

                #8
                Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

                Here's pic of panel sticker
                Attached Files

                if you find these attachements useful please consider making a small donation to the site

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #9
                  Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

                  check to see if you get VDD at both LVDS cables to the LCD panel, you can try probing them on the main board side, at least one of those pin should show 16Vdc (typ.)
                  Attached Files

                  if you find these attachements useful please consider making a small donation to the site

                  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

                  • jabase
                    New Member
                    • Jun 2016
                    • 7
                    • USA

                    #10
                    Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

                    scope the lines of the LVDS to see if there is video going to the panel. That will tell you if you have panel or main board issue..

                    Comment

                    • snake91876
                      Badcaps Veteran
                      • Feb 2013
                      • 236
                      • United States

                      #11
                      Re: Lg 55LM6700 steady backlight no on screen display, pic, or sound

                      Well bad news guys I didn't follow instructions and tried probing at panel pins and shorted something. I have lines in picture now vertically everywhere. I guess this panel is toast.

                      Comment

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