Flickery Backlights in LG L246WH

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  • canadaboy25
    What is normal?
    • May 2013
    • 509
    • Canada
    #1

    Flickery Backlights in LG L246WH

    Hello I have an LG Flatron L246WH Monitor that I got for free.

    At first It had a bad fuse, MOSFET, and diode. I replaced all and then it was working fine. A while later I took it in a trip in our trailer. It must have gotten bumped on the ride because when we got there there were no backlights. The lights would sometimes come on when I bumped the backside of the monitor. Now they will not come on at all. All of the caps and diodes are fine. The problem is on the power supply board because when I test it there is no 12v or 24v going to the inverter board. The bridge rectifier is good and so are the MOSFETS. I have taken the transfomers off but I don't know how to test them. I have a digital multimeter.

    Any guidance would be appreciated.
    canadaboy25

    -Sometimes the light at the end of a tunnel is an on-coming train
    Tags: None
    • 1supertech
      Badcaps Veteran
      • Apr 2012
      • 384
      • USA
      #2
      Re: Flickery Backlights in LG L246WH

      check this site http://preher-tech.com/documents/tes...ormersinlcdtvs
      also check your CCFL bulbs one may be broken.

        Comment

        • canadaboy25
          What is normal?
          • May 2013
          • 509
          • Canada
          #3
          Re: Flickery Backlights in LG L246WH

          Originally posted by 1supertech
          check this site http://preher-tech.com/documents/tes...ormersinlcdtvs
          also check your CCFL bulbs one may be broken.
          My ccfls and trasformers are fine. The power supply board and inverter board are two seperate ones. My power supply board is not outputting 12v or 24v to the inverter board. I took the transformers off of the power supply board and wanted to test them with a multimeter.
          canadaboy25

          -Sometimes the light at the end of a tunnel is an on-coming train

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA
              #4
              Re: Flickery Backlights in LG L246WH

              I doubt it very much that it is bad transformer, since you can bump it to make it come on before and now it is dead, I would inspect the solder joints closely. You should also check to see if you have 170vdc on the main cap right now.
              Do you still have 5V? Pictures of the boards?
              Last edited by budm; 11-26-2013, 08:02 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

                • canadaboy25
                  What is normal?
                  • May 2013
                  • 509
                  • Canada
                  #5
                  Re: Flickery Backlights in LG L246WH

                  I re-soldered all of the through hole components and now it is working.

                  It must have been a craked solder joint.
                  canadaboy25

                  -Sometimes the light at the end of a tunnel is an on-coming train

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA
                      #6
                      Re: Flickery Backlights in LG L246WH

                      Glad to hear it is working now.
                      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

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