LG 49LB5500 flashing as soon as plugged in

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  • frannyjunk
    Senior Member
    • Oct 2010
    • 78
    #1

    LG 49LB5500 flashing as soon as plugged in

    So I have this LG TV that started flashing. Thinking the symptoms were consistent with backlight issues, I replaced them. But the problem persisted. The flashing is a little odd in that the LEDs are not very bright when flashing. So I put my voltmeter on the LED socket on the power supply board and the voltage cycles between 30 and 90 volts (backlight plug not plugged in). I am assuming the voltage cycling is not normal, right? When I disconnect the cable to the mainboard, the LED socket reads 0V. Any idea if this is a power supply board issue? Or is it the mainboard? How can I check? What component might be bad?

    Any suggestions would be much appreciated. Thanks!
    Attached Files
    Last edited by frannyjunk; 04-19-2022, 09:10 PM.
    Tags: None
    • neilc6
      Badcaps Legend
      • Nov 2015
      • 1550
      • Canada
      #2
      Re: LG 49LB5500 flashing as soon as plugged in

      Flashing on LB series is bad backlights. There is something wrong with your replacement strips.

        Comment

        • frannyjunk
          Senior Member
          • Oct 2010
          • 78
          #3
          Re: LG 49LB5500 flashing as soon as plugged in

          Originally posted by neilc6
          Flashing on LB series is bad backlights. There is something wrong with your replacement strips.
          I tested every strip of the new backlight, and they all seem fine. Does the cycling voltage at the LED socket from the power supply board indicate anything?

            Comment

            • neilc6
              Badcaps Legend
              • Nov 2015
              • 1550
              • Canada
              #4
              Re: LG 49LB5500 flashing as soon as plugged in

              A LED tester only puts out 15 to 20 mA while the TV runs at several hundred and may not detect bad strips. Record the flash with the panel removed and see what LEDs are not lighting up.

                Comment

                • yokoono
                  Badcaps Veteran
                  • Apr 2010
                  • 486
                  #5
                  Re: LG 49LB5500 flashing as soon as plugged in

                  The LB series is equipped with 6V LEDs and a large magnifying glass. Very bad LEDs.

                    Comment

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