lg37lv355t backlight off and on

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  • hispeck
    Badcaps Veteran
    • Aug 2015
    • 258
    • nigeria
    #1

    lg37lv355t backlight off and on

    Hello, This led tv , customer said sometme tv will work for about 2hrs then the backlight will go off while tv remain on with sound, after i opened the tv to backlight stage, and power on the tv, i fund out that backlight is going off, this backlight is mounted by the side of the chassis and each side contains about 60 diodes led bulbs, sometime half 30 will just go off on each side but when i take off the power cord and put back the same lght will come on again, i has tested all the buld they light fine, only that few look browness, but they all light fine, here is the led driver board. T315HW07 V8 31T14-D06, is there any way to test this back light? from the psu came 24v to led driver
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    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA
      #2
      Re: lg37lv355t backlight off and on

      When you test the LED how much current did you drive through the LEDs?
      LED may test good at low current, but it will fail at operating current which is 200 ~ 400mA typ.
      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

        • hispeck
          Badcaps Veteran
          • Aug 2015
          • 258
          • nigeria
          #3
          Re: lg37lv355t backlight off and on

          Originally posted by budm
          When you test the LED how much current did you drive through the LEDs?
          LED may test good at low current, but it will fail at operating current which is 200 ~ 400mA typ.
          Am sorry i dont have led tester yet, but hope to get one soon, but can you please show another way to test if?

            Comment

            • hispeck
              Badcaps Veteran
              • Aug 2015
              • 258
              • nigeria
              #4
              Re: lg37lv355t backlight off and on

              I noticed that if i use DMM to test each of the diode bulb, some will light and stay on , but will light and drop . also with Anolog MM it will stay on but i will notice some are brither

                Comment

                • Andrew F. Ali
                  Badcaps Legend
                  • Jan 2014
                  • 2450
                  • Trinidad & Tobago
                  #5
                  Re: lg37lv355t backlight off and on

                  OK. That testing you did tells you that you need to change out ALL the LED strips. TV fixed.

                    Comment

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