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    Modifying LG Power Supply to prevent overdriving LEDs?

    I just fixed another LG 47” by swapping bad diodes for good ones. I noticed a repair service when googling that claims to modify your LG power supply to stop it from overdriving the LEDs and burning them out. Does anyone happen to know the gist of what they're doing as I'd like to do the same. I don't like repairing and reselling these TVs knowing the same problem will most likely pop up again.

    #2
    Re: Modifying LG Power Supply to prevent overdriving LEDs?

    im not sure on lgs this thread is regarding a vizio but may give you a idea on the mod
    https://www.badcaps.net/forum/showth...ed+current+mod

    Comment


      #3
      Re: Modifying LG Power Supply to prevent overdriving LEDs?

      maybe a starting point would be the cooling,
      i'v not seen a teardown yet that shows the led strips thermally coupled to the metalwork properly.

      Comment


        #4
        Re: Modifying LG Power Supply to prevent overdriving LEDs?

        Originally posted by stj View Post
        maybe a starting point would be the cooling,
        i'v not seen a teardown yet that shows the led strips thermally coupled to the metalwork properly.
        i wonder if when we replace/repair led strips does it matter what type of double sided tape we use as this could effect the cooling too i guess?

        Comment


          #5
          Re: Modifying LG Power Supply to prevent overdriving LEDs?

          I have been pressing the strips back down and hot gluing the edges to keep them in place as well as creating some glue straps across the raised “pegs” that are used to keep the strips in the right place. As far as I can tell the cooling effectiveness should be factory. If the driver is driving them at a higher current than they’re rated for then the cooling won’t matter in the long run because they’ll still burn out. I noticed several diodes that were much dimmers than others when testing them with my multimeter so I can only assume they are next to fail as their resistance is increasing.

          Comment


            #6
            Re: Modifying LG Power Supply to prevent overdriving LEDs?

            Originally posted by curt2199 View Post
            As far as I can tell the cooling effectiveness should be factory.
            that's not saying much these days!

            Comment


              #7
              Re: Modifying LG Power Supply to prevent overdriving LEDs?

              The LED PCB strip has no thermal VIA's to conduct the heat from the top layer to the bottom layer so the way it is right now the heat transfer from the top layer to the bottom layer is joke, and if they do add the VIA's then then will have to add electrical insulation between the strip and the metal chassis.
              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


                #8
                Re: Modifying LG Power Supply to prevent overdriving LEDs?

                i thought all the tv strips used aluminium pcb's??

                Comment


                  #9
                  Re: Modifying LG Power Supply to prevent overdriving LEDs?

                  It would have been nice but that costs more than just simple double sided copper clad board, they have to cut cost and make sure they go bad after the warranty runs out.
                  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


                    #10
                    Re: Modifying LG Power Supply to prevent overdriving LEDs?

                    Picked up another 47 and 55 tonight. Lot of these LGs with dead leds.

                    Comment


                      #11
                      Re: Modifying LG Power Supply to prevent overdriving LEDs?

                      Originally posted by curt2199 View Post
                      Picked up another 47 and 55 tonight. Lot of these LGs with dead leds.
                      You may find them with badly burn out LED's:
                      https://www.badcaps.net/forum/showth...hlight=latw%2A

                      https://www.badcaps.net/forum/showth...ht=LG+47LN5790
                      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


                        #12
                        Re: Modifying LG Power Supply to prevent overdriving LEDs?

                        Just replaced one bad diode on the 55”. Time to put it back together. Gave the guy $40 for the TV last night. Alsways nice when a plan comes together. Lol. Now to do the same to the 47” to upgrade my bedroom tv.
                        Attached Files

                        Comment


                          #13
                          Re: Modifying LG Power Supply to prevent overdriving LEDs?

                          Just make sure to turn down the backlights level to as low as possible on ALL input settings.
                          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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