42" LG no backlights

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  • gilly1984
    Badcaps Veteran
    • Jun 2012
    • 751
    • UK

    #21
    Re: 42" LG no backlights

    Just solder a wire across where the component fell off. But make sure there is no bronze showing on the trace inbetween the 2 points to be connected.

    EDIT;

    As bud said, better check for shorts before patching it up with a wire.
    Last edited by gilly1984; 10-23-2012, 09:55 AM. Reason: Ahead of myself.
    Do NOT touch heatsinks when testing for voltages as they may be LIVE!

    Comment

    • cbriggz
      Member
      • Oct 2012
      • 18
      • USA

      #22
      Re: 42" LG no backlights

      what about the other spots i highlighted they look burnt too?? Should i just order a new board?

      Comment

      • gilly1984
        Badcaps Veteran
        • Jun 2012
        • 751
        • UK

        #23
        Re: 42" LG no backlights

        It may just be that they run quite warm, check for shorts and then patch up where that 0 ohm jumper went. Those other burn marks are where the other larger jumpers are.

        It doesnt have to be super hot to make them marks.
        Do NOT touch heatsinks when testing for voltages as they may be LIVE!

        Comment

        • cbriggz
          Member
          • Oct 2012
          • 18
          • USA

          #24
          Re: 42" LG no backlights

          the one spot is not where a jumper is. i circled where it is on the pic. That part also makes a strange noise when i plug in the television. It is the first one on the top of the board. not the one pictured
          Attached Files

          Comment

          • gilly1984
            Badcaps Veteran
            • Jun 2012
            • 751
            • UK

            #25
            Re: 42" LG no backlights

            I better leave it to someone more in the know.
            Do NOT touch heatsinks when testing for voltages as they may be LIVE!

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #26
              Re: 42" LG no backlights

              That burnt jumper supplies the power to U8. That part has 5 pins, so take the resistance reading between all the pins, with the big tab on top, make the left pin as pin 1, then take the reading between pin
              1&2
              1&3
              1&4
              1&5
              2&3
              2&4
              2&5
              3&4
              3&5
              4&5

              The transformer you have circle, you will have to do the same resistance checking between all the pins and compare the readings to the one next to it. I did not find the pinout of the transformer yet.
              Also look on line for the replacement board.
              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

              • cbriggz
                Member
                • Oct 2012
                • 18
                • USA

                #27
                Re: 42" LG no backlights

                found replacement board on ebay for 45 dollars. Do you think that will solve my problem??

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #28
                  Re: 42" LG no backlights

                  Well, we already know you have burnt out component on the board, so we know at least that the board is bad, cannot tell if there are any other problem with other boards on the TV.
                  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

                  • cbriggz
                    Member
                    • Oct 2012
                    • 18
                    • USA

                    #29
                    Re: 42" LG no backlights

                    ok well for the price i will give it a try, wife bought me a new 55 LED so this is really just a learning lesson(and to prove that i can fix it lol). Thanks again will post when i get the new board.

                    Comment

                    • gilly1984
                      Badcaps Veteran
                      • Jun 2012
                      • 751
                      • UK

                      #30
                      Re: 42" LG no backlights

                      That's cheating
                      Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                      Comment

                      • cbriggz
                        Member
                        • Oct 2012
                        • 18
                        • USA

                        #31
                        Re: 42" LG no backlights

                        hahaha replacing the board or buying a new TV???

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #32
                          Re: 42" LG no backlights

                          Well, at least check out U8 as I posted in post 26 to find out taht is the reason the jumper burtn up. Then you will still have the transformers to deal with.
                          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

                          • cbriggz
                            Member
                            • Oct 2012
                            • 18
                            • USA

                            #33
                            Re: 42" LG no backlights

                            i will can you tell me what U8 is please lol. Remember im new at this!!!

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #34
                              Re: 42" LG no backlights

                              You can see it in your picture in post 18, it is a 5-pins MOSFETs. it has that burnt jumper copnnected to one of its leg.
                              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

                              • gilly1984
                                Badcaps Veteran
                                • Jun 2012
                                • 751
                                • UK

                                #35
                                Re: 42" LG no backlights

                                Originally posted by cbriggz
                                hahaha replacing the board or buying a new TV???
                                Both
                                Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                                Comment

                                • cbriggz
                                  Member
                                  • Oct 2012
                                  • 18
                                  • USA

                                  #36
                                  Re: 42" LG no backlights

                                  this one right
                                  Attached Files

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #37
                                    Re: 42" LG no backlights

                                    That is it. Test it per post 26.
                                    Your transformer pinout may be like this for the high voltage windings:
                                    http://s807.photobucket.com/albums/y...t=DSC01034.jpg
                                    Attached Files
                                    Last edited by budm; 10-23-2012, 03:35 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

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