Lg55ls4500 no power

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  • TvNewb23
    Member
    • Feb 2016
    • 19
    • USA

    #1

    Lg55ls4500 no power

    Hi all, long time lurker. I've got this tv and the tv will not power on. There is no standby light on the tv and I'm not sure where to start. I've done a few tv repairs. Led change out and replaced a few bad caps on a couple but this one has no obvious signs and looking to learn some troubleshooting on this one. I did test the unit for 3.5 v and it has that. Didn't see a printed stby so I'm not clear if I tested the standby power. I attached a few pics for reference
    Attached Files
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Lg55ls4500 no power

    https://www.badcaps.net/forum/attach...9&d=1503527243

    You need to report the DCV reading of all 24 pins on that connector.
    The exposed pins you are seeing on the top side of the board are the ODD number pin, pin 1 is on the right most where the black dot is and that pin is 'PWR-ON'. The even number pin you will have to probe from the back side of the connector where the wires go into the connector.
    You MUST put down the pin name and follow by the DCV reading of each pin.
    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

    • TvNewb23
      Member
      • Feb 2016
      • 19
      • USA

      #3
      Re: Lg55ls4500 no power

      Bud,
      What a quick reply, rather than me making a chart for all 24 pins

      All voltages are 0vdc other than pins 9-12 which have the 3.5vdc as marked

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #4
        Re: Lg55ls4500 no power

        So other pins have no reaction when the power switch is activated? If that is the case then your main board is dead, it is not sending any command signals at all. Something is locking out the board.
        We need to see the whole back side of the TV showing all the boards and how they are connected together.
        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

        • TvNewb23
          Member
          • Feb 2016
          • 19
          • USA

          #5
          Re: Lg55ls4500 no power

          Bud, You are correct, no reaction from power button, or remote It is also worth mentioning this set does not have physical buttons for power, volume etc. just touch. .. pics of overall set attached.

          Thanks again.
          Attached Files

          Comment

          • maxvalutech
            Badcaps Veteran
            • Dec 2014
            • 804
            • australia

            #6
            Re: Lg55ls4500 no power

            Surely with no standby light you check voltage on main cap then if OK force PSU on for correct voltages being produced and if OK then to main . But no standby light = ????

            Comment

            • TvNewb23
              Member
              • Feb 2016
              • 19
              • USA

              #7
              Re: Lg55ls4500 no power

              So I jumped the 3.5v to pwr on. All voltages on that connector matched what was printed.

              Comment

              • aaronwt6
                Badcaps Veteran
                • Apr 2013
                • 855
                • US

                #8
                Re: Lg55ls4500 no power

                That would almost certainly point to a main board issue then. Replacing the main board should take care of the problem.

                Comment

                • TvNewb23
                  Member
                  • Feb 2016
                  • 19
                  • USA

                  #9
                  Re: Lg55ls4500 no power

                  Update, replaced main board and tv working great.

                  Comment

                  • budm
                    Badcaps Legend
                    • Feb 2010
                    • 40746
                    • USA

                    #10
                    Re: Lg55ls4500 no power

                    Thanks for the follow-up on the repair.
                    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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