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55ln620v LG flash then no backlight

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    55ln620v LG flash then no backlight

    as above took set apart down to leds all leds light using
    multi meter
    any ideas what I should check
    next please
    cam test voltage from led connector on power board ?

    #2
    Re: 55ln620v LG flash then no backlight

    as you take the LCD apart, you can start your LG with out Panel, then with eyes at start up you will find that one or more LED wont light on. this best way to you narrow which LED Fault at start up

    Comment


      #3
      Re: 55ln620v LG flash then no backlight

      test the leds
      check the connectors sometimes these go faulty, hard wire connectors..

      if any failing led found
      best to buy a full set of new strips.

      Comment


        #4
        Re: 55ln620v LG flash then no backlight

        You need to upload good clear pictures of the whole backside of the TV showing all the boards and also good clear straight shot of the top and bottom side of the power supply/LED driver 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


          #5
          Re: 55ln620v LG flash then no backlight

          hi all I've tested all the leds I've even swapped power supply with a known working one and logo flashes then no light so I'm thinking main board
          is there a fix for the main board

          thanks I'll upload voltages soon

          Comment


            #6
            Re: 55ln620v LG flash then no backlight

            hi there just an update
            led+ volts shoot to 125v dropping to 82
            led- volts shoot to 42v dropping to 5v
            same for the other 2 + /-
            both same on two power boards
            all leds light with tester even individualy

            Comment


              #7
              Re: 55ln620v LG flash then no backlight

              Jump all the connectors directly with wire

              is not an issue with mainboard.

              Comment


                #8
                Re: 55ln620v LG flash then no backlight

                which connectors mate thanks

                Comment


                  #9
                  Re: 55ln620v LG flash then no backlight

                  where the 2 strips connect together hard wire those.

                  and also maybe the whole wiring harness

                  its either an issue with the wiring
                  or a failing led that is not showing up with the led tester as its not supply enough current.

                  Comment


                    #10
                    Re: 55ln620v LG flash then no backlight

                    Can you verify the model number of 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


                      #11
                      Re: 55ln620v LG flash then no backlight

                      yes it's LG 55la620v

                      Comment


                        #12
                        Re: 55ln620v LG flash then no backlight

                        bottom 3 rows flash top 4 don't
                        I've checked all condunity for all connectors and test good
                        could it still be faulty?

                        Comment


                          #13
                          Re: 55ln620v LG flash then no backlight

                          check resistance between all points.
                          look for any with high resistance


                          and u have tested all leds and they have tested good ? thats correct yeh ?

                          Comment

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