LG 42LN5400 led issue

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  • Troopy
    New Member
    • May 2016
    • 2
    • uk
    #1

    LG 42LN5400 led issue

    Hi all,

    Was wondering whether someone could help diagnose a problem with what looks like 2 led's on this tv

    If the backlight is set around 50% at the bottom centre 1 or 2 led's struggle to light up on/off.
    if i set 25% they dont light up at all and the display looks a bit grey at the 6 o'clock position.
    However if i set 100% backlight the leds light but this is too bright for me.
    Is this an led problem or a power issue like maybe faulty cap/board?

    Thanks
    Tags: None
    • sordids999
      Badcaps Legend
      • May 2013
      • 2152
      • uk
      #2
      Re: LG 42LN5400 led issue

      Posting pictures of the back of your tv showing the boards with clear pictures may help you more with fixing your problem

        Comment

        • Blake7
          New Member
          • Sep 2012
          • 1
          • uk
          #3
          Re: LG 42LN5400 led issue

          Hi, took some images the best i could don't have a decent camera
          Attached Files

            Comment

            • Diah
              Badcaps Legend
              • Feb 2013
              • 6376
              • Germany
              #4
              Re: LG 42LN5400 led issue

              Originally posted by Troopy
              If the backlight is set around 50% at the bottom centre 1 or 2 led's struggle to light up on/off.
              interesting fault, from the point quoted you have 3 or more LEDs Open. other could do this if the dimming IC you will find it at the bottom of PWB had bad soldering or some SMT parts related .. would be nice if you post photo of the bottom of PWB and tell IC No.

                Comment

                • ReeceyBurger123
                  Never Give Up !
                  • May 2014
                  • 7325
                  • Britain
                  #5
                  Re: LG 42LN5400 led issue

                  You possibly have a shorted Led in the screen causing the others to be dim after it due to it dropping alot of current across it. Take the screen apart and see if an Led does not light up if so replace it. Also it wont be open as if it was there would be no Bl
                  Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

                  https://www.facebook.com/Telford-Tel...7894576335359/

                    Comment

                    • Malachi
                      Badcaps Legend
                      • Dec 2015
                      • 1077
                      • Usa
                      #6
                      Re: LG 42LN5400 led issue

                      I have a set of working LEDs to this tv but may be too far to be worth while. Lol

                        Comment

                        • Diah
                          Badcaps Legend
                          • Feb 2013
                          • 6376
                          • Germany
                          #7
                          Re: LG 42LN5400 led issue

                          LED Backlight at this post are 3.3V, on LED build of one LED light and one Z-Diode in reserve way to forward current. OPEN, mean it will not light on because the contact between Z-Diode and LED light Brocken.

                          short mean Z-Diode shorted but the Light Diode will still light. in this case current will rise up which will set the protection of PWD shutdown the Backlight. if protection failed then fire will see on there

                          he still have BL dear friend ReeceyBurger123... LOL
                          Last edited by Diah; 05-31-2016, 03:25 PM.

                            Comment

                            • ReeceyBurger123
                              Never Give Up !
                              • May 2014
                              • 7325
                              • Britain
                              #8
                              Re: LG 42LN5400 led issue

                              Diah think your wrong there, Open you get no bl at all and short you will as technically the circuit can still be completed the controller wont even really notice it
                              Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

                              https://www.facebook.com/Telford-Tel...7894576335359/

                                Comment

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