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LG 50LN5750-UH horizontal lines

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    LG 50LN5750-UH horizontal lines

    Hi,
    I have this TV here from a friend and it's got some horizontal lines showing for about 2 seconds - picture is fine for about 3 seconds and so on.

    no inputs are used - just power on and it does this constantly.

    I got told it would be the t-con board, but that isn't the case.

    I'm guessing it has something to do with the power supply board.

    any help is appreciated,

    cheers
    Attached Files

    #2
    Re: LG 50LN5750-UH horizontal lines

    Looks like another bad panel to me I'm afraid....

    One of the tabs--probably on the small chips at the side edges has probably failed.
    TELEFIX

    How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
    http://www.irf.com/technical-info/appnotes/an-1088.pdf
    PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!

    Comment


      #3
      Re: LG 50LN5750-UH horizontal lines

      damn, not the answer i was hoping for.

      Thx for your input.

      Comment


        #4
        Re: LG 50LN5750-UH horizontal lines

        Well, this is going from right to left, chances are it is screen failure though. Only way to tell is to enter the service menu but I think newer LG panels you have to have the Service Menu commander remote to enter the SM.

        Comment


          #5
          Re: LG 50LN5750-UH horizontal lines

          I tried to get into the service menu by holding down the menu button on the TV and the remote simultaneously as explained in 1 of the stickies here, without any luck.

          Also, I just checked the picture in the main menu. It's not those lines only.
          -When the lines show up the lower part of the screen is shaking-
          Last edited by Iceman_GER; 03-17-2015, 12:45 PM.

          Comment


            #6
            Re: LG 50LN5750-UH horizontal lines

            Have you taken it apart yet?

            Comment


              #7
              Re: LG 50LN5750-UH horizontal lines

              kind of. back panel is off. changed the t-con bought at shopjimmy. inspected the power supply board for bad caps, and that's about it for now.

              Comment


                #8
                Re: LG 50LN5750-UH horizontal lines

                have you disconnected one side of the T-con going to the panel and see if the lines persist?

                Comment


                  #9
                  Re: LG 50LN5750-UH horizontal lines

                  1 half of the screen get's vertical lines when i disconnect a ribbon cable

                  Comment


                    #10
                    Re: LG 50LN5750-UH horizontal lines

                    reverse it and see.

                    Comment


                      #11
                      Re: LG 50LN5750-UH horizontal lines

                      Oh and photo would help too!

                      Comment


                        #12
                        Re: LG 50LN5750-UH horizontal lines

                        Oh--and be careful pulling those ribbons and re-seating/swapping round--Only do when the set is switched OFF...

                        Its possible to stuff up either a T-Con and or the panel itself if done while powered up....
                        TELEFIX

                        How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
                        http://www.irf.com/technical-info/appnotes/an-1088.pdf
                        PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!

                        Comment


                          #13
                          Re: LG 50LN5750-UH horizontal lines

                          1 side at a time diconnected
                          Attached Files

                          Comment


                            #14
                            Re: LG 50LN5750-UH horizontal lines

                            Connect both ribbons again, and take a photo with a source attached to the TV that displays a bright picture preferably a solid white/green/blue.

                            Horizontal lines is a rare fault on a LCD/LED (possible).

                            Only thing left to do is to break down the panel and check the TFT boards that connect directly to the Panel.

                            Comment


                              #15
                              Re: LG 50LN5750-UH horizontal lines

                              Horizontal lines is usually gate driver failure, it happens. Now the modern panels integrate the gate driver on the panel ("Gate in Panel") they are more reliable (which is odd... usually technology seems to get less reliable as time goes on...!)
                              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                              Comment


                                #16
                                Re: LG 50LN5750-UH horizontal lines

                                Originally posted by tom66 View Post
                                Horizontal lines is usually gate driver failure, it happens. Now the modern panels integrate the gate driver on the panel ("Gate in Panel") they are more reliable (which is odd... usually technology seems to get less reliable as time goes on...!)
                                Heh, I havent touched a LCD/LED in months! When did they start doing the GIP, are those the little flaps on the far left and right of the LCD glass itself?

                                I have been doing all Plasma for the most part :P Been a blast, and to think in the beginning I was the other way around!

                                As soon as I get the parts back from ModUSlink for the VT30 thats my last Plasma needing repair.

                                I have a UN46 LED thats doing some silly stuff once the VT is done I will get that sucker on the bench and out.

                                Comment


                                  #17
                                  Re: LG 50LN5750-UH horizontal lines

                                  Originally posted by Shinju View Post
                                  Heh, I havent touched a LCD/LED in months! When did they start doing the GIP, are those the little flaps on the far left and right of the LCD glass itself?
                                  Actually the opposite. That's the older type where the gate drivers are outside of the panel. Tear down a new panel now and you won't find them, as the little gate ICs are built into the display panel itself. This, theoretically makes it more reliable as there's no tab bonding to fail (though the gate bonds rarely failed, it was more the source ones, every little helps...)

                                  Originally posted by Shinju View Post
                                  I have been doing all Plasma for the most part :P Been a blast, and to think in the beginning I was the other way around!
                                  Don't stop. You won't regret it. I fix a lot of LCDs but definitely prefer fixing plasmas. Not only does the end result look better in most cases but plasmas seem easier to fix, once you know what to look for and test. Bad LCD panels have made me very wary of picking up new LED-backlit LCD TVs...
                                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                  Comment


                                    #18
                                    Re: LG 50LN5750-UH horizontal lines

                                    here are 2 pix with DVD for input. 1 pix with the lines, the other without
                                    Attached Files

                                    Comment


                                      #19
                                      Re: LG 50LN5750-UH horizontal lines

                                      So the lines to away after it warms up?

                                      Yeah it's probably a bad panel, I would just run it till it dies.

                                      Comment


                                        #20
                                        Re: LG 50LN5750-UH horizontal lines

                                        little video

                                        no, it is not constant - 2 seconds the picture is fine - next 2 seconds it's got lines and the bottom half of the screen is flickering/shaking

                                        I have the feeling something is not getting full power.
                                        Attached Files
                                        Last edited by Iceman_GER; 03-17-2015, 05:11 PM.

                                        Comment

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