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    Lg 50ps3000

    Hi Guys

    My 50" LG Plasma recently started playing up. Having tried my luck with it and getting no-where I've decided to turn to this forum for help.

    The TV is 5 years old and about a month ago, decided to start turning itself off. It went into a repair shop and stayed there for 2 weeks. They returned it saying they were unable to replicate any faults.

    After being fine for about a week(it never turned off), it developed a new fault. This time we lost the left 3rd of the screen to multi coloured lines (bars) filling the screen from top to bottom. I opened the TV and tried to find the fault myself. This is the view inside

    Initial appearance looked fine (nothing burnt or blown, no exploded caps). I dusted everything off then tried finding the problem. I found a video on YouTube saying to look for bad connections, and another suggesting to find dry solder joins. Found that if I bent the logic board a bit, it interrupted the lines on screen. Being a complete novice, I followed a cable from the logic board down to a screen buffer. It seemed logical that the buffer board which was directly behind the lines on the screen, must have had something to do with causing it. So I proceeded to purchase a 2nd hand logic board (Eax54875301) and buffer (EAX54872201) from eBay. When they arrived, I eagerly fitted the logic board. This made no difference and still had lines on the screen. Then fitted the buffer and still the screen had lines. Completely baffled and frustrated, I started messing with anything possible while the TV was on to see whether I could affect the lines. When I came to the AV board, I was able to make the lines go away and produce picture again. Only, instead of filling the screen with picture, I was missing about 4" picture from the left. (2" Black and 2" wrong colour) Here's an Example

    Someone has told me, that because i seen lines similar to the lines below, that the Plasma Screen itself is faulting and it wouldn't be economical to repair. Is this true? (The lines have gone away)

    I found a replacement AV board, and the person selling it advised me that my problem was the YSUS Board which was faulting, and there was no need to buy a AV board. Can anybody verify this ? Is there anyway I can test either?

    Further Research suggested checking the ribbons on the buffer boards.
    I proceeded to remove the end ribbon on the affected side and now instead of having a 4" problem ... I only have a 2" problem

    I'm now at a point where I'm not sure whether its the Screen, a buffer, the AV board or YSUS board.

    If you are by any chance able to help me figure out what the problem is, or how I could further troubleshoot my beast, I would be forever grateful

    Thanks a stack
    Last edited by victimist; 10-18-2014, 11:19 AM. Reason: Title

    #2
    Re: Lg 50ps3000

    Hmm--

    So, At various times, It can be said that the whole screen is displaying a Correct Picture--Just Not All the screen--At the Same Time.....?

    Doubt its the panel--but possible, and definitely not the Y-SUS.

    Could well be Control-Board or the ribbon-connections to the bottom buffer-boards..... The Screen tabs have chips on them--If one has failed, then its curtains for the set.
    Most probably you didnt seat the tabs from screen to bottom buffer on the far-left, they can be difficult and are very delicate, ANY damage to them is unrepairable.......

    --Try re-seating the ribbons from the Control-Board to the Bottom Buffer-Boards. No need to bother with the Y-SUS or the side buffers--they appear OK....
    Last edited by Alastair E; 10-18-2014, 11:30 AM.
    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 50ps3000

      Thanks so much for your interest Alastair

      The faults have all been pretty static in their behaviour.

      I found when I disconnected the end ribbon from the buffer, the grainy red line goes clear and the black line becomes "return of the ants". Do you think it could be the chip on the ribbon? Also are you able to confirm whether the line could be created by any ribbon or can it only be created by the ribbon directly below the line on the screen?

      Think ill try having another go at reseating the ribbons.

      Would the Control-Board be the AV board (Bottom Right) or Logic Board (Middle)?

      Comment


        #4
        Re: Lg 50ps3000

        OK so I carefully went over each ribbon disconnecting cleaning then reconnecting.

        Turned it on after and now I have a 3rd of the screen missing again (except where i had colour bars before, i now have white & black). It seems to be affecting the entire section of screen which is managed by the Right buffer board.

        Here is what i see:


        I disconnected the ribbon between the control board and buffer and this is what it produces (Ribbons between buffer and Screen were still connected)

        Comment


          #5
          Re: Lg 50ps3000

          That looks exactly like a bad panel. Did you reseat the connectors while it was powered on, or very shortly after?
          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


            #6
            Re: Lg 50ps3000

            I don't mess with it while its powered on, but I most definitely tried reseating it again soon after I found it like that.

            Panel a Buffer? Or the actual Plasma Panel?
            Last edited by victimist; 10-18-2014, 02:39 PM.

            Comment


              #7
              Re: Lg 50ps3000

              No, panel as in the screen itself... Sorry!
              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


                #8
                Re: Lg 50ps3000

                Awesome thanks for your help guys! Really appreciate it.

                Comment

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