Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

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  • Dannyx
    CertifiedAxhole
    • Aug 2016
    • 3912
    • Romania

    #1

    Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

    Good day folks. I decided to "revisit" this Samsung UE40F5000 TV I've talked about in a previous thread which inexplicably died during an LED replacement. Originally, it came in with no backlight in the top portion and after replacing the dead LEDs, we put it back together and to everybody's dismay, there was no more picture AT ALL. I eventually had no choice but to conclude it's a bad panel, without having a clue as to HOW it actually died by just laying flat on the table, but anyway.......we had no choice but to buy the guy a new TV, but I was also left with the dead one, so after some time, I decided to dust it off and try and figure out what's really wrong with it, since I've learned some tricks in the meantime So this brings me to my actual topic: is it actually possible to repair a buffer board ? I concluded the left (or right, really when you look at the screen from the front) buffer board is somehow busted. Here's what happens: when the buffer is not connected to the T-con board, all the voltages on the T-con board are correct: 1.2v, VGH (35v) and VGL (-6v). However, when I plug in the buffer in question, everything on the T-con dies - 0v on all these test points. I tried probing around the buffer board, hoping to find a short, but I couldn't find any, at least not on any of the discrete, visible components. I then tried a trick I learned from some "kids" on a local repair website: placing a piece of tape over the VGH and VGL pins respectively and see which one causes the voltages to drop. It turns out it's the VGL pin that does this, because when it's not making contact with the t-con board, but the VGH one is, all the voltages stay up and there's even picture coming on screen (true, it looks very bad on the affected side, but it IS there). If I remove the tape and allow VGL to contact the T-con, the previous problem reoccurs. The image persists because there's not VGL to "discharge" the panel. The guy who came up with the idea was lucky enough to have a faulty VGH pin, so the right side of his screen didn't come on at all. I couldn't exactly trace where the VGL pin is going, but I assume it goes to that component at the end of the buffer board in the picture. Is it this thing ? Does this project have the slightest chance of success, or is it dead from the get-go ? Cheers.
    Attached Files
    Wattevah...
  • Hamie
    Badcaps Legend
    • Apr 2014
    • 1383
    • UK

    #2
    Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

    Why would you buy someone a new tv?

    Before I'd dismantle any TV to the LEDs/ccfl's I'd make them aware the complexity of the repair required and the panel may end up damaged.

    If they are not happy with that then they can take it somewhere else.

    They've brought in a broken tv all you've done is make it more broken.

    Comment

    • ReeceyBurger123
      Never Give Up !
      • May 2014
      • 7325
      • Britain

      #3
      Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

      Originally posted by Hamie
      Why would you buy someone a new tv?

      Before I'd dismantle any TV to the LEDs/ccfl's I'd make them aware the complexity of the repair required and the panel may end up damaged.

      If they are not happy with that then they can take it somewhere else.

      They've brought in a broken tv all you've done is make it more broken.
      I had to do the same 60" got smashed in my possession so brought another of the same spec cost £500 check my vid out on 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

      • Hamie
        Badcaps Legend
        • Apr 2014
        • 1383
        • UK

        #4
        Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

        Originally posted by ReeceyBurger123
        I had to do the same 60" got smashed in my possession so brought another of the same spec cost £500 check my vid out on it
        Not seen the video mate but im assuming the issue to repair the 60" didn't involve dismantling the tv down the leds.

        If someone gave you a plasma and you dropped it or banged it I'd understand having to fork out for a replacement.

        The point I'm trying to make is though, if you know it's a risky repair that involves removing the panel cover your back before you do it.

        Comment

        • Dannyx
          CertifiedAxhole
          • Aug 2016
          • 3912
          • Romania

          #5
          Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

          Originally posted by Hamie
          Why would you buy someone a new tv?

          Before I'd dismantle any TV to the LEDs/ccfl's I'd make them aware the complexity of the repair required and the panel may end up damaged.

          If they are not happy with that then they can take it somewhere else.

          They've brought in a broken tv all you've done is make it more broken.
          Because it was half-functional, albeit a bit dark at the top, but it somehow died completely whilst in our shop, so as shitty as it may sound, it was considered to be our fault and we had to cover the price of a similar one....end of story
          Wattevah...

          Comment

          • Dannyx
            CertifiedAxhole
            • Aug 2016
            • 3912
            • Romania

            #6
            Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

            Yeah, I didn't see Reecey's post, so I had already answered, but same story basically....
            Wattevah...

            Comment

            • vinceroger69
              Badcaps Legend
              • Mar 2012
              • 6714
              • uk

              #7
              Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

              this is the video link reece mentions im sure ive read that this has happened before on samsung plasmas
              https://www.youtube.com/watch?v=qqhrVkvC2IM

              Comment

              • ReeceyBurger123
                Never Give Up !
                • May 2014
                • 7325
                • Britain

                #8
                Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                Originally posted by Hamie
                Not seen the video mate but im assuming the issue to repair the 60" didn't involve dismantling the tv down the leds.

                If someone gave you a plasma and you dropped it or banged it I'd understand having to fork out for a replacement.

                The point I'm trying to make is though, if you know it's a risky repair that involves removing the panel cover your back before you do it.
                Lol watch this:

                https://youtu.be/qqhrVkvC2IM
                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

                • ReeceyBurger123
                  Never Give Up !
                  • May 2014
                  • 7325
                  • Britain

                  #9
                  Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                  Originally posted by vinceroger69
                  this is the video link reece mentions im sure ive read that this has happened before on samsung plasmas
                  https://www.youtube.com/watch?v=qqhrVkvC2IM
                  Cheers bud
                  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

                  • Dannyx
                    CertifiedAxhole
                    • Aug 2016
                    • 3912
                    • Romania

                    #10
                    Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                    Mine's not a plasma (fortunately ?) so the question is whether I should strip it for parts and toss out that large doorstop of a screen or try to fix it....not like I've got anything to lose by honing my electronics skills on it a bit
                    Wattevah...

                    Comment

                    • vinceroger69
                      Badcaps Legend
                      • Mar 2012
                      • 6714
                      • uk

                      #11
                      Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                      as you say if you can find where that trace where the VGL pin is going to on the panel pcb etc hopefully you can find the faulty part have you tested all the smd capacitors as saw a thread where one was causing tv to stop starting up.

                      Comment

                      • Dannyx
                        CertifiedAxhole
                        • Aug 2016
                        • 3912
                        • Romania

                        #12
                        Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                        Originally posted by vinceroger69
                        as you say if you can find where that trace where the VGL pin is going to on the panel pcb etc hopefully you can find the faulty part have you tested all the smd capacitors as saw a thread where one was causing tv to stop starting up.
                        I have tested all caps and even the diodes at the end of the buffer in the picture there and they don't read any dead-shorts, although I'm not entirely positive that they're indeed OK. I t could also be the COF itself I believe, in which case it's REALLY game over.
                        Wattevah...

                        Comment

                        • Hamie
                          Badcaps Legend
                          • Apr 2014
                          • 1383
                          • UK

                          #13
                          Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                          Originally posted by ReeceyBurger123


                          God that is unfortunate.

                          Comment

                          • ReeceyBurger123
                            Never Give Up !
                            • May 2014
                            • 7325
                            • Britain

                            #14
                            Re: Repairing a Samsung buffer board - possible ? (image persistance, VGL pin fault)

                            Originally posted by Hamie


                            God that is unfortunate.
                            Me all over
                            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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