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Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

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    Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

    Trash picked this plasma for parts and found it had some bad solder joints. It powered on after reworking most of the boards and seems like it may even work.

    The symptoms is, when showing a picture of bright (mostly white) intensity (within the affected area only) a vertical strip 2 3/4" wide will begin to fuzz out (just to the right of samsung logo, 16 3/8" from screen edge), and soon turns black (from top to bottom). Changing to a darker scene immediatley ater will cause the black stripe to fade back in (it fuzzes and clears up again) and it starts working just fine. I thought this repatability could lead to some interesting troubleshooting, as it seems this black bar issue normally doesn't come and go like this.

    More details:

    Panel voltages test OK at the test points on boards (within 1V).

    The white image which triggers the event does not need to cover the entire vertical strip (which then blacks out). Just drag a minimized white window across the vertical line at any height and within 1-5 seconds it will begin to fuzz. Remove the window from the vertical section and it returns to normal. Turning up the light output (brightness, contrast ect) makes it more prone to blacking out and sometimes the black bar will

    Initial use didnt show the black bar issue, I immediatley turned the TV brightness down when it powered on. Worked fine with white in that area (as far as I remeber). Running through the menu I selected some sort of scrolling white and black wave (that fixes pixles??). It was very bright (by default) and during this scrolling pattern I first saw some strange rainbow artifacts in the vertical strip thats affected now.

    What I think and have tried:

    The board which controls the vertical (E or F buffer Address board) has a fault or the COF ribbon has a fault. (The ribbons and board are glued so the PDP has a fault as many would say). It seems to be current/voltage/heat dependant somehow. I even tried reapplying thermal compound to the COF chips (basically removed the entire PDP) and there was no change in performance. None of the COFs had any discoloration or burns. Also, reflowed solder on the larger SM resistors on the E F buffer boards (it MAY of been worse after this, triggering black bar more easily.. MAYBE)

    I don't have enough experience troubleshooting plasmas to know if I should bother much further or where I should poke next?? SM resistors and caps on buffers? Logic main board?? Trash bin!?

    Thanks for any help.

    #2
    Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

    Any pictures of the Ysus and panel image ?
    Last edited by ReeceyBurger123; 04-13-2021, 01:53 PM.
    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/

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      #3
      Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

      The tv was not impressed by my demands for photos. Seemed worse than ever.

      I noticed and remembered some more info that might matter. The panel looked like it had mild burn in (horizontal spans at top and bottom of screen 3-4" wide each) with more of a yellow hue than the rest of the picture.

      When a black, blank, image is displayed the panel turns off (pitch black). If you bring a mouse pointer onto the screen from the left or right it will relight the panel (as if a backlight turned on). If I bring the pointer in along the bottom 3-4" of screen the panel will not relight. The mouse can be seen dimly in white, with decaying intensity and fading changing colors/pixles. If you move the mouse up (above some point along this horizontal line, around 3-4" from bottom) the panel will relight and mouse will be bright again. This does not happen if you bring it in along the top 3-4" of the panel where it also looks like it has mild burn in.....I thought that was odd

      The part of the image which looked "normal" (center portion) with no burn in to me looks noticably grainier than the top and bottom "burn in" sections (pixles fading in and out when they could be solid, kinda thing) when the TV was warming up for a very short time during picture taking.

      Phots show board and the panel mid failure, it goes solid black and sometimes black with a solid line of color or two
      Attached Files
      Last edited by JesusJones; 04-13-2021, 02:59 PM. Reason: photo exp

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        #4
        Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

        I'll add that the center photo shows more of the early failure signs (starting to fuzz out, pretty far gone already in that photo) and the right photo shows its just about to fully fail and go solid black.

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          #5
          Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

          Panels dead.
          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


            #6
            Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430

            Yea seems like it is. Bummer, i feel like that built in pixel fix program in the menu did it in by driving the screen too hard for its age/state. I swear it was working fine at moderate brightness untill that test shorted something and it started getting the black bar more and more easily.

            Live and learn

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