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.
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.
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