Samsung PN50A550 Plamsa Vertical and Horizontal lines

[canadaboy25]

Hey everyone,

I have a Samsung PN50A550 plasma with a bunch of vertical lines and a couple black horizontal lines/bars.

I set the TV up to run the test pattern and all of the lines are still there. The TV also power cycles. It will show the white, red, and green patterns and then powers off and back on shortly after showing the blue pattern.

I doubt all of the panel drivers and a few buffer ICs would've gone bad all at once, so that leaves the logic board.

Can anyone verify my diagnosis? I would hate to buy a logic board and have it not be the problem.

Also, the only logic boards I can find online have the same part number, but a different board number and revision number. Will this cause me any problems or will it still work fine.

[canadaboy25]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

Bump

[canadaboy25]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

I guess the next question is, does anyone know where I can even buy this board? The only one listed on ebay has the LVDS connector mounted in the right angle position instead of the vertical position so I would not be able to use it anyways.

I'm not sure what part of the board causes this problem. Bad solder joints on the BGA chip?

[R_J]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

I just got rid of a PN50A450P that had 6 black lines near the top and the problem was the panel itself, but the picture was fine other than the lines.

[canadaboy25]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

I just got rid of a PN50A450P that had 6 black lines near the top and the problem was the panel itself, but the picture was fine other than the lines.

How do horizontal lines indicate a panel failure? Doesn't that usually indicate a buffer board problem? What part of the plasma panel actually fails to give horizontal lines? I know the COF chips on the panel flex cables can cause vertical lines when they fail but the horizontal connections don't have these chips.

It seems strange to me that it would be a panel failure as it all happened at once. The only common link between the vertical and horizontal lines would be the logic board wouldn't it?

[R_J]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

How do horizontal lines indicate a panel failure? Doesn't that usually indicate a buffer board problem? What part of the plasma panel actually fails to give horizontal lines? I know the COF chips on the panel flex cables can cause vertical lines when they fail but the horizontal connections don't have these chips.

It seems strange to me that it would be a panel failure as it all happened at once. The only common link between the vertical and horizontal lines would be the logic board wouldn't it?

I scoped the buffer outputs and there was signal going to the panel on all the blank lines, This panel originally only had 2 black lines and over time it became 6 (I tried a different buffer board just to be sure) I had seen this before, I suspect the internal connection between the foil and internal element breaks . But maybe yours is different.

[canadaboy25]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

I scoped the buffer outputs and there was signal going to the panel on all the blank lines, This panel originally only had 2 black lines and over time it became 6 (I tried a different buffer board just to be sure) I had seen this before, I suspect the internal connection between the foil and internal element breaks . But maybe yours is different.

Hmm, that's a shame. I probed the ribbon cable going to the x driver boards from the logic board and a couple of the lines has no LVDS signals on them. I think that is what is causing the vertical lines but I can't be sure.

[steveh_131]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

Did you ever solve this? I have the same issue.

[canadaboy25]

Re: Samsung PN50A550 Plamsa Vertical and Horizontal lines

Did you ever solve this? I have the same issue.

No, I haven't. I am building a logic analyzer to record the LVDS signals going to and coming from the logic board to try and decipher the signal format they are using and see if the logic board is at fault.

I will post an update if I find anything out.