Hello, I'm servicing a Philips 42PF7320A/37. Has several wide black vertical bars on screen. They are not soild back bars but have random lines flickering in them. Would it be a bad screen,scan or sustain board or main board. It uses samung 42 HD S4.0 logic board, Etc I can send picture of problem.
snipped-for-privacy@sbcglobal.net wrote in news:1155009622.370218.102470 @p79g2000cwp.googlegroups.com:
I fix this stuff every day for a living. Doing mostly Samsung now but have seen this problem many times.
You are screwed, dude. The wide vertical bars are caused by some faulty connection from the buffer boards to the PDP (Plasma Display Panel) itself. You will see at the bottom of the set there are two or more boards where the ribbon cables from the PDP connect into little plastic snap in sockets. Now the problem could be caused by a faulty connector, ribbon not seated correctly, faulty buffer board, or bad PDP (Remember, the ribbons that go to these connectors are part of the PDP itself.).
The way we handle this as official Samsung warranty procedure is to replace the buffer board directly under the strip and then hope for the best. If the line(s) did not go away, then the PDP is bad and Samsung will replace the set.
What I have found in the field is that if the vertical bars are pure black, then you have a small shot of actually fixing them by replacing the buffer boards. If there is any kind of color in them at all or if the lines in the bar are thin, your chances are zero and the PDP would have to be replaced. This costs more than a brand new plasma set so you are pretty much SOL.
The buffer boards are what connects the vertical axis of the PDP to the circuits. The different color rows are done by the horizontally connected Y-Main board so if you get colors in the bars, it won't be the lower address buffers. If the line is black, then it could be as that means that every column in those rows are failing to turn on and yes it could be the buffer board or connectors. Theoretically, pure white might even be possible although I have not seen it because what if the buffer board to that connector was "stuck on all the time"? But colors in the vertical bars? No, bad PDP but don't take my word for it, replace the lower address buffer boards directly under the vertical bars and see for yourself.
The buffer boards are rarely defective in this way unless you can actually see that the ribbon connector itself is broken or faulty. Snapping back the holder on the ribbon socket, gently removing the ribbon, then putting the ribbon back carefully and making sure that it is seated fully and properly works just as good as changing the board. If this does not clear it up, toss the set. You ain't gonna fix it unless you want to shell out several thousand dollars for a new PDP.
Myself I pretty much hate doing this "Repair" because it is almost always a total waste of time to replace the address buffer boards, it only works on solid black bars and almost never fixes this problem, maybe 1 in ten if that. Samsung and the other manufacturers know this but will force you to replace the address buffer boards (And pay you for doing it.) before they start handing out three or more thousand dollar TV sets as an exchange. Once you replace the address buffer boards and discover "Oh gee it didn't work.", then the manufacturer will replace the set, knowing that it is a bad panel (Remember, the connecting ribbons are part of the panel.)
Sorry to give you bad news like this but you might as well hear it, see it, and then get over it quickly so that this issue does not forever consume you.
-- ~Ohmster
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