Samsung Plasma -- PN64D7000 Intermittent black line across screen

[catalyst6]

Hi all,

I'm experiencing some issues with my 2.5 year old Samsung Plasma. A few weeks back, a black line appeared about 1/3 way down my screen. The black line is intermittent, it seems to only appear on predominately bright screens or uniform bright screens. If there is any significant portion of dark areas in the given image in the area of the line, the line is almost unnoticeable.

It appears on TV menus and shows up regardless of input. I've read about the possibility of a bad Y-buffer board, so I went ahead and swapped the upper board, but no fix. The only notable observation from that swap was upon powering-on the tv I saw a brief white line flash in the exact area where the black line normally is. This was on the boot-up screen. I've yet to see it since.

Is this just a case of a panel failure, or is there anything else I can swap? The intermittency of the issue is really bugging me. It seems strange for a whole row of pixels to fail and only for a certain brightness range.

I'd be very grateful if anyone could offer some advice on next steps. Thanks!

[catalyst6]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

Sorry, I also meant to add in my original post that the line is usually very "sparkly." It's not like a solid black line. It looks kind of ghosty and the pixels seem to sort of flicker inside this line. It's definitely lit, but usually dark/grey on brightly colored scenes.

It stretches completely from left to right. A bright uniform skyline image would trigger the defect. If for instance, say, a dark cloud came into the frame on either side, the severity of the line would diminish.

[tom66]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

If you swapped the buffer then it probably is a panel problem. Can you supply a photo of the fault?

[catalyst6]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

Absolutely...I will upload a photo later today. Thanks for your input.

[charles frost]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

You changed the Y sus did you adj the corresponding voltages on the Y board ? there 2 small pots you have to adj the B+ that is shown on the frame inside tv. Wrong voltages could give you that look. Not the black line. Maybe a buffer is bad or, god forbid, a ribbon to screen is bad.

[catalyst6]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

You changed the Y sus did you adj the corresponding voltages on the Y board ? there 2 small pots you have to adj the B+ that is shown on the frame inside tv. Wrong voltages could give you that look. Not the black line. Maybe a buffer is bad or, god forbid, a ribbon to screen is bad.

hi charles,

I changed the upper Y-buffer...didn't touch the Y sustain. Should I be checking something on y-sus?

Edit: I've also attached a close-up pic. It's hard to capture. The line only shows on consistently solid bright or white screens. If the image were to be darker, the line would light up properly with the rest of the pixels. If a portion of the screen around the line were to become darker, the line would disappear. 2nd pic shows a gradient displayed on screen, which causes the line to disappear (other lines are artifacts from the camera).





If I set the screen to all bright green, the area of the black line becomes slightly brighter in opposite fashion.

[catalyst6]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

If you swapped the buffer then it probably is a panel problem. Can you supply a photo of the fault?

Tom -- I also saw this in your guide to fixing/troubleshooting common plasma issues:

The picture has lines going from left to right in fixed positions. The Y-buffer is faulty or the Y-driver connections are loose. In rare cases, it can be the control board. If on dark scenes the lines are lit up with the rest of the screen, then it's most likely a control board problem.

My issue seems to fit the rare case you describe. Do you think it really could be a control board issue?

[tom66]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

Not a problem with voltages. It looks like a panel issue. Since it's intermittent, maybe you can locate the cause by pushing the ribbons very gently with the handle of an insulated screwdriver. The ribbons are glued to the panel but can be removed with some effort (though I have not yet heard of someone reattaching them.)

[catalyst6]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

Thanks for the advice tom...any point in trying to replace the control board like you mentioned in your FAQ?

[tvrepairguy]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

See if any of the inverters on the buffer are cold. They should be kind of hot. Most of the time xsus is the vertical lines and ysus are horizontal lines. In plasmas you need to replace buffers and their mains together. If you dont they can short each other out

[tom66]

Re: Samsung Plasma -- PN64D7000 Intermittent black line across screen

Uh... The X-main/X-sustain has nothing to do with the vertical lines on the panel - that's the address drivers... both the X-main and Y-main drive horizontal lines. X-main drives all vertical lines & Y-main drives all lines through scan buffer board.