I have UA40D5000 Samsung TV and it had a Black Vignetted band a Third of the screen running across the top of the screen

SOURCE: "clouds" on 32" Samsung tv screen

My best suggestion is to replace the inverter to the lcd panel.I could look up the part number if you need.Let me know - edcarson

SOURCE: phillips plasma tv MDL 42PF9966 Black Line across screen

The ribbon cable to the drive has either came loose of the drive itself went bad. You can open up the back if you are confident and see if adjusting the cable gets the line back. If not you will need to replace the Upper Y Drive.

Thanks
Josh

SOURCE: My 50" Plasma has developed a band across the middle of the TV

I would have it looked at before saying it is burn in, a BLACK horizontal line across the set is loss of data to the display from the Y-drive panel. This is something the customer should not attempt anyway, however, if it is either the upper or lower drive board they are not that expensive. Let me know the outcome.

SOURCE: Permanent horizontal line approx. 4" from top of screen

if this line is in the picture, that is possible burn in screen. if you have a black bar at the top or faint white lines that come down from top this is caused by defective filters in vertical circuit or bad vertical output. mch

SOURCE: Black line on Panasonic Plasma

go here and follow, it will work!
http://www.avforums.com/forums/plasma-televisions/462873-black-line-fault-hyundai-hpt4240-fixed.html

enjoy!
stephen