Vertical bar on Daewoo Plasma screen

I am getting a vertical black bar on my Daewoo Plasma screen which comes and goes.
We have a 46" LG plasma, with vertical lines in a variety of colors: red, blue, orange, green, you name it. We have 3 lines on the right and 1 on the left. Please help!
(Note: it's actually TH-42PX6U, not 60U.) About 20 months after connecting my Panasonic 42" plasma, I got a persistent vertical black bar with a narrow (1-2 pixel) strip of rainbow color in the middle of that; this bar is just right of center. Panasonic said "sorry, out of warranty, try this local repair shop"; they did all the diagnostics, replaced the one board that it might be (no fix) and concluded it's the ($2000 to replace) plasma panel. (Major kudos to DTR Technologies in Denver, the local repair shop, for only charging me the base $90 service call fee since they failed to correct the problem.) My TV probably has less than 200 and definitely less than 300 hours total; we just don't watch that much TV. I'm quite disappointed - and will appreciate any advice - esp. if anyone has been successful in getting Panasonic to pay attention and address this obvious manufacturing defect.
We have a very similar problem. We have a panasonic that keeps getting a black bar in the upper portion of the screen. This bar comes and goes and fills the entire screen (50") and it's about 9inches thick. We can see the rest of the screen no problem and can hear everything just fine. Anyone have any ideas? We've called Panasonic and of course were told to take it to a repair shop as it just went out of warranty about 1 month ago. I have to say, Panasonic's customer service is horrible and now I'm not sure about their products either. This tv is only a year old and cost a lot of money. It shouldn't be having a problem. Thanks again for any suggestions or help.