I had a bright red 1" wide vertical line on the right side of my Vizio P42HDE as well as an equivalent Green line on the left. Sometimes a Blue line would appear adjacent to the red line. Had this TV sinc Oct. 2005. Based on internet research, I opted to purchase an LG 6871QCH060Q board (upgrade to the 6871QCH038A and the 6871QCH038C). Picked the board up on Ebay for $100 + $10 shipping from ShopJimmy
From start to finish, this took about 2 hours to repair. Tons of screws to remove. Took me a while to figure out that the video connection unit in the back is completely modular and needs to be removed before attempting to remove the back cover. Once the cover was removed, I was surprised that I could not see where the replacement board was located. Turns out, you have to go one level deeper and remove the audio board and digital board followed by metal bracket/cover. Once removing the metal cover, the bad 6871QCH038A board was visible. A couple of zip ties will need to be cut as well as several cable connections to get to the 6871QCH038A board. Replaced the board with the 6871QCH060Q upgrade. Make sure to keep the sticky foam rubber isolation pieces and adhere them to the new board. It did take some time to figure out how to disconnect and reconnect all the various types of cable connections. Just take your time. The power cable connector for the 6871QCH060Q board is in a different location, thus I had to reroute the cable. Reassembled and only had 2 unused screws left!
TV workd great. Lines are gone. Have a little burn-in going on where the red line appeared, but still better than forking over $800 for a new 42" LCD 1080P TV. Hope to get a couple of more years out of this Vizio.
One line I found has a general example of LG/Vizio repair manual. Not exact, but close enough...http://www.scribd.com/doc/7580885/LG-TV-Plasma-Training-Manual