Lines in screen

Hi Andrew, try replacing the tcon board

Sound like your Y-Sustain board has one foot in the grave. The Y upper buffer and Y lower buffer boards go when the Y Sus Goes too...

Since the lines are vertical, the image is lost sideways and the corruption changes with the image then clearly this is a sign of Y-Sus failure, not the Z-Sus or the buffer boards.
An logic or input board failure would affect the entire screen, not just a part of it and a failure in one of the buffer boards would affect strictly defined lines of pixels and the defect would be constantly there all the time.
Since you haven't told us the exact model i can't point you to a replacement board.

HP-R4252 NOT LCD TV
IF LCD TV has vertical lines try cleaning T-con board to lcd panel cable or replaced t-con board

I'm not an expert, but I have determined that the vertical bars that are often red, sometimes blue ... and sometimes both ... are related to a bad control board. I've also read that a common fix is to buy a repair kit with includes the ysus, zsus and control boards ... all replaced together. My experience was that after a month or two with the 1.5" wide stripes, that you eventually loose the entire picture and have sound only. MIne comes back, but won't stay working for very long and the stripes are always there (buy used to fade and flicker sometimes). I'm planning on replacing the control board.

sounds like your deflection circuit is weak..seems a power supply issue is at hand..what documentation do you have in your possession?

never buy LG products again !

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 parts.

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

I had the same problem and fixed it by replacing the control board. It's a little nerve wracking, but required only simple hand tools. If you'd like to see detailed pictures of the repair check out my blog.

http://greenrenovation.wordpress.com/du-42px12xc-repair/

i get the same. was told i needed a new board