40 inch Mitsubishi LCD TV, model LT-40134-colored vertical lines

If you wish to get some details; check the site linked here. Viewing it in "Mosaic" will make surf easy.
http://electronicshelponline.blogspot.com/
Screen shots to defective panels to LCD TVs are given. You can see and compare it to that of your TVs'

Your panel is bad. Not cost effective to replace.

I am sorry to say, but your panel is defective. It would not be cost effective to replace.

Your diagnosis is correct.

Tcon board

I've got the same TV with the same problem. Sometimes by moving it on the stand the lines will go away but it only sometimes temporarily fixes the problem. For a while it seemed like it needed to heat up to go away but that is not the case. It seems like there is a bad connection somewhere but i cant seem to find it. One day, one thing will fix it, then the next day it wont do the trick. It gets very irritating.

http://www.mitsubishi-tv.com/support.html
click warranties...
Important Warranty Announcement for LCD TV Owners

yeah get a new tv, and not a mitsubishi, they all seem to have the same prob over time. the lines mean that your picture is on its way out

I assume your Misubishi is not close to anything electrical. However, it sounds like you have had an interference for some time. This will ineviteably cause the HDTV LCD to collapse. LCD's don't respond well close to heat. Is there a vent close? LCD's do well in a properly vented area but with all this said.......they will pick up interference from anything electrical. A few questions to ask ones self........are there any wireless devices or chargers close to the LCD? Might there be an oven, a/c unit or other wiring with 220 volts anywhere close to the LCD such as in the wall?
The Mitsubishi LT is a very reliable, multi component ready set that allows great viewing with surround sound. However, stop and think about this interference. It is not something in the unit. It is an interference. Look hard and when you've discovered it.....you won't believe how crystal clear this set will be.
Let me know what you find...Thanks for using Fixya and add any comments that may help us help you.

Similar problem with an eleven and a half month old LT-40148. Approx. 1 inch vertical banding line on left side of screen on all inputs. After about two weeks, same problem on the right side of the screen.

Fortunately this occurred two weeks prior to the one year warranty expiring.

Called Mits customer service and they referred me to an authorized service center who I happened to have dealt with before.

They picked up the set. The front panel (LCD screen ) had to be replaced. Set was gone for two weeks as parts were not in stock. There was no charge. I hope this screen last more than a year.