Toshiba 50H82 Projection TV problem

My 5 yr-old Toshiba 50" 50H82 Projection TV has a distorted screen: There are wavy blue/green/red tones bleeding in from the left side of the screen. It started out as only 1/8 the screen, now it's halfway across. Some days it's not there at all, but it's becoming more frequent. I called a repair shop and they need $100 to just come out. The rep on the phone told me that this type of repair usually costs between $300 and up. I'm not sure if I'm ready to pay 1/3 to 1/2 the cost of purchasing a new TV. Is this a repair that can be done by a regular Joe? I really hate to toss aside such a large purchase. Thxs!