Mitsubishi VS-60805 Picture Loss / Convergence Boards STR...

I've a Mitsubishi VS-60805 (7yrs old) whose picture becomes distorted and eventually blacks out. When i turn the TV off and on again the picture comes back but only for 5min and than gets distorted and pitch black again. I can still hear the sounds though. anybody got manuals or knows what's wrong and how i can fix it. is it the convergence boards? if truly so where are those boards w/ STR...numbers located near/on the hotbed. and before i really dig into it what should i look for/do in order to fix them. i have decent technical experiences w/ soldering and printed boards etc but could use some troubleshooting help and manuals. thanks a lot for you advices, [email protected]