Digital TV Toshiba 2999UXC

mime toshiba TV 2999UXC had broblem. When I set on, picture normal within 3 min and then screen pulls in from both sides and blur, screen flicker and disappear, see black screen but with audio. Does any one have any idea what the problem could be? I should be gratefull if you woud give me electric diagram or service manual.

thanks & best regards