oh no my tv is possessed!!! tv turns on and off on it's own?

ok i have a Proscan ps80690, chassis ctc188ae. it powers on and off on it's own for a little bit, then powers off compeltely.

i was told that these have problems in the power supply board, but he wouldn't be specific (go figure, then he'd have no reason to have his job).....

anyone have some ideas, diagrams anything?