Sets of that age suffer terribly from leaky electrolytic capacitors and dry joints. Mitsubishi TV power supplies of that era are certainly prone to it. The syptoms are too general to really be specific, as many faults could cause the set to shut down. Although, I believe C916, C906 were favorites.
(Power supply holds a large amount of energy for several hours after switching off).
Cobweb
June 2005