I have a Thomson 50" DLP Rear Projector TV, when watching after a while the picture will distort and flicker the colour turns wierd brownish, there is also a strange whirling sound from within at different frequences. Sometimes the screen goes off completely and restarts itself. Or I can trun it off wait a while and switch it back on and it is normal again, but after a while will do the same thing. Any suggetions? Thanks Carl