My Mitsubishi TV turns on and then turns off, works for few hours,sometimes for several hours and then tuns on and off

The lamp probably needs replacing. You should also make sure that any inner fans are working properly.

The rolling is a bad filter capacitor on the signal board in the set---Any Mitsubishi dealer can look the model up and see known faults including this one---some of the sets when cold---vertical jitter in picture or just menu---If the menu is stable you have a tiny bad cap= weak caps when cold act up and when get hot regain capacitance and start to work.

Set the off timer to a longer period.IT sounds like you have the sleep timer on.If you do not change channels for mabe 1 hour the tv will automatically tun off

There is a good chance your TV has a bad capacitor or several bad capacitors. Check into getting a new Power Supply Board.

Get the projection bulb checked if fine its something internal in your tv but i think you need new bulb

This model series had a odd problem that caused this. It was the Hoizonal wire connctors for the yoke. If my memory serves me right, the Yoke wire harness went from Yoke to Yoke and plugged in at the casing of each yoke. What I found is the solder connection on the small board of each Yoke was intermitent. Please be careful if you choose to tackle this. It is in a HV Area.
Hope this helps,
Skyassoc

There are four (4) caps on the 'DM' board that need to replaced. Parts: 680ufd 16 volts, orig are rated at 1,000 ufd.

you must have a wd series mitsubishi..the lamp tempurature sensor has a manufacturing problem..mitsubishi has an updated one to take care of the problem..the sensor itself is not bad it is the way the wires are crimped in the plug,,the new one is soldered..the part number is 299P313010A,

I Can Assure You That This Problem Is Associated With 2 Capicators On The Power Supply Board.
 

time for a new tuner probably about 150-200 bucks to fix