Tv won't stay on

You need to disconnect the power from this tv, then press and hold the power button down for 15 seconds to drain the charge off the circuit boards inside. Then plug it back in and start over. If this does not solve the problem you may need to have it checked out by a repairman. You should still be under warranty so report the problem and file a warranty claim.

plz give me the ans

Try unplugging your television for a half an hour or so. It might reset to original settings, Your problem might be input lock features. If you can get to the menu after unplugging your tv for awhile we might be on the right track. I'm just looking thru a Toshiba manual that I have.

Someone is going to have to go inside and check voltages and other things --no brand or model is indicated here so this is as much as I can suggest.

Quite possibly one of the heat sinks has come loose or a power supply cooling fan has failed.
Have you tried blowing it out using canned air?

does the power light flash three times slowly then stay off? If so chances are its just the CP150, cp120 and CP114 capacitors. There is the RCA repair kit by that same name available from www.tvrepairworld.com which has the capacitors and the CD with repair instructions

I hope that you can use the warrantee.

Otherwize, it must be possible to repair it with a fried comfortable with electronic because the problem is not permanent. This kind of problem is usually an old capacitor or a bad connection (soldering).
It would be important to check if changing the ambiant temperature fixes the problem. (I.E. move it to the seller for 2h and try..)

Regards,

Sounds like high voltage power supply has gone bad. You can try purchasing new PS online and replacing yourself if handy or you will need to bring in for service.