When I turn on my Sony TV, ti stays on about 30 seconds then shuts off, What do you think is wrong?

Do a Power Reset.
1. Turn off TV.
2. Unplug the power cord of the TV from the electrical outlet.
3. Let the TV remain without power for 60 seconds.
4. Plug the power cord back into the electrical outlet. (If the television is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the television.)
5. Turn on the TV.
If issue persists after doing the steps, reset the TV to factory default settings.
1. Turn on the TV.
2. Using the supplied remote, press and hold the UP arrow button.
3. While holding the UP arrow button press the POWER button on the TV itself.
4. When the TV goes off, release the POWER and UP arrow button.
5. The TV will turn on by itself and the initial setup screen will be displayed. Just follow the on-screen prompts to finish the setup.
Sony KDL 46V5100 random shut off 15 20 sec