Goes on and off on and off permantly

Answered.

Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/

Replace the damaged capacitor and check first. If it do not help you, replace the power supply regulator board as card. It will be best, rather than trying to make the present one get repaired.

Most of the time it is the touch button assembly on the tv. The Volume down touch button switch is sticking.
I hope this helps,
Skyassoc

Need s to be replaced the main board.

I have the same problem with a 40" Toshiba LCD, Component cables work fine with FIOS but not HMDI, goes in and out then blank. HDMI with DVD player works fine. Best buy reported this same problem from users with this toshiba lcd but no solution.

Either the sleep timer is set, or the power supply unit is faulty.

go into menu look for sound click inside speakers or try to use outside speakers. i fixed 3 or 4 witk same trouble... good luck & happy 4th

TV Parts Universal TV Stands DLP Chips ShopJimmy Your T-Con board is toast. You can get another from here.

I had this problem on my 42" Philips. Just got it yesterday and worked fine on the tv stand. As soon as I mounted the TV to the wall via wall mount system, I had the exact same issue you did. Figured it out today.

The wall mount was putting pressure against the center of the back of the tv (tv set had a slightly rounded back plate, and the mount was a flat plate). As soon as I put spacers (part of the wall mount hardware set) between the wall mount braket and the tv so there was no contact except at the mounting holes, the tv worked fine.

My theory is the pressure pushed the tv back plate against some board components which caused them to overheat (no air flow); or put pressure on internal connectors. I dont know.

Hope this helps, may not apply to your situation.