Samsung LN-T5265F keeps turning off and on for no reason

Do you possibly have any other devices that operate at the same frequency?

I've heard crazy things like a microwave being able to an Xbox on and off.

Just a thought.

if you have not eliminated the power source as a problem you can connect something like a lamp simultaneously to the same power source as the tv to see if the light dims or goes dark

do you see the red led in the bezel bottom right corner turn on to indicate power off

the off to on effect could be a loss in signal which behaves like a loss in power or turning on and off the power button on the remote

you should try other signal sources inputs for hdmi, component, off the air antenna coax, cable tv coax to possibly isolate the cause to a signal source input

as a last resort because it seems unlikely:

the infrared sensor in the bezel bottom right corner could be covered with something soft(to avoid scratching the bezel) and non-adhesive(dont mess up your nice tv) like a pillow to prevent possible stray infrared energy from reaching the infrared sensor

you can test with your remote to insure the infrared sensor is covered

if the problem stops when the pillow is covering the infrared sensor then you may have a stray infrared energy problem

I have the same problem on my 1.5 month old Samsung FPT6374 Plasma.
While watching TV connected to a HD cable box through HDMI or Component, the TV turns off and then on its' own at random times.

So far the source of the problem has not been determined. I'm getting a Samsung technician take a look at the TV in the next week.

Has anyone found the cause?

This may sound stupid...but is it possible your neighbors have the same tv/freq and keep turinng it on and off? Or even worse..someone is doing it to you on purpose as a joke...

Oh man am I ever ready for April 1 now. A couple minutes with a learning remote at the victim's house, sneak up outside...

You don't by any chance have it plug into the "Clapper"? trying clapping a few times to see what happens. No.. maybe that gremlin in the old bugs bunny cartoons is back, check behind the tv and be ready to duck. If nothing else, next time your tv gives you a problem go out to the shed and find the biggest sledge hammer you can find and go to it, I promise you, for about a minute you will feel greeeaaatt...
Sorry, couldn't help myself. But after reading 90% of posts complaining about something, I've decide to give up buying a new flat screen for now and go to the library instead and read a good book.

I have a 422 samsung LCD qwhich is about a year and a hald old. It keeps turning off, with the red light flashing still. 90% of the time it's when we're watching TV and have changed the aerial-made no difference. Now it's started doing it when playing the PS3. Is there a fault with the TV and how long do Samsung guarantee for?
Any suggestions gratefully received!

In the case of my Samsung FPT6374 Plasma, which had the same issue, the Samsung tech sent me a USB flash drive with an updated firmware to install on my TV. This did not fix the issue for me, so I had the retailer replace my new TV with a new one. You should contact Samsung to start the troubleshooting and support process to determine how to fix the issue or determine what your options are (fix or replace, etc).

My new Samsung FPT6374 Plasma, gets used approx. 15 hours per day has been problem free for almost 4 years.

good luck