Your input is set on TV ( that assumes you have an antenna ). Press input button ( or from input menu for smarter TV ) to change your input to correct HDMI or correct Wireless port whichever you are using for cable TV. This is from Samsung remote NOT Xfinity remote.

Cheers!

1. Press the Home button on remote
2. Go to Settings-General-External Device Manager
3. Set 'AnyNet' to OFF. (This allows other devices to control your TV)

if that doesn't solve the problem, try this:

1. Press the Home button on remote
2. Go to Settings-General-Network-Expert Settings
3. Set 'Turn Power on with Mobile' to OFF

Hope either of these things helps!

Is the TV setup programmed for a timer on & off ?????

Have you tried the suggestions here:

how-to-troubleshoot-the-samsung-tv-that-keeps-turning-off-by-itself/

Very strange. I read your post, I left some replies-guesses. Was watching a recorded show, we have xfinity. We went out, shut off the TV. When we returned the remote would turn the TV on, it would not boot up, it would shut itself off. HUH?

I rebooted the modem, I disconnected the power strip connected to the TV and I either fixed it or truth it fixed itself.

Far from a technical expert. I have each related device plugged into a power strip with a spike protector. To reboot it is one switch for each section.

Samsung crazy tv!
 

We bought a Samsung tv last year and it decided to turn off on it’s own. We called the company and they sent parts and repairmen to fix it. They pretty much replaced all the tv except for the case. It was still under warranty.

Just use the Xfinity remote control and put away the other remote!!

I have a Vizio that does also turns on or off as well as occasionally turning off the sound or flickering. I have spent hours researching the issues and trying the fixes I gave up. My solution to the random turning on/off is I unplug the TV and plug it in when I want to watch it.

We hired MMD to fix our problem with the TV turning itself on and off. Yeah, it is fixed! Apparently our TV was allowing other people to hook up to our TV Bluetooth. MMD deleted the ability that allowed others to do this. Thanks to everyone for their suggestions.

Wow you must have some really close neighbors.

The last Samsung TV I had would operate fine most of the time but intermittently it would not power on at all until I completely unplugged it, wait 10 or 15 seconds and then plug it back in. I went back and forth with Samsung support for 5 months before they refunded my money. They tried everything to fix it including sending a different TV, sending a repair guy from Orlando etc etc. Finally after countless hours on the phone and dealing with having to send the TV's into support centers etc etc , they just refunded the money. Personally, I will never buy a Samsung anything again.

solar flairs LOL