Samsung QE50Q60AAUXXU TV restarts after about 30 seconds

My TV is 2.5 years old. Yesterday it started restarting every 30 seconds. A black spot appears, like an ink stain, and get bigger and then TV restarts. If I poser down the TV for a few hours and start it up it will remain on for about 20 minutes and then it starts restarting again every 30 seconds. I replaced the HDMI cable and reseated all cables. I also checked the device for updates and there were none.