Symptoms started out as occasional blackouts when gaming. Eventually set would resync after about ten seconds. This progressed to showing a bright spot in the bottom center of the display last night. Now the set seems to be in an on/off cycle. Screen flash with a vertical green line, then Samsung logo illumnates, then power switch illuminates red.
I would be happy to look into this further. Can you please send a private message here: http://bit.ly/2Kq3B5F with the full serial number of the unit as well as what is connected to the television and how?