Thank you for making this post. We just got this tv yesterday and we have the exact same issue tonight. It will turn on and the video will work, and then it will cut out on its own. It repeats this process three times before finally turning off and then the red LED blinks 8 times.
I spoke with Sony customer support and their theory was that the 8 blinking lights means the tv needs a software update. The power supply issue makes much more sense as I can't fathom an engineer/programmer making a product that cuts out when a software update is needed.
Will have to make a few more phone calls tomorrow during business hours to figure out the solution. Did they repair or replace your unit?