I'm having an issue with my KS7000 TV (aka KS8000 in the US): in the middle of watching a program, the screen flashed green and then turned off. It will not turn back on again. It power-cycles as follows: Red power light will come on for a few seconds, red light will then turn off, screen backlight will flash on for a second, backlight will then turn off, and then the red light will come back on (and the cycle then repeats).
I have tried all troubleshooting steps on the Samsung website, including leaving the power off for a long time.
It appears that this is a known/common issue with the screens on this series of SUHD TVs.
It seems the only way this can be solved is by replacing the screen. However, I'm out of warranty as Samsung only issue 12 months with their TVs. I've had this TV for 2.5 years, but would expect a lot more use from it - I splashed out on this model thinking I was buying a premium product that would future-proof me for at least 7 years.