TV Model UN55KS800
This TV is ocassionally losing HDMI sync when coming out of standby.
Removing the One Connect cable from the One Connect Box then plugging back in will fix the problem.
I think this may have started happening after the last software update as the TV was working fine for the first several months.
Is this a hardware or software issue?
This is a known issue with the latest firmware.
Here is a thread with other users having the same problems.