I had similar problem, had to replace some of the capacitors inside the TV to get it to stop clicking and switch on properly, it now switches on first time but I get the 'not available' message when trying to get to DTV. always HDMI 3 is no longer on the list to choose :-(
Contact samsung directly as seemingly they can get you the parts to replace it as this is a known fault
Darren Scordecchia, January 2011