Have just bought a Harmon Kardon AV255 amp and am having major problems getting the Apple Tv to work with it. The signal seems to come and go and only works for a sustained period when I restart the ATV! As soon as I change the source on the Amp I lose the ATV. I am currently connecting using HDMI and am thinking of trying component instead, but would prefer to stick with HDMI. Anyone got any ideas?