I just connected a new Apple TV to my home theater. The connection is made via HDMI to my Anthem AVR-50 pre-amp. When booting up the ATV, I briefly see the Apple logo. However, once boot up has completed, all I see is a blank screen (sometimes black, other times red). When the ATV is on, I can see that it is a device connected to my network (shows up when looking at connected MAC addresses via Airport Utility). Any ideas? Thanks in advance.