reynola68,
Welcome to the forum.
Did the box you use have this issue prior to getting the receiver? HDMI handshakes are likely the culprit here, but it's difficult to determine if it's the cable box itself, or the pass-through on the receiver.
If you hook the cable box up directly to the television, are you receiving the same intermittent flashing?
--HDTech
My approx 6 week old 50" plasma 650 just started having a problem where the HD channels pop in and out. When I watch a standard def show everything is fine, but when I tune in an HD Channel, the picture goes black for a second or two and then comes back, but does it again every 30 seconds or so. Whenever the picture comes back on, the little window in the upper left hand corner comes back on ( it says HDMI, and lists the resolution). I can't figure out if this is my TV or my new Yamaha 663 receiver. The TV works fine when I play DVD's or PS3 games. It only happens when I watch HD Channels on cable. Please help !

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