XenonMan and EEman -- I appreciate your thoughts that this is unlikely to be a mere transformer design issue, as I hastily speculated. I have decided to give this one last try and will exchange the 7900 instead of returning it. Also, I had an extremely helpful discussion today with ATI. cp1966 I'm sure you have already tried this, but the technician suggested gounding all components together to a common point and terminating w/a crimp connector or something similar. I have only done this with 3 of my four components, so it may work. Will report back in mid-January when I have received the new unit and completed my troubleshooting.