My AM21 won't let me watch (or record) OTA channels through my HR22 any more. I've tried unplugging both ends of it several times and even did the initial setup again and still nothing. All it says it is "Tuner, Off-Air 1 (or 2, it changed after a reboot for some reason), has been removed" and a "More Info" box that says "1. Make sure external tuner is powered on." (it is, the light is on). "2. Disconnect and reconnect all cable ends between external tuner and receiver". (see above). The signal strength indicator says no signals on any channel even though I can get 2 markets (53 sub channels total) with a direct connection to the TV on the same antennas. What gives? How do I fix this?