I'm not sure if this is a Tivo problem, or a CC problem. Maybe I can get some answers here. One of my tuners will occasionally go to SD while watching a HD channel, and the audio will have an echo. When I switch to the other tuner, then back, the picture and audio are fine. (It also records the audio/video issue if the show is being recorded.) Also, occasionally, one of the tuners, (possibly the same one, haven't gotten to that point yet,) will not show certain digital channels. It will record that channel and everything, but it just shows a black screen with no audio. CableCard? Or bad Tivo?