Sound but no picture?

This is a new symptom I've never seen before: ESPN HD (channel 403 here in Delray Beach, FL with comcast) has no picture, but does have sound. As near as I can tell, only that channel has the problem. Has anyone ever seen this happen before?



I'm going to reboot the TiVo when it finishes the recording it is making on a different channel and see if the picture comes back.