After having Tivo make sputtering and partial recordings of a number of shows, I thought it was my S3 hard drive. I disconnected the external drive, but it still happened. I ran Kickstart 54, and everything passed. Now on some of the channels I have wanted to record, I am seeing that there is "no signal." DVR diagnostics shows "-" instead of a number. The same is true on the SD channels for the same stations. It does this on either tuner and either cablecard. Thoughts?