Thought I'd put this up in case anyone else runs into this situation.
Last Friday, immediately after the C133 error problem was fixed, I wound up not getting any channels other than my locals. I have two TiVOs, and everything was fine on the HD but not on the Roamio Basic. I called TiVO, who went thru the Cable Card settings with me, which showed that, for whatever reasons, it appeared that the Card was not paired correctly (the CSR did not feel it was C133-related, but I think it was very coincidental). We both then conference d with the cable dept. at Comcast, who verified the #'s, sent a couple of signals, but nothing worked. The thought was a bad Card, and suggested I swap at the local office the next day.
This morning, I removed the card, and thought...why not try re-inserting it and see what happens. Well what happened was...all the channels came thru! I called TiVO and together we checked the CableCard screen, and everything was correct. So...if something similar happens to you, try that. No clue from TiVO as to why that happened, tho he tended to blame Comcast. In any case, I'm happy (for now).