:( Comcast said they'd send a signal and that it would probably fix the issue. However, the "signals were backed up", so I'd have to hang up and call back after it got through. I waited 30min on hold the first time, this time I'm getting a call back. Error code 161-4 makes me sad. The cable card conditional access screens say "Auth: unknown". I'm thinking that's bad. I'm now authorized, but still don't get my channels.

The customer service rep said that this shouldn't have happened unless I've had a power outage or something funky recently, which I haven't. I can't believe both cards would die at the same time.

[Update]: After roughly three hours of back and forth, the final answer from Comcast is that Sunnyvale is being "rebuilt", so channels are intermittent. This will be going on for a number of months, and that I am apparently paying a reduced rate until then. Really? $83 for partially working cable is a reduced rate? Damn. I called back to speak to billing, who said they'll probably credit Sunnyvale customers at a later date. The best I could do today was to save $15 by removing HBO from my lineup.