I live in Houston Texas and Comcast is changing from Motorola Cablecards to Scientific Atlanta cable cards. I have a Series 3 Tivo HD recorder and a Tivo HD recorder. When I installed the new S.A. Cablecard in the Tivo HD recorder, Comcast Tech support sent a signal to my one Multi card and it activated with no problem. However the Series 3 recorder had problems. It did not activate when the signal was sent to cablecard 1 and cablecard 2. Restarting the Series 3 did not do any good. After several conversations with Comcast tech support, they did not have any answers. I decided to go through "Guided Setup" and "Bingo" all my HBO, Showtime and HD tier channels popped right in . If anyone in Houston is having the same problem with your Series 3 recorder, make sure Comcast has sent the activation signal to your cards and then go through "Guided Setup". It worked for me. Guided setup can take from 30 to 45 minutes depending on if you have a broadband connection to the Internet. If you are connected through the phone line it could take longer