Hi guys, I just got my tivo HD and got my Mstream cable card from Comcast. I get the analog channels 1 thru 80 plus HD channels. But when I try to view channels 35 to 80, I get a grey screen. All the other channels work great. When I plug the cable straight into my ntsc tv tuner, I get 1 thru 80 fine. The cable is plugged into the CABLE input. I re-ran the guided setup a few times too. Any ideas?