Advertisements In South Florida w/Comcast cablecard. I have two Tivo's, both HD. The newer one about once a week or two comes up with a black screen and the message HDMI connection not permitted and I cannot receive any channels. I restart the Tivo box, once, twice or three times until I finally get the connection to work. the older HDTV Tivo box has no problems. Comcast already changed the cablecard once. Anyone have any ideas what is going on???