Last night Comcast came out to boost the signal for my neighborhood. After they left, I started having problems where the encrypted channels would go to the black screen. This is only a problem with the cablecards. My comcast STB continues to work fine. I can go into the Cablecard Menu and Test the channels, and everything comes in normally. If I exit out and go to regular TV watching I can now receive all the channels, but after a couple hours it goes back to the black screen. I've gone through this cycle about 4 or 5 times now. Any ideas?