I am having a problem with only several channels on my Comcast lineup: Science, Investigation, Military, Planet Green and BBC. Apparently, no one at Comcast can figure this out. I had one call from Repair saying they knew what it was and they were able to apply the fix from the end. However, the channels went from black to a picture with sound but pixels. Does anyone have any idea what is going on? If they send out Tech Support, they told me it will cost me $25.