I was watching the local NBC HD @ 8:00. I wanted to change to ABC HD. The audio changed but the video went "black". No matter what channel I switched to the audio stayed on ABC. I tried my OTA channels and they had the same problem as the Dish channels. A "lost signal" error message came up and would not go away. I just got this replacement 622 about a week ago. Front pannel reset took care of the problem but I have never seen this happen before.