A few weeks ago my clear QAM channels on my basic cable stopped tuning. When I tune to them all I get is a black screen and nothing else. All of my analog channels have continued to work just fine. I thought maybe my cable company encrypted them but I went to two separate tv's and did a channel scan on them and they all still pick up the clear qam HD channels just fine? I tried changing decoders to just about everything available to no avail. Any insight you guys can give me would be greatly appreciated.