Hello. I have a Zenith HDV420 Hi def receiver hooked up [with cable] into a 60 inch Sony 1080i-capable TV that I got 7 or so years ago. I locve the TV ans thought that getting an HD tuner for it was a good option vs. buying another set with a tuner. Anyway, running "E-Z scan" every way I can I still cannot pick up any HD channels to display on the DTV input of the set. It just says "no signal" every time I try. Any ideas? Thanks in advance for any assistance