I just recently purchased a Sylvania 37" LCD HDTV with a pair of HDMI Conversion cables to utililize the "Digital" DVI-D output on my Comcast HDTV box. Well, it appears that after properly connecting everything I get a picture for a few seconds and then switches to the snowy screen and back to regular picture. The HDTV has a native res of 720p and can receive 1080i. After checking the signal info on the tv via Component it tells me the picture is in 720p.
I'm assuming the problem is with the Comcast HDTV box, since the cable guy had to swap out the box on three tries. Eliminated the TV since is still has the smell of styrofoam on it.
I'll call Comcast support as a last resort just seeing what is open knowledge first.