I am connecting my new digital cable box (scientific atlanta explorer 4200 non hd) to my sony da4es receiver via coax digital out BUT I am having problems. I have a dvd player connected to one coax input so I am using the cd coax input for the cable box. It is not playing any sound, though. Can anyone help? I went to the settings in the cable box and the coax connection is towards dolby digital. Thx in advance.