I have a Zenith Model XBS444 home theater system. That was working fine with our old Zenith TV. Bought a new Dynex HDTV and can get it to work. The radio works fine and you can hear it but can't get a picture. Is there a compatibility issue or do I not have it hooked up right I have tried every way possible to hook it up then had someone else that know more then me try and they couldn't get it either.