I've just acquired an Slingbox Pro HD refurbished on Amazon (because it's the only one supporting coaxial cable); I've set it up, cables are ok. At the Setup (using Safari on a Mac) the system detects video signal on the coaxial channel; I see and hear the preview so everything seems fine at (3) video source. When I hit next and go to (4) test remote, the preview screen becomes black. I can still hear audio but no video appears on the screen; I can change channels and it works (audio only). If I try to restart the setup, not I can't see the video on (3) unless I do a hard reset. If I continue with the setup as if everything is right, I can't see the video on any player but I hear audio (Chrome, Safari or iPhone player). Any ideas?