It's called MacroVision and some older recorders blissfully ignored it. Too bad you didn't detail what the video source was so folk could check if it had MacroVision protection.
With that out of the way, it's a bit easy to check if you had the right video output. Instead of hooking it to the recorder, connect it to some display for a test.
I just purchased a 620 dvd/vcr recorder to record off satellite. Previously had a panasonic that did it well but it finally died.
The manual is pretty useless so I put a dvd in and hit record (I selected finalize in settings). I hit RECORD and then waited for 90 minutes (a movie) but when I stopped it and played I only had audio. the screen was black.
Since it did record audio, I figure that maybe some video cables are mixed up?