I really only use my set-top recorder to record home movies to DVD from VHS. I cannot see why you would want to put a commercial VHS on DVD as it would still be in VHS quality.

However, I did try this on my LiteOn set-top recorder (NOT VCR combo) and by using an old VCR (must be old) and running it into the inputs it worked fine. Maybe this would work with your Emerson recorder.

The main purpose I use mine is to transfer all of those home videos. That is my purpose for using a set-top recorder. It saves me the time from transferring everything to the computer.

You could try to use an old VCR to play back the movies. It works for me through composite inputs. I've only done it once, though.