Thanks everyone for responding. I did get in touch with a guy in the parts department at Marantz who agreed to send a manual through the mail. Before I started this journey (and it has been a journey), I had no idea it would be so difficult to obtain an owner's manual for this model. I'm going to scan it and have it on file just in case, though I don't plan on misplacing this one. So, if anyone else needs a copy, just let me know.
Thanks,
Rob1972