dave-
to be honest man, i really dont know the answer to that. i have never had a problem with any of my refurb purchases, so i dont know the process to get one fixed. if you have already spoke with denon, and they are gonna try and fix it, i asume that they are taking responsibilty for the unit not working, and they are not leaving it up to you and the online store you bought it from. i would think if denon is taking responsibility to fix it, then they would take responsibility to replace it if it cant be fixed.. i really aint sure, i am just guessing.. i would contact denon directly and find out what options you have, and what they will do for you.
good luck with it, and keep us informed on your process.
bigjohn