Hey Don,
When I first got my denon, i had the same problem. I used a 120 volt fan off of the SCR cooling fins in an old VFD (variable frequency drive) from work. They could probably be bought at any electrical wholesaler in your area. It shouldn't be that expensive.
You might even be able to find an "old" one at your work. ( there's probably alot of electronics on a plane.)
But once I set up my entertainment stand, I got rid of the fan. I have 6 inches of clearance on top and one on either side and have not had any problems since. I used to have the dvd player almost right on top of the denon.
If a new unit isn't an option, how about putting the receiver on top? If you're anything like me.... turning it DOWN is NOT an option!
good luck
