Apparently there is a fix that will reduce the noise, though I haven't had the repair done to my receiver yet. I did send it back for service (Marantz is distributed by a company called Lenbrook up here in Canada) and they sent it back saying they couldn't find anything wrong. I now have to contact them to make sure they know about the repair Marantz USA has for the 7300 and send it in again. Taking into account all of the stories I've read from other 7300 owners, customer service from Marantz (and Lenbrook in my case) has been weak.
Check these links for some additional posts on the 7300:
AVS Forum
Home Theater Spot
