I bought a Harman Kardon 525 (refurb) about a month and a half ago. The sound has been very good. It has produced a kind of pastic, burning smell. I called an HK service center and they said it was pretty normal when new. It still has the smell however and I've never noticed the fan come on. Can anyone tell me if the fan comes on under a certain temp or volume? I've tried turning up the volume etc. and can't seem to get it to come on. I've almost decided to take it in and get it looked at.