As Rush says, "Big Thank You's go around the world": thanks much to bakpakva, Humanoid1, Splotto, bweissman, miata, ihifi, brinyhenry and a few others for a discussion of XA2 fan noise issues starting around post 2672
Got the XA2 in September 2007 (a July 2007 manuf date; built in China). Last night heretofore noticeable but tolerable fan noise became a roar upon turning on the deck. Googled around and found this thread; adjusted the tightness of the screws and the noise level has returned to previous levels. Hopefully this is a semi-permanent solution but if not, thanks to ihifi, I have model number info on what to possibly replace the fan with (something I've done before on my ancient PC).