Cave, once again we are on parralel paths oddly enough. Two weeks ago I heard a fairly loud new sound out of my atv. Knowing it wasn't the drive (eSata modded of course so there isn't one) I popped it open and uplugged the fan (such that is is). Voila, no more loud noise, in fact very quiet. So, I ran it for the rest of the week upside down with no bottom (much like when we were testing esata bridges). Ran fine, probably a bit cooler. Note, Since the top (now the bottom being upside down) is a heatsink I did place four of my kids lego's under it to give it some air.
So, I thought why not and I then removed the fan altogether and closed it back up. Running fine, top feels about the same.
So, what does this tell you about you're situtation ?? I have no clue but maybe you're wireless card has issues as its running so hot ? My card did not feel hot to the touch really when running upside down. Having said that I am synced and run ethernet to the AEB so that might be the difference. Dunno.
Anyway am now running eSata and Free Air for about a week. So far so good. Note: to anyone wondering underneath that fan is nothing but logic board, no chips. The cpu is on the *other* side of the logic board under the top (heatsink) and once out, for the life of me I can see no way that fan moves any amount of air anywhere. Its almost like a plugged system. If it moves anything it has to be very little and Anandtech I think said the same when they disassembled it. Very strange.
Back to topic: seems odd that wireless card is so hot. Maybe disconnect it and run the atv and see if it overheats ? Just tossing it out there.