poking at Eurya, I saw the following: 

1) The loud fan is the front intake fan
2) the rear exhaust fan was off

I was able to get the rear fan working (switch inline on the power
cable).  I suspect the problem is the machine getting too warm and
trying to correct it with the front fan.  I expect it to improve
once the exhaust fan can do its thing.  If not, we'll need to
replace the front fan.

-Matt