What are they, 1U units? The fans are loud when you "power on" but will slow/quiet down when you actually "turn it on" and boot.
The initial power on (fan loud) stage may not necessarily mean the unit is actually "on." You still need to press the "on" button (even though you already hear the banshee fans) to get it to POST and boot. The "on" button is different from the "master" power supply on/off button at the back.
Of course, if the unit doesn't work then you'll be wasting gobbs of time, so try and find out if they are indeed working. Then, open it up to make sure parts aren't missing. Good luck.
