We have a bunch of Stone System 258s from 2009 which I was just looking at to see if I could figure out why they tend to randomly reboot themselves. I just noticed they have a side fan with four-pins mounted on a three-pin power connector, and a number of them were incorrectly seated so they've evidently never worked...I needed to shift them one pin over to fix. If you have any of these you might want to take a look at the Hardware Monitoring section in the BIOS to see if they're working.