I did have the fuse blow, when I first got the board and I wasn't paying attention to how I was connecting everything, so the fuse was the first thing that I checked. I have version 2.0xx of the duet wifi. Since it's just the part cooling fan connector that's not working, I think I might patch the part cooling fan into the always on fan connector for now to stay operational while I wait for a new mosfet.
Of course I get this failure right after I accept an order for printing...
Also I had a serious geek out watching your youtube video about the mass-cancellation gantry that you made for your beast of a printer. I have serious machine envoy.
EDIT: looks like noctua makes a 5v and 12v variant of that same fan. Ill buy the 12v version.
Definitely the way to go. Using PWM to undervolt is not a good way to operate because the fan won't be getting 5v it will be getting 12v 40% of the time. It might not damage the board but it won't be good for the fan.