When a piece of equipment dies, I always try to see if I can repair it, and if not, disassemble it as thoroughly as possible. We got this heater second-hand a few years ago, and I had the idea to pre-heat the infrared sauna with it, which worked brilliantly.
Obviously the second time it overheated, but peering into it I could find no sign of a fuse, so moved onto phase II.
Long story short: the fuse is very well concealed, and NOT designed to be serviceable. The two motors and the heating element still work just fine, so maybe I’ll look into temperature controllers at dx.com if I ever need to heat a chicken incubator.