I guess I am the only person here who _repairs_
fans. I've been known to
rewind the stator, and replace components on the control PCB.
Oh! What about the
bearings?!? That's the most usual source of failure...
Well, if they're ball races, I'll replace them (they are almost certainly
going to be a standard size). If bushes, well, I'll take a bit of phosphor
broze rod and a lathe...
Perhaps I've been lucky, but I've not had much trouble with the bearings
in the fans of _classic_ computers. Modern PCs are another story...
-tony