There were a lot of Taiwanese PC/XT, AT & tower power supplies with
sleeve-bearing fans that would seize up at any time after they were
shipped from the factory. If you were lucky, you would hear the fan
fail but they often died a silent death, taking the whole power supply
with them. If you can, find one with ball-bearing fans or replace the
sleeve bearing fan. Personally, I like the US Toyo fans. I have a
whole bunch that replaced sleeve bearing fans and are still working
fine after 20+ years, some after running 24/7 for several years.
There was a some write-up about PC/XT/AT power supply fans on
CompuServe's IBMPC forum sometime in the late 80's. Interestingly,
soon after that appeared Taiwanese power supplies, all with sleeve
bearing fans, started disappearing from retail shelves and pallets of
them, new and used, started appearing at surplus stores. For a good
while you couldn't find a new power supply with a fan with sleeve
bearings on retail shelves. And then the Chicoms started making them.
==
jd