My computer power supply fan is terribly noisy when I first turn it
on. After a few minutes it quiets down and is fine till the next time
I turn on the computer. Then I go in my barn and turn on an electric
heater and the fan in there is just as noisy, but it too quiets down
once the thing is running for a few minutes. Why do these small fan
motors do that? If a bearing was bad, I dont think they would quiet
down. I just learn to live with the noise as long as the motors run.

G.T.