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by LooseMarmoset
1301 days ago
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Those kinds of fans typically use a bronze bushing rather than a bearing. These bushings are long-lived, but eventually wear. When the bearing hole enlarges as part of the wear process, the fan rotor shaft now has additional room for lateral movement in the bearing and can oscillate in the the bearing rapidly, causing the "brrrrr" noise you hear. You can often extend the life of such bearings by adding a drop of light machine oil to the bearing (usually you have to pull off a sticker on the back of the fan to access the bearing). |
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