How do I oil an switched-mode power supply (SMPS) fan?

The SMPS fan on my old Pentium 4 box is fairly noisy of late.

A. Should the fan be oiled?

B. What precautions should be taken?

C. Where should the oil be applied?

  • A no
  • B see A
  • C nowhere at all

PSU fans are usually sealed bearing or use solid graphite lube, and I can tell you from experience that opening up a PSU can be dangerous. You could in theory replace the fan, but it's worth spending the 30 or so dollars to buy a nice new PSU, preferably with a 120 mm fan.

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You can open the PSU as long as you make sure there is NO power in it. The bearing is in the fan hub, under the sticker. Remove the plug and add a few drops of oil. However, like the other answer stated, it's better just to buy a new PSU all together; the newer units are a lot more effective.

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  • 3
    actually, no. most pc fans are sealed bearing and should not need lubrication over their lifetime. If the bearings are worn out, or there's some other damage, then there's noise. – Journeyman Geek Apr 10 '11 at 0:33
  • "NO power in it". Yes, for instance decharging all the capacitors (or at least measure the voltage), in particular the primary-side high-voltage capacitor. In order to do that, you must be absolutely sure what you are doing (so you don't electrocute yourself). – Peter Mortensen Jun 5 '14 at 12:37

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