Old unserviceable fans work well if relubricated, provided they did not have power applied for long whilst they did not turn. Then the little SRBP board inside goes black and brittle, and the windings burn out. I have some that have had this done a few times ( where can I get a replacement fan for a Slot 1 adaptor anyhow, original is designed as part of heatsink) and each time they run for another year or two before needing cleaning and relubricating again. I have 2 PABST 48 VAC fans from old Siemens TELEX machines that will run forever, as they can be easily stripped and are designed for cleaning and oiling.