When my Industrial Aussie made Mistral did the same thing a couple yrs back, a friend of mine came by and, by coincidence,
happened to have designed it. He said that they had taken short cuts in assembly, and there was no proper alignment done
of the shaft and the bearings, just press fitted together. He simply "whacked" the ends of the casting, 90o to the shaft,
until it spun freely then, knowing where the bearing was, drilled a small hole to lubricate it. Finally used a small screw to plug the hole.
It's worked ever since, better than new. He's done it twice since to my fans, always perfect results.