I second the comments on bearings or magnets. I would think that bearing would be progressively louder whereas a magnet fail would be all of a sudden. Personally I’ve been using ETs since 1980 and have never experienced a brush failure or ones that were completely worn out. Take care, Dean > On Dec 1, 2021, at 10:20 PM, David Tiefenbrunn <davidtief comcast net> > wrote: > > replacement. > Dave