On 25 May 2015 at 20:54, J Mcvey via ARC5 wrote: > Is it the dynamotor or are my NOS caps not so NOS? Also, there are at least three capacitors inside the end-bells of the dynamotor. As I remember it, there are two on one end connected from each brush to "ground" and one across the other end. If any of those are leaky, hum will be stronger. Ken W7EKB