From other threads I mentioned that I was looking at Dynamotor Whine on my DF Setup.   I swapped dynamotors and the noise with another was greatly reduced.

Reading the manual, I tested the dynamotor armature sections for shorts / opens, and it's fine.

I know I serviced this receiver dynamotor about 10 years ago, which may seem like a long time but I don't use the receiver dynamotors in the shack that often, in fact very little  I was surprised to see a lot of the grease gone so I want to add some more... and yes I know not to pack the bearings with too much grease.     

I've been using Mobile SHC 100 Synthetic Grease.

What are you using to grease dynamotor bearings?

73 Mark K3MSB