The last thing I did was remove both reverser fingers and clean them and make sure they were touching the contact surfaces. With the fingers out of the way I could also clean the drum better. No difference. As far as the armature goes, it turns very freely in both directions. I wish I had another 5-wire tender but this is the first American Flyer project I've taken on so I don't have any. Thanks for all your suggestions!
John T.