p.j.,
Beaver 53 sounds like he has 'been there, done that'. A full field output test on these generators involves grounding the field wire temporarily. I wonder if your external wiring could have a break or worn spot in it that was grounding and telling the generator to go nuts.
I would think you would see any generator output on your ammeter if this were the case. Maybe you could inspect all your generator to regulator wiring for defects, replace both brush holder springs with new ones and give the thing another try.
This is a great learning experience, too bad it has to be at your expense.
Stuart
