The output stays fixed. Your field is shorted to the case. At least I now know that there is actually something wrong. I didn't pull it off for nothing. The tech pokes at the generator.
Bearings are good.
Sometimes the brush holder wears and short out the field, but this looks good. It's in pretty good shape, really, 'cept for the field. But I don't know if I can get the part. He felt that was a bit steep. He looks it up in his parts book.