Problem seems to be resolved. I took the alternator to a rebuild shop in Kent, Wa. called "the Rebuilder" to have the Schucks lifetime alt checked. They found that the stator was shorted and the diodes were not replaced. I bought their rebuilt alt and installed it. It has been charging properly for 3 months with no other changes. I trust that this one will last. No more Schucks for alternators. Thanks for all the advice folks.