Mike - forgive me but trying to understand. When you say A+ are you referring to the Alt field terminal? Assuming so, if I attach a battery charger to the Alt Field post do I ground to Alt Grnd or engine grnd or does it matter which? Also, how would the battery charger show any current without the alternator connected to ship power?
Woa there. Your Regulator is special. It has a crowbar circuit. You did not successfully test the crowbar circuit.
Here is a way to do that test. In your airplane, take the big A+ wire off the alternator and apply 14 volts to the A+ wire post on the alternator with a powersupply (battery charger should work). With the Alternator switch "Off" are you drawing any current from the powersupply? The answer should be no. If yes, then your alternator is bad, likely shorted diode.
Next apply 14 volts to the A+ wire that is no longer on the alternator with a powersupply (battery charger should work). Turn "On" the alternator switch. The current out of the powersupply should be 0. If it reads 1 or 2 amps or the 5 Amp breaker blows then your Regulator crowbar circuit is bad.
Can you take
that regulator apart? It is probably fixable for a lot less $ than a new one.
My money is on the regulator being bad...
Mike N3QP Q200