Alternator test procedure
Don't discount the REST of it. I have found OPENS in the CHARGE WIRE/ ammeter circuit. In other words, the alternator / regulator were just fine, but the power could not get to the battery. Monitor voltage AT THE alternator stud. If it is way way high, but not charging, you have a problem in the charge wire
It's VERY helpful to actually know kinda how these work
FIRST, the VR MUST BE grounded. MUST
The 70/ later has a power wire from the "run" circuit to one of the two alternator field connections. (light blue.) This also branches off and feeds the VR. The green wire from the VR sort of controls the "amount of ground" at the alternator to control it's output. More field current, more output.
Don't discount being fooled. If you remove the green and ground that field terminal, how do you know the blue is supplying power to the field? CHECK it