S122;

...typical charging sys failure symptoms...I don't believe they "went bad"!...as proven by a successfull Reciprocity test of the Gen...yes, there is something amiss in the charging system...that is all which can be definately stated at this point...but I still suspect that VR...referring to the diagram:

...the voltage measurement you made from D+ to DF is also suspect. I would expect Battery voltage at the D+ terminal (once the cut-in contacts close) and the VR to connect DF to chassis (allowing field current to flow and Gen output to come up), therefore I would expect 12+V across the two terminals...its better to make all measurements to chassis...otherwise it gets even more complicated...

I suggest you perform the Regulator Bypass Test in the Article while monitoring voltage across Bat. and report results.

Also, I can't overstress the importance of clean, tight connections throughout the entire charging system...this includes: Battery, Starter, VR-including mounting to chassis, Gen- including cabling to VR, IGN SW, Fuse Block-especially F1, chassis straps to bat and engine. I suggest you disconnect the bat from the car but to a charger, while you dissassemble and clean, one at a time, all the aforementioned connections, then reassemble with ACZP...then continue tests.

Good Hunting!