The alternator is working.
I have tested it just using I - ignition , A - battery,
F- field, and minus on housing of powermax regulator.
And I used an another switch (no switch on instrument panel) to bring battery voltage on ignition. While the engine was idling I switched regulator on and I could notice the change of engine RPM
With low RPM
voltage on field was 13V and with higher RPM it droped to 5 V . I have a digital instrument so is harder to say the value because numbers are all the time changing. I beliewe I could take this as normal behavior. And conclude that alternator is ok.