Field wire not energizing when ignition on.

[Grumpa]

Need possible causes. Looking at ignition switch next.
Got the alternator, stock style, externally regulated, for '74, checked at O'Rielly's today and it checks out. Put a jumper from the batt. wire to the "field" terminal on the back of the alternator and it started pumping over 18 volts. Has a new voltage regulator and the old one that was somewhat working, didn't work either.
I put a DUI dizzy on it and right after that, the system quit charging. I've two wires left unhooked from the dizzy install, a purple one and I believe a green one. Maybe one of those needs to hook up to the distributor?

 

[TSB8C]

Here's the original stock wiring for the alternator and external regulator.



And here's the wiring for the alternator and the interconnects with the distributor.

 

[Grumpa]

I "accidentally" figured it out.
I did the jumper from the batt. output wire on the back of the alternator to the field wire with everything else hooked up and it was still pumping over 18 volts. Then I unplugged the jumper wire and let it sit and idle with the headlights on for a while and put a voltmeter on the batt. and it was showing a little over 13 volts.
So I decided to drive it to town with my jumper wire and voltmeter in tow and see how she would do. Drove the 3 miles into town with the lights and heater blower on then stopped in a parking lot and checked the alt. output, 13.25 volts. Yay!
Now to see if I really fixed it or not. I remember someone telling me about jumping voltage to the field on old generator cars and I'm kinda wondering if that's what I did here. Oh, and the other thing I found was very loose connections at the field and regulator ground connections on the back of the alt. so I just cut off the plastic connector and put two blade connectors on each wire.