Electronic Transistorized Alternator voltage Regulator test

[Syleng1]

Good afternoon All,

Yesterday I was driving the Demon and the headlights and dash lights went into "blinking" mode and then went dim. Knowing I was one of two things, I went on line to find info on the wiring harness schematic so I could chase down my issue. Now my 1972 Demon has the electronic voltage regulator and 2 field wires out the back. This information is for that style regulator and not the 71 and older style. I was really perplexed that with all the information on the web, there was nothing to actually "check" the regulator and alternator. So because I am very low on time I went to buy an alternator (rebuilt) and a new voltage regulator.

In the regulator box (I chose to go regulator replace first as it was less expensive that the alternator) I found a trouble shooting chart that for the first time shows how to test the alternator and wiring BEFORE you replace anything.
I wanted to share this with you. I can send any one who asks (with your email address) a .pdf file for you to print out at home.

Turns out all I needed was the regulator. Alternator is charging great at 13.8volts and 55 amps.

Thanks for your time.
Joe

 

[67Dart273]

I guess if you think there is no information, you have not read many of my posts.

While that pdf is a quick test, for many guys on here that don't really understand this, there is a LOT left out

Example. What if the jumper test does NOT cause a charge? You go out buy an alternator, and guess what? It STILL doesn't charge!! WHY!!?

Several reasons.........

Maybe there's a break in the alternator field 12V supply, and the field is not getting 12V

Maybe there's a problem in the green wire, or a break right in the regulator connector

Maybe there's a problem in the output circuit of the alternator, and it essentially is no longer hooked to the battery

This is just a few. There are others.

One BIG BIG thing that causes guys grief with these systems, both charging and ignition, is that BOTH the ignition ECU AND the regulator MUST BE grounded. Because of the "crappy" mounting system originally used (firewall "threads") this can be no joke.

 

[KitCarlson]

A way to bench test them is use a variable voltage bench supply and a test bulb. The power supply + goes to I terminal, - to case. Test bulb to F and supply +. Start at 10V, bulb should light, increase supply voltage to 14V, test light will go off, above regulation voltage, and back on below.