Old problem, New question

Sun Jan 02, 2005 12:40 pm

I have a 58 Cub with a six volt system that refuses to charge even though extensive checks and tests say there is nothing wrong. I've heard that there is an A & B style of 6 volt regulator and using the wrong gen/reg combo could cause my problem. Can anyone shed any light on this subject?

Thank You

Sun Jan 02, 2005 4:29 pm

Farmall A and B tractors never had regulators on them only cutout relays.

I would feel you have a poor ground if everything else checks out.


Sun Jan 02, 2005 4:35 pm

Wire, I hate to disagree, but later ones did have regulators,. According to my parts manual they started with serial 224401 for standard cub and 18701 for loboy

Sun Jan 02, 2005 5:35 pm

John. I don't think Wireharness is talking about "Cubs". He mentioned Farmall "A" 's & "B" 's.

Davek. Never heard of an "A" or "B" type wiring for a Cub. Only the early "cutout" type and later "regulator" type. However, just because I never heard of it doesen't mean it wasn't so............

I would agree though, you have a ground or short problem.

Sun Jan 02, 2005 5:44 pm

You are correct, I misread his posting. I do remember one earlier about a Napa regulator womeon was looking at as a replacement, but there were two different ones depending on the wirirng.

Sun Jan 02, 2005 6:16 pm

This thread reminds me of "Ballad of a Thin Man"

There are 2 different ways to design voltage regulator circuits. They are (at least in terms Delco has used) refered to as "A" circuits and "B" circuits. "A" circuits have the hot end of the field coil connected directly to the generator output and the VR contacts of the regulator control grounding of the field coil. "B" circuit generators ground the field coil internally and the VF contacts of the regulator control application of output voltage to the field. Maybe davek's original question is about that. Regulators from one type system can not be mixed with generators from the other. However, I don't think I have ever run into a "B" type system and doubt that you got mixed into any components from one either.

As far as Farmall A and B tractors are concerned, most that had electrical systems used the Delco components. All of these used the same 3 brush generator and cut-out system (same parts) as the early Cubs until mid-1950.

The Cubs went through a number of component changes over the years.

In the case of davek's problem, if the individual parts seem to check out, it is time to go back to the basics. Make sure all the wiring is by the book. Then recheck all the grounds. It almost has to be one or the other.

Sun Jan 02, 2005 7:15 pm

davek - your profile states you live in central Ohio. I am 25 miles south of Columbus and would be willing to help you check it out if you would like if you are reasonably close. As Jim said, your components are likely the correct ones. Just go back to the basics and eliminate causes one by one.

Tue Jan 04, 2005 8:22 am

Thanks for all the input. It does sound like I have all the right components. I'll just have to get the fine tooth comb out and go through the wiring again.

Tue Jan 04, 2005 11:26 am


The guys have you on the right path. I am willing to bet dollars to doughnuts that you have a bad ground - and I bet it probably is close to the battery.

Other thought, 6v systems were usually positive ground. Check that out as well. AND do not forget to polarize the generator.

According to the Cub Bible (Owner's Manual)

"After making certain that the grounded battery terminal is the positive (+) one, momentarily connect a jumper lead between the "Bat" terminal of the regulator (read also cut-out) and the "A" terminal of the generator. This allows a momentary surge of current to flow through the gerator which correctly polarizes it. Reversed polarity may result in vibration, arcing and burning of the relay contact points.

Important! Do not touch the jumper lead to the "F" terminal on the generator, as this will damage the regulator."

What I have done to assist this is to hook a pair of ring terminals (Spae Nauer clips) with about 8 inches or so of 10 guage wire and terminated with a tube connector. I then lay these two wires up inside Ellie's hood. When I need to polarize the generator, all I have to do is to short these two terminal ends with a short piece of wire and presto bang, I am done. This alleviates the need to remove the hood to polarize which is a great big PITA.

Hope this helps!