(800) 853-2651
SHOP NOW

JD420U voltage regulator

J

jd2cylman

Member
OK, I did a search on the webby thing, and all my manuals, except the JD40 SM2013 that's currently eluding me...
How do I polarize the regulator on this machine? Got it all back together and running (never unhooked the battery), and now it's not charging (coincidence, maybe... but). So I'd like to start by polarizing the regulator before I pull the genny. On the plus side, the gear pump primed right away and the 3pt worked perfect, with no leaks at the pump.
 

The regulator does not get polarized. The generator gets polarized, which can be done at the regulator. Your 420U likely has a Delco Remy generator. These are called an "A" system, the generator fields are grounded externally, in this case that ground is in the regulator. To polarize the generator hook all the regulator wires up (the battery must be properly connected). Before starting the engine use a jumper wire to momentarily jump between the regulator battery terminal and the Regulator armature terminal (sometimes marked generator). Do not jump between the battery and field terminals.
 
You first BEFORE starting Polarize the GENERATOR not the Voltage Regulator and insure BOTH the VR and Genny have a good ground.

If it fails to charge work through my Charging Troubleshooting Procedure linked below to help find the cause.

https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ttalk&th=2060825

John T
John Ts Troubleshooting
 
You must log in or register to reply here.

Similar threads

waugh621
Voltage regulator?
Replies
13
Views
396
wore out
wore out
D
Hot voltage regulator - No charge
Replies
4
Views
215
olddavid
olddavid
D
Hot voltage regulator - No charge
Replies
2
Views
173
Janicholson
Janicholson
4
Farmall A charging questions
Replies
14
Views
571
gene bender
G
M
M generator problems
Replies
6
Views
432
JonCT
J
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top