Farm Equipment - chaarging system

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chaarging system

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=44133
Printed Date: 09 Sep 2025 at 8:49am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: chaarging system

Posted By: pabob
Subject: chaarging system
Date Posted: 20 Jan 2012 at 3:00am

off color tractor, but helping a neighbor. JD 2030 wasn't starting and he replaced the battery. Still not right and he called me. The tractor wasn't charging and the idiot light was burned out. Motorola alternator needed diodes and new brushes, this done by local alt repair shop. We reinstalled alt, cleaned bat terms and topped off batt charge. Starts fine and charges. Batt at rest 12.5 volts and 14.5 when running. Rate of charge does vary with speed of engine. Here's the rub. The idiot light is out at an idle but there is just a faint glow when full throttle. not really lit but just like an ember and you probably wouldn't notice in the sun light but in the dark shed you can see it. This is a new one to me. The shop said it might be the reg. but run it and wait to see if it works out. (right, my tractors don't usually heal themselves) Any ideas? thanks

Replies:

Posted By: stray
Date Posted: 20 Jan 2012 at 6:04am

Most idiot lights have 12 volts applied to one side of the bulb and grounded thru the alternator. When the alternator is sitting still it grounds the bulb. When it is working it applies 12 volts to the wire that goes to the alternator and the bulb goes out becuase it has 12 volts to both sides. I would say that you have a bad connection on the key side of the light that is not carrying the higher amperage when the tractor is at high idle.

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1969 190XT series 3

Posted By: pabob
Date Posted: 20 Jan 2012 at 8:56am

thanks stray for the reply we'll give that a check and that sounds like it could be it

Posted By: Gerald J.
Date Posted: 20 Jan 2012 at 1:23pm

I've had car idiot lights that glowed a bit when charging. Maybe it would help to use a lamp that takes more current at 12 volts. There usually are several current (and light output) options for each lamp base and glass size.

Gerald J.