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Re: 79 MGB Roadster Alternator Problems

To: mgs@Autox.Team.Net
Subject: Re: 79 MGB Roadster Alternator Problems
From: john.kahoon@juno.com (John c Kahoon)
Date: Tue, 1 Sep 1998 06:12:30 -0400
Does yor car have a "remote" voltage regulator ? If so, I'd be checking
that out
 ( you may have gotten rid of a good alt.)  I've just been leaning about
how this stuff works so..bear with me.
Your voltage reg. sends 12v to the Gen/Alt to turn ON the field windings
when it sees the 
voltage drop below a certain point. When ON it should put out about
14/14.5 v, off
about 1.5v (thats also why a DEAD battery will not get recharged, not
enough volts to operate
the field windings ) So you want to check ? take a volt meter and hook it
to the battery,
then disconnect the "skinny" wire from the Alt/Gen. Now hook up a direct
wire from the Battery
to the Skinny wire post ( you are in effect "hotwireing the Alt/Gen). If
your Battery has 12v, it WILL operate
the windings and start charging. Look for the volts at the Battery to
slowley start to increase.
    I have a Gen. so I wouldn't know how to tell if an Alt has the
"internal" voltage regulator.
Just guessing, but I would think the "internal" has only one wire going
to it.
This test will NOT work if you have an Alt. with an internal regulator.
If anyone can elaborate futher, I'd like to know more.

john.kahoon@juno.com
71 midget

On Mon, 31 Aug 1998 21:13:01 EDT DBAVERY1@aol.com writes:
>Hi All,
>
>Well the good news is we completed another long trip this weekend and 
>had
>excellent top down weather.  Went from Lansing, MI area to Madison, WI 
>and
>back.  I did have a problem however and wondered if anyone can offer 
>help.
>
>We left Friday night the entire trip requirred headlights and the only 
>other
>thing going was the radio.  After 5 hours of the trip the ignition 
>light came
>on real faint.  I  turned off the radio and that was enough for the 
>light to
>go off.  It flickered a couple more times on the remaining 2 hours of 
>driving.
>When I stopped and turned off the ignition key the ignition light came 
>on
>bright - key off and out of the ignition.  I unhooked the battery 
>cable so the
>battery wouldn't drain.
>
>The next day I hooked up the cable and the ignition light was on all 
>the time.
>Well it was alternator time.  Hard to find anyone with one on short 
>notice but
>I got a rebuilt from a Madison parts house and the car was back to 
>charging
>perfectly.
>
>Well now goes the trip home - this time full daylight so NO headlights 
>on and
>we didn't listen to the radio the entire trip so no accessories used.  
>Again
>about 5 + hours out and we stopped for a bite to eat.  When I started 
>the car
>the ignition light was lit dimly.  If I got the car up to 3500 RPM the 
>light
>would go off so it appeared it was NOT charging at speeds up to 3500 
>RPM.
>Well I finished the trip at 3500 RPM and am safely home.
>
>When I got home I felt the alternator and it was very warm but I've 
>never
>tried touching it after a trip so I don't know if it is hotter than 
>normal or
>not.  I felt all the wires from the alternator and they were fine - 
>felt cool
>so I figured it wasn't a big draw causing the problem.
>
>Does anyone have any suggestions what might be going on?  Did I just 
>get a bad
>alternator on the rebuild?  The starter just went out prior to the 
>trip so
>that was new at the start also.  Any help or suggestions will be 
>appreciated.
>
>Denny
>


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