Headlights oscillating

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This just started.... or at least I just noticed it. With the headlights on dim and engine warmed up and idling, the brightness cycles from normal to slightly dim. Cycle time is around a second. When I rev the engine slightly, they return to normal steady brightness.
When running with or without lights, the ammeter is just right of center, slightly charging, in the normal position.
I don't suspect a connection -- within the last 2 months, I removed and cleaned all the battery connections, including regulator and other parts when I was fixing a grounding issue.
Battery cranks start just fine. No other indications of failing battery.
Thanks folks,
Snuffy
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On Tuesday, August 4, 2015 at 7:39:00 PM UTC-4, Snuffy Hub Cap McKinney wro te:

to slightly dim. Cycle time is around a second. When I rev the engine sl ightly, they return to normal steady brightness.

n I was fixing a grounding issue.

check battery voltage with vehicle running at idle. it must be 13.8 volts
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On Tue, 4 Aug 2015 16:38:18 -0700, "Snuffy \"Hub Cap\" McKinney"

How old is the car? That was not unusual on older cars.
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On 8/4/2015 7:00 PM, snipped-for-privacy@aol.com wrote:

Well, he did say he cleaned the connections on the REGULATOR... That's either a clue or indication of cluelessness;)
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Snuffy "Hub Cap" McKinney wrote:

Some times one diode goes bad(opens or short)
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wrote:

anyway) 12 pole 3 phase devive, and is geares about 2:1 from the crank, so at 500RPM idle would be turning about 1000RPM, making about 60Hz power (if my math is anywhere close to correct) so any cycling would be in the 1/60th second range -a very high frequency flicker, not a surge with a 1 second period.
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snipped-for-privacy@snyder.on.ca wrote:

There are many things one would not believe until one sees one in person.
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On Tue, 04 Aug 2015 18:38:18 -0500, Snuffy "Hub Cap" McKinney

It wouldn't be something silly like a loose belt by chance? I've heard of belts getting shiny and slick also. Does the heater fan do anything unusual?
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On Tue, 04 Aug 2015 19:11:55 -0500, "Dean Hoffman"

a month or so, and the unsteady lights at idle will go away when the alternator is replaced. How many miles are on this beasty, and how old?? Is it the old Aeroscare?
I had the same problem on my '89 - replaced the regulator - no joy. Replaced the alternator - problem fixed.. I managed to pick up a good recently replaced rebuild at the wreckers for $30 (about 20 years ago)
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Yep, the same one. About 140K miles. Is that something that can be checked out before installing a new one? They ain't cheap.
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check voltage at batery at idle, it should be 13.8 volts and solidly .......
probably a bad alternator
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On 8/4/2015 10:59 PM, Snuffy "Hub Cap" McKinney wrote:

In my part of the world, some Advance Auto Parts And Battery have alternator testers. Some even have a man who knows how to do the test.
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On Tue, 4 Aug 2015 19:59:27 -0700, "Snuffy \"Hub Cap\" McKinney"

still "surge". A good analog voltmeter connected to the output of the alternator will show if the voltage is fluctuating.
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OK, will check it tonight. Yesterday while idling during the day, I noticed the ammeter oscillating. If I kicked the gas and released it, the oscillation stopped. Will check the belt also.
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On Tue, 4 Aug 2015 16:38:18 -0700, "Snuffy \"Hub Cap\" McKinney"

Could be worn out/sticking brushes in the alternator.
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In alt.home.repair, on Tue, 4 Aug 2015 16:38:18 -0700, "Snuffy \"Hub

Do you have a tachometer? Does the RPM oscillate?

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In alt.home.repair, on Wed, 5 Aug 2015 00:08:59 -0700 (PDT), Uncle

I dont' think that had mass airflow sensors or ECCs when they had regulators, but otherwise, a good idea.

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Uncle Monster brought next idea :

It seems to have an Ampmeter and are you old enough to remember when cars had them? :-Z
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Uncle Monster posted for all of us...

normal to slightly dim. Cycle time is around a second. When I rev the eng ine slightly, they return to normal steady brightness.

ts when I was fixing a grounding issue.

d on and the idle speed increases. I'd pull the air cleaner so I could see the throttle body to see if the throttle is being moved by the idle speed c ontrol motor. The engine control computer could be affected by a dirty mass air flow sensor which could cause the idle speed fluctuation. (¬?¬)

Bingo, it could be his garden tractor.
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On Thursday, August 6, 2015 at 5:00:53 PM UTC-4, Tekkie® wrote:

In which case it might have neither a generator nor alternator, but instead a magneto.
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