'69 Voltage regulator

[Jeffrey S.]

What are the usual symptoms of a voltage regulator that is starting to go bad? Here's what is happening. Just the last 2 times I ran my '69 at night, headlights on, all at once the battery indicator started o swing wildly and then went to full discharge, bounced around, and then returned to normal for the rest of the trip. This has happened twice. Before I strt throwing parts at it, I was hoping for some advice.
Jeff

[Owen L.]

Re: '69 Voltage regulator

Have you checked running/charging voltage at the battery?

If you have the GM regulator with points, maybe try dressing them with a file just like you would ignition points and then clean any oxidation from the terminals.

[Jeffrey S.]

Re: '69 Voltage regulator

Owen,
Thanks for the reply. I will check the voltage when the battery guage is normal and report back. The voltage regulator in '69 was solid state, internal to the alternator and is not serviceable. Just replaceable.
Jeff

[David M.]

Re: '69 Voltage regulator

Basics first,
Step one:
All connections need to be verified as good:
-clean battery posts and cables
-positive cable to the starter. Pull it and clean the connection Same for the solenoid wires.
-negative cable from battery to the frame. Pull it and clean the connection.
-negative cable on the passenger side of engine block to frame.(by engine mount)
-alternator connections
-the VR itself needs a good ground. Check the 4 connectors in the VR connector.
CAREFULLY remove the VR, pull the cover inspect.
Look at the backside and under the cap for loose wires or burn marks.
Clean dirty points with a lint free cloth/wipe with brake or contact cleaner. Or leave it alone. A file removes the protective tungsten layer and reduces point contact life. Moot point if they are burnt.(Replace it)

Erratic amp gauge is usually one of three things.
-Bad connection within the charging system
-Bad VR
-Bad alternator (rotor/stator windings or diode bridge)

BUT before you start throwing parts at it do the above basic trouble shooting.
After you verify all items in step one are good take a running voltage reading.
Should be a steady 13.8 to 14.2 VDC. No less than 13.8, no more than 14.5.

Load test the battery. Does it pass?

Keep in mind 55-year-old cables may need replacing.
55-year-old electrical connections need to be refreshed.

After you verify all of this and it’s still acting up, I can walk you through the alternator/VR trouble shooting steps which you can do in your garage.

[Jeffrey S.]

Re: '69 Voltage regulator

David,
Thanks very much for taking the time to outline what needs to be done. This will take some time but I will be trying to isolate the problem sometime this week. The steps outlined to check the VR are not applicable to this since that is internal to the alternator and not serviceable. However, all of the grounding checks etc. are and will be checked. I will get back when those are done.
Jeff

[Joe L.]

Re: '69 Voltage regulator

Owen,
Thanks for the reply. I will check the voltage when the battery guage is normal and report back. The voltage regulator in '69 was solid state, internal to the alternator and is not serviceable. Just replaceable.
Jeff

Jeff------

There are procedures in the Chevrolet Overhaul Manual to check all of the internal components of the alternator. The procedures are relatively simple and can be accomplished with a VOM meter. It does require disassembly of the alternator but this is also quite simple.

[Jeffrey S.]

Re: '69 Voltage regulator

Joe,
I have taken this alternator apart and you are right, it is not difficult. Before I go there I will check everything else first.
Jeff