There's a guy with a '69 with a thread going currently so I hope I don't mix the two situations up.
Fried. Well probably, but might as well cherck before throwing parts at it.
A couple easy checks
1. Key off and then in Run. Measure voltage at the regulator's input. A probe can usually be slipped in the back of the connector. The next closest location is the ballast resistor. Voltage at either of these should be the same as at the battery positive. Measure at the battery with the key still in run. Then turn key off.
If not showing full battery voltage at the regulator with key in run, then there is a connection problem before the regulator.
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2. Bypass the regulator. Because this regulator both measures the voltage to ground, and controls the flow from the positive, if its stuck open for any reason a temporary bypass will allow current to flow to the rotor.
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If you can, before doing the bypass test, put the battery on a slow charge. 2 amps if it has a choice of scales. While the alternator can recharge the battery, there's no real control on the current. So when a battery is deeply discharged, it will draw a lot of current even at 13.5 to 13.8 volts. Even more if the voltage is higher. With the bypass test, there will be no voltage regulation! Voltage will go up with rpm. Keep the rpms down. Watch the ammeter. Try to keep it under 20 amps. If looking at a voltmeter, try to keep the system voltage under 15 V. High currents are hard on all the components (alternator, wires, connectors and battery) and more so when things are oxidized or dirty.
After starting, the rotor should get power just like if the regulator was letting maximum current through.
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The one on the car now may have solid state internals. The big advantage is less electrical noise, which is pretty much irrelevant when there's practically no electronics on the car. :)
The one on the bottom looks more original.
Whether one is more durable or holds a closer set point than the other, I don't know.
A lot of new stuff is pretty bad either in design or manufacturing quality or both. :(
With a electromagnetic points regulator, remove the lid. If there is a problem its usually obvious.
