Question about 1968 Dodge alternator rectifier

[1968_Satellite]

What are the symptoms of a failed/failing rectifier in a 1968 round back alternator? I was talking to a friend who has a few late 60's mopars and he told me he had one fail and it pegged the meter,made the lights flicker and ruined the battery. Not talking about the regulator,talking about the rectifier inside the alternator that turns the ac into DC. Anybody had this happen before? If the rectifier failed wouldnt it just stop supplying voltage or would it send ac into the system?

 

[Jerry Hall]

No facts to back my guess up, but I think it just quits charging. I've never had one fail as described.

 

[Don Frelier]

It's possible if a diode were to fail "shorted" rather than open.
Not very common from what I've seen.

 

[twecomm]

A replacement alternator is not all that expensive. If you have doubts, probably best to just install a similar type new or remanufactured unit that would prove if there is an issue with your existing unit. I would expect that an open diode would not provide a proper output. A shorted diode however would create a path to discharge and eventually yield a dead battery and could damage wiring. Also, if a diode is shorted, you would likely hear a "winning" noise varying with engine RPM's from the AC component coming thru the speaker of the cars radio. Again, I'd just replace it if suspect.. Just my opinion.