Voltage Regulator , Alternator, or….

[OR75]

I had the OECO 20082 on my 77J and I replaced it with the Zeftronics R1530B . Same metal plug as the OECO

only difference is the bolts footprint (you will only have 3 bolts (vs 4 for the OECO)  

[shawnd]

When I had Voltage Regulator issues, I had mine rebuilt by Consolidated Aircraft Supply in New York - https://www.consolac.com/ Might be worth giving them a quick call to see if they can service it for you and what options they might have. Mine came back like new.

[Planegary]

When I had my voltage regulator replaced my mechanic built a heat sink/ stand-off to bolt to the firewall with the original bolt pattern then the regulator bolted to the heat sink. If I ever need to replace the regulator again I will only have to remove the top cowl and as an added bonus my voltage regulator has air flow all of the way around it to try to help keep it cooler. And if the footprint of the bolt pattern changes it will only change on the heat sink

[201Steve]

Well, here’s the result. Checking resistance on pins when changing the VR, I got a funny reading on the meter that didn’t make sense. It resulted in disassembling the cannon plug itself, where I found the alternator field wire insulation chafed, where it was either very close to-or touching- its’ own grounded shielding. 
 

so it was either a grounded field wire, the regulator itself, or both. Either way, it’s all fixed and operating per spec. 

[RoundTwo]

Nice find and another great example of why throwing parts at a mystery problem isn’t the best way to go.