Alternator Field CB

[rgpilot]

When I shut down my 93 201 the alternator field cb usually pops. If I delay the turning off the Alternator Field Master for about a minute it usually doesn't pop. CB has been changed, but it didn't help.

[rgpilot]

My alternator field CB usually pops when I shut down the alternator field master. If I delay turning off the master switches for about a minute, the CB usually doesn't pop. The CB was changed by the previous owner who had the same problem.

[Piloto]

Try replacing the field diode. This could be located in the voltage regulator or next to the alternator. The purpose of the diode is to discharge the high voltage created by the field when disconnected. It also prevents switch contacts welding.

José 

[Wistarmo]

Piloto is correct.  Replacing the diode on the alternator works.  However in my case ('93 M20J MSE), the problem recurred within a few months after replacing the diode.  Does anyone have any thoughts about a more durable diode solution?

[Piloto]

Quote: Wistarmo

Piloto is correct.  Replacing the diode on the alternator works.  However in my case ('93 M20J MSE), the problem recurred within a few months after replacing the diode.  Does anyone have any thoughts about a more durable diode solution?

[rgpilot]

Fixed the problem with the alternator field CB popping on shutdown. Added a Zener Diode from the hot side of alternator field to ground. Colored band on the diode must face the positive side of the alternator field.

[Jhj123]

Wow, I sure am glad to have found this thread. I am having the same problem?m, the Alt Field CB pops when I turn off the switch at shutdown. If there is a delay it doesn’t. I’ll give the A&P the info above, hopefully it fixes it.