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Posted

Trusty multimeter in hand, I'm left to determine that I have a bad diode in my alternator.

I've been perusing the forums and https://studebaker-info.org/Tech/Bhend/avantalternatorarticle1.pdf by Bill Henderson. 

(Awaiting the shop manual to arrive.)

I have a call into a local auto electrical rebuild shop and I'm poking around the alternator. I'd love to have a backup, like one of the Honda or Toyota alternators like others have done so I can still drive my daily while the original is being rebuilt. 

I'm not a good electrical diagram reader. I have three wires coming from the harness to the alternator, white (or so faded they look yellow to me), white with black stripe and white with red stripe. The resister looking thing attached to the back of the alternator -- is this the Prestolite regulator? (see img 1). Whatever it is, it is not actually attached to the alternator, as I found it loose, not broken, in the boot. (Img 2). The red stripped wire goes to the terminal with the boot, the black-stripped goes to the other terminal, and the solid looks like it is being grounded to the post that holds the "regulator".

Thoughts/Comments/Suggestions welcomed.

-Dobb

image.png.649a7ec30e930497a385d8648d9eb9a5.png  image.png.16ebdea41d71a30f9807b05b5f85a0d0.png

 

Posted

The round "can" is a radio noise suppresser condenser, or more commonly called a capacitor. Not any sort of voltage regulator. The other wiring seems correct. The white with red stripe is to the main terminal, the one with the black stripe goes to the smaller terminal, often a spade push on connector if original. Then the plain white wire is ground to the case. The voltage regulator is in front of the master cylinder on the drivers side inner fender.

Posted

Thank you. So it's okay that the capacitor is not actually hooked up to anything? How would I know if I need to attach it?

Posted

(still awaiting my shop manual)

Would one of these be the external regulator? 

image.thumb.png.081a31c70f5a6d4723fcce6e2f010f36.png

Posted
16 minutes ago, DobbM said:

(still awaiting my shop manual)

Would one of these be the external regulator? 

image.thumb.png.081a31c70f5a6d4723fcce6e2f010f36.png

Yes … black ‘box’ marked 2

Posted

Ok, I installed the new alternator and the car is running much better. However, the battery is not being charged by the alternator. Also, the ignition powered wire isn't delivering 12v. My only assumption is that the external regulator is actually bad. I rewired according to the above referenced article by Bill Henderson. 

Next step is to wire the BAT alternator terminal directly to the the battery, with inline 60amp fuse, and just bypass the regulator entirely. 

My next question is how to get 12v to the alternator when the ignition key is "on"? 

(My shop manual is in the mail and should be here Monday.)

Thank you everyone.

Posted
59 minutes ago, DobbM said:

Ok, I installed the new alternator and the car is running much better. However, the battery is not being charged by the alternator. Also, the ignition powered wire isn't delivering 12v. My only assumption is that the external regulator is actually bad. I rewired according to the above referenced article by Bill Henderson. 

Next step is to wire the BAT alternator terminal directly to the the battery, with inline 60amp fuse, and just bypass the regulator entirely. 

My next question is how to get 12v to the alternator when the ignition key is "on"? 

(My shop manual is in the mail and should be here Monday.)

Thank you everyone.

Do you have a voltmeter?… That would identify how much current and where it is going… or not going…. Even a basic 12V test lamp will allow you to ‘see’ the electricity.

Posted

Engine running, and the battery is registering about 12.6v (same as with car off, key-off). Also used the multimeter to test the 12v key-on power and nothing. 

Where's a good place to get the key-on power? 

There are 4 terminals on the external regulator, three go to the original alternator, one of which is supposed to be key-on power. Is it feed power from the battery side of the starter? Just looking for a clean way to grab that key-on power. 

Thanks.

Posted

(Manual arriving Monday)

I believe this is the starter solenoid. There are 2 posts that have a smaller gauge wire attached to them (Image 2). One of them is should be key-on hot, correct? They both disappear into the harness.

Still looking for a source to have key-on 12v power for the alternator. Per the above referenced article: "The “IG” terminal needs a wire connected to it that is hot with the key turned to the ON position. Moving the white with black stripe wire from the FLD connector to the IGN lug on the voltage regulator will provide that." Since this is not providing any voltage to the alternator is why I believe that the external regulator is bad.

 

Thank you.

image.thumb.png.1a2f1878de5eb9ec39e109dd480b0df1.png

image.thumb.png.357ef31a0bb64fc7f70fbb587decf1b4.png

Posted

Dobb

This is easier to read than the shop manual version.  Power from the alt. Goes to the regulator and then thru the amp meter before going to the battery, so check those connections and for continuity thru the amp meter also.  
Steve. 
 

IMG_2947.jpeg

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