Solid State Regulator Testing

OKCM38CDN · Post by **OKCM38CDN** » Tue Aug 23, 2005 6:18 pm

Is there a method of testing / repairing a solid state regulator other than a swapout...

I think mine is bad and do not have one (good or otherwise) to swap with to test.

Any help greatly appreciated... Once I get the charging system fixed; I just have a few gauges to work and she will be 100% ready to drive...

Thanks

OKCM38CDN · Post by **OKCM38CDN** » Sun Aug 28, 2005 7:51 am

I was able to open my Solid state regulator and found that the 4 output pins on the regulator are all connected together...

There are no shunts installed for an ammeter, all are hot with 24 volts all of the time...

The model I have is a Singer PN 26640473-03 FSN 2920-800-7218; if someone else has one of these I would be greatly interested to know if this is normal for this part. Just remove the 8 screws holding the cover on and look at the four pins on the wiring harness side of the regulator...

Thanks...

Post by **wesk** » Mon Aug 29, 2005 1:56 am

Yes this is normal for the transistorized regulator. The M38 with the mechanical Auto-lite regulator used all four pins of the chassis/battery connector on the regulator. A went to the battery, C went to the circuit breaker trio or the master switch and B&D were for the ammeter.
On the old Auto-lite regulator A&D and B&C were connected internally with a shunt between A&B. Since the Tansistorized regulator doesn't have a shunt because they are normally used with a voltmeter the factory just bussed all four together so you'd have a voltage signal available on B or D for your voltmeter. Bottom line is ammeter doesn't function when you install a transistorized regulator in place of the Auto-lite mechanical regulator so you must switch to a voltmeter from a later M series and use only one of the two leads (wire #'s 8 & 9) from pins B & D.

As you can see here in the Auto-lite regulator the shunt bridges the power running between the battery and the generator and the power flowing from the regulator to the jeeps user circuits.

As you can see here there is no shunt used in the transistorized regulator between the A&D and B&C pairs of pins.

This is an enlarged direct comparison between the two regulators and their pin arrangements.

OKCM38CDN · Post by **OKCM38CDN** » Wed Aug 31, 2005 5:20 pm

For those that have it check out Military Vehicles Magazine, Febuary 2004; there is a great article on the solid state regulator there...

It pays to save old magazines...

repelado · Post by **repelado** » Fri Nov 16, 2007 2:11 pm

Wesk,
I've surfing the forum for quite a while, and finally I've found what I've been looking for so long.
You posted the schematics I've been looking for so much time!!!
Is there any chance tha you might post the same schematics, but with a better resolution.
Otherwise, please tell me if there's any chance you could send them to me by email.
Thanks very much in advance.

Carlos

Post by **wesk** » Fri Nov 16, 2007 2:47 pm

Hello Carlos,
The diagram is in the mail!