John T

jgc · Mar 29, 2011

Hi John,
A friend of mine has a Case model "430" tractor that just barely turns off the charging light some of the time.

He says that it has "Prestolite" branded genny and voltage regulator.
Generator: model is GJT-7403 SN
Regulator: says "Prestolite: on it (3 wires).

John - any special advice or different tests required from your standard procedure.

Can you add the link to the latest version of your genny testing procedure please.

Thanks and Regards,
JGC

John T"s Troubleshooting

John T · Mar 29, 2011

Okay if you dead ground the Gennys FLD post and make sure the Genny itself has a good ground yet she still charges weak the genny (versus any VR problem) is likely the problem and it could be worn down brushes or dirty sticking brush hold down springys or a carboned or oily commutator or field or armature problems. The belt needs to be good n tight and good genny and VR grounds.

Im guessing it a Voltage Regulagtor system and 2 brush genny versus a 3 brush genny and a cutout relay from what you said??

Para 5 of my standard procedure covers the VR by pass test noted above so run it and insure good genny and VR grounds and all other good wiring but if she still charges weak (with FLD grounded) the genny needs some attention (brushes,,,brush hold downs,, open fields,,commutator,,armature)

PS the Motor test described in my procedure may show field problems such as if she dont speed up when youre motor testing it and unground the field

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=665110

John T
John Ts Troubleshooting

M-MAN · Mar 29, 2011

John T;
Are you sure the Case uses an A class? Prestolite made both but I don't know how to tell them apart.

John T · Mar 30, 2011

Very good question M Man, Im unsure if they used an A or B systyem, but I was thinkin it was only Ford that used the B in those days???

As Im sure you know to full field the B system you have to apply full battery voltage to FLD instead of grounding it SO IF IT IS THE B SYSTEM ID HAVE TO RE WRITE MY PROCEDURE

Good question, heck if I know, I probably shouldnt have answered as I did not knowing, my BAD

John T

jgc · Mar 30, 2011

John T.
Used your procedure.
The system wasn't charging at all.
The genny motored as expected.
The genny put out tons of power into a load resistor.
The system charged when we manually closed the large relay.
It wouldn't close on its own, but it stayed closed on its own.

We jumped across the regulator from the batt to the arm terminals and zapped the resistor that connects to the field terminal.

The regulator looks pretty bad so we have ordered a new one.

Do you have a schematic for a regulator that has three internal relays. I'd like to understand the circuit.

Thanks,
JGC

Donny Joe · Sep 6, 2017

JGC, What voltage regulator are you using? I realize this is an older post, but I too am having charging issues. Believe it's a VR problem but can not locate one. Where did you buy and do you have a number. Mine is 3 terminal flat base mount. Any help would be appreciated.
Thanks

John T - Another charging problem - your advice requested

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