Wiring for Case SC

Wrangler1973 · May 2, 2020

I know I screwed up by not taking pictures when I first started working on my SC. But could anyone explain or have a diagram for wiring from starter to starter button, the dash panel. If those who own an SC if you have a toggle switch running to the alternator or magneto, is this necessary, what is its purpose? It is a 12 volt conversion if that helps.

This is the final obstacle I need to overcome (hopefully) to get my tractor running again.

Thanks in advance for any advice.

rvirgil_KS · May 3, 2020

Here is a diagram I have for an SC

If you have a double pole toggle switch, one side could be used to excite the #1 pin on Delco alternator to start charging, other side could be used to ground the magneto to stop the engine

Wrangler1973 · May 3, 2020

Thanks for the diagram and info. So if I follow this diagram the wire from the ammeter to the generator (on the diagram) would be the wire running to the alternator's first or left pin? Or would that wire go from the toggle switch to the alternator with another wire going to the magneto? Is it a necessity to have that toggle switch to alternator and magneto?

rvirgil_KS · May 3, 2020

"So if I follow this diagram the wire from the ammeter to the generator (on the diagram) would be the wire running to the alternator's first or left pin?"

No. This wire connects to output of generator, so it would connect to output of alternator.

On the common Delco 3 wire alternator, The right or #2 pin can connect down to the output. The #1 pin needs a momentary voltage to start the alternator to charging. This can be done with a toggle switch but if it gets left on with engine off it will cause battery to run down and may damage the alternator.

You need a switch to turn off the magneto and another to turn on the alternator

Toggle switch can work for magneto as it grounds that post to turn engine off.

Magneto is completely separate by itself and must not have any battery voltage applied to it.

For the #1 alternator pin with a magneto ignition, I would use either a momentary push button switch or an oil pressure activated switch.

Ken Christopherson · May 9, 2020

I recently did a 12 volt conversion on my Case SC with Magneto ignition... But instead of using a toggle switch or 'excite light', I installed an oil pressure switch to act as the excite circuit. Easy to do and can be had at NAPA for reasonable price. Video link below.
Kens SC 12 volt Conversion

forrest allen · May 31, 2020

This diagram shows a negative ground. I thought that these were positive ground.

forrest allen · May 31, 2020

And I just saw that it is a 12v conversion. Should have read closer.

Wiring for Case SC

Wrangler1973

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rvirgil_KS

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Wrangler1973

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rvirgil_KS

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Ken Christopherson

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forrest allen

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forrest allen

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