JD 630 resister??

[old bones]

What is the resister on the backside of the dash for? I bought a new coil that's internally resisted, so do I need to use the resister?
Switching to 12v + ground and alternator, and rewiring it. Pretty sure the switch is shot, too.

Thanks.

 

[wore out]

What is the resister on the backside of the dash for? I bought a new coil that's internally resisted, so do I need to use the resister?
Switching to 12v + ground and alternator, and rewiring it. Pretty sure the switch is shot, too.

Thanks.

First of all, your new coil isn't "internally resisted", it is simply wound with more turns of wire and/or ''lighter'' wire to allow it to be used on 12 Volts WITHOUT the need for an external primary resistor.

The original system used a coil with about half the primary resistance AND an external resistor in series.

During operation of the starter (which greatly reduces voltage available to the ignition system) the resistor is bypassed/taken out of the circuit giving more voltage to the coil for a HOTTER spark while cranking.

So, while good-intentioned, ASSUMING the original bypass system was intact and functioning, removing the original coil and resistor and replacing them with a ''true 12 Volt coil'' is actually a step backwards.

But most likely, it will work ''O.K." and you'll ''get by'' with the ''upgrade''.

 

[used red MN]

What is the resister on the backside of the dash for? I bought a new coil that's internally resisted, so do I need to use the resister?
Switching to 12v + ground and alternator, and rewiring it. Pretty sure the switch is shot, too.

Thanks.

I do not have a lot of time this morning for a lengthy reply. I just want to make sure you misstated your intention or at least inform you it is incorrect. If you are switching to a commonly available automotive alternator you will want to (or actually you have to) have the tractor “negative”(-) ground on the chassis. Connecting the coil with the correct polarity negative small primary terminal to the distributor and changing the direction of the current flow through the ammeter is all that is needed to accomplish this. Connecting a common automotive alternator to a positive ground system will cause a direct short.

 

[old bones]

Yes, I misstated. Meant to say 12v neg ground. Going with a new one wire Delco alternator. (I did that with a '48 B, and it worked great.) This tractor was literal basket case when I got it. The previous owner had an alternator on it- sort of.
The primary wire that ran from the alternator to the voltmeter and the wire that ran from the voltmeter to the starter were fried. Other wires were under the screws/nuts with no terminal ends on them, and most were "as hard as Chinese arithmetic", with the insulation cracking, including the battery cable under the platform, from the battery to the starter.

I'm pretty sure that not all the wires were in the right places, so I'm rewiring it completely.
Pretty sure the switch is fried inside. Using an ohm meter, with one lead on the switch's BAT terminal, nothing coming out of the IGN terminal when it's turned to the first position, until switch is in the next position. Then the headlight, back light, and ignition terminals are hot.
There was a wire coming from an unlabeled terminal on the switch to the signal wire for the alternator, also. This terminal shows nothing now, in any position.
Still trying to figure out the "switch/starter button/coil/resistor" wiring, and looking to find a wiring diagram for it. My 1954 60 is a somewhat different switch setup, since it doesn't have the starter button.

When it showed up here, there were 3 wires on the starter button. One to the resistor bottom/output, one to the IGN terminal, and one to the starter solenoid. Two were always "hot", together, and one was only hot when the button was pushed.
I'm thinking that this last one should be the power input from the switch, and the other two would then be hot when the button is pushed, one to the starter solenoid, and the other to the output/bottom side of the resistor (giving the coil full "hotter" voltage during startup).

I've been wrong before, that's why I want to find a proper wiring diagram for it. The IT repair manuals I have for the 630 and 60 don't show any wiring.

Thank you. I do appreciate the help. Years ago, when I was working on my A and 60, the knowledge and help here was immense.

 

[old bones]

First of all, your new coil isn't "internally resisted", it is simply wound with more turns of wire and/or ''lighter'' wire to allow it to be used on 12 Volts WITHOUT the need for an external primary resistor.

The original system used a coil with about half the primary resistance AND an external resistor in series.

During operation of the starter (which greatly reduces voltage available to the ignition system) the resistor is bypassed/taken out of the circuit giving more voltage to the coil for a HOTTER spark while cranking.

So, while good-intentioned, ASSUMING the original bypass system was intact and functioning, removing the original coil and resistor and replacing them with a ''true 12 Volt coil'' is actually a step backwards.

But most likely, it will work ''O.K." and you'll ''get by'' with the ''upgrade''.

Just going by the lettering printed on the outside of the new coil.
Needless to say, I'm not an electrical guru