JD60 Ballast Resistor

[gunther9]

Does anyone know where the ignition ballast resistor was located shipped from the factory? There's a ballast resistor on the ignition/light switch but after checking switch operation with an ohmeter I'm sure that resistor drops voltage to the front headlights when the switch is in the D(im) position.
 

[Rich Duane]

The Ballast Resistor is mounted below the dash panel on the front side of the shift quadrent.
 

[gunther9]

OK, thanks for taking the time to respond Rich.
 

[Tom 43]

The JD A and the first number series which includes the 60 DON"T have a ballast resistor as delivered from the factory. Both the A and 60 us a true 12 volt coil. There may have been later service bulletins converting the 60 to a bypass ignition system as on the 520 and 620 etc. Conversion would entail a resistor, a 6 volt coil, a diffrent starter switch, and a bypass wire from the starter switch to the negative side of the coil.

If a ballast is used on a 60, you must also have a 6 volt coil otherwise you will have weak spark.
 

[gunther9]

It had a 6V coil with a ballast resistor mounted to the coil. Ugly. I don't know how it came from the factory. It's a later model 60 #6061643 so I assumed it was built with a 6V/ballast setup but I'm not sure.
 

[4010 puller]

So If you have a 60 with a 12 volt battery, you want to run wire from switch through a resister and into a 6 volt coil? What if you buy a coil with a resister built in? You would want a 6 volt coil with internal resister and that would work fine as well?
 

[Bob Harvey]

Nope, I have #6015864 - NO ballast resistor - 12v. When I got it in 1971 it was Neg. grnd, -still is.
 

[John T]

Gunther, I dont think your tractor had a ballast resistor (sure it could have, never say never, I saw all sorts of modifications in my many years as a used tractor dealer) Its a 12 volt tractor that used a 12 volt coil therefore NO BALLAST REQUIRED. If you used a 12 volt coil PLUS a ballast, the spark would be weak.


On 12 volt tractors (like the later 620 and 720 etc) that used a ballast resistor THATS BECAUSE THEY USED A 6 VOLT COIL and the ballast dropped 6 volts leaving 6 for the 6 volt coil WELL DUHHHHHHHH

NOTE: A 12 volt coil is typically labeled "12 volts" orrrrrrr "12 volts NOT for use with ballast" orrrrrrrrrr "12 volts NO ballast required"

NORE: Theres a misconception out there that some 12 volt old tractor coils have a stand alone ResisTOR inside the can WRONGGGGGGGGGGGGG

Contrary to what many lay persons believe who call them coils that have an "internal ballast resistor" YOU WILL NOTTTTTTTTTTTT FIND A DISCRETE STAND ALONE RESIS"TOR" TUCKED AWAY SOMEWHERE INSIDE THE CAN. The way a "12 volt" coil achieves its necessary 3 or so ohms of LV primary resistANCE is by enough wire coil length (more wire or more coil turns) orrrrrrrrr using wire with certain resistANCE per unit length so the ResistANCE end to end (+ to -) ends up in the range of 2.5 to 4 or so ohms so the points dont burn up and the coil doesnt overheat and handles the current when 12 volts is applied.


SORRY CHARLIE, DONT DISECT ONE AND EXPECT TO FIND A STAND ALONE "RESISTOR" HIDDEN INSIDE

NOTE they actually did make some very early automotive coils that DID HAVE a stand alone discrete ResisTOR in a seperate part of the can!! Many had like a ring where the internal can portions were seperated, coil in one end resisTOR in other end all by itslef!! HOWEVER in alllllll my years as a used tractor dealer (older tractors) I never saw a coil with such an internal resisTOR inside the can!!!!!!!!

Hope this helps, post back any questions

Best wishes and God Bless

John T
 

[Bob Harvey]

Oops, #6015867 - like it makes a huge diff. <;*)
 

[Bob Harvey]

Well said - Sir John.
 

[John T]

4010:

YOUR QUESTION: So If you have a 60 with a 12 volt battery, you want to run wire from switch through a resister and into a 6 volt coil?

ANSWER: You could if you like!!!!!!! or else simpler to just use a 12 volt coil that way you dont have the wiring worry and extra connections and expense of a then un needed ballast!!!

YOUR QUESTION: If you buy a coil with a resister built in? You would want a 6 volt coil with internal resister and that would work fine as well?

ANSWER: SEE MY POST ABOVE, YOURE NOT GONNA FIND A COIL THAT HAS A STAND ALONE DISCRETE RESISTOR TUCKED AWAY SOMEWHERE INSIDE THE CAN

HOWEVER, You CAN FIND a "12 volt" coil orrrrrrrrr a coil labeled "12 volts NOT for use with ballast" orrrrr a coil labeled "12 volts NO ballast required" AND GUESS WHAT they are engineered and designed to operate at 12 volts nominal and like they say NO BALLAST REQUIRED

ALSO you can buy a coil labeled "6 volts" orrrrrrrr "12 volts FOR USE WITH ballast resistor" orrrrrr "12 volts requires ballast" AND GUESS WHAT!!! THOSE ARE ALL IN REALITY 6 VOLT COILS

SOOOOOOO on a 12 volt tractor you can use EITHER

a) A 12 volt coil

orrrrrrrrrrrrrrrrrrrrrrr

b) A 6 volt coil PLUSSSSSSS an external series voltage dropping (12 to 6) ballast resistor

Get it???? Its NOT really rocket science, post back any questions, hope this answers your great questions

best wishes and God Bless

John T
 

[John T]

Usually (like on the later 620) the ballast was mounted on the back of the steering pedestal, NOT on the coil HOWEVER in all my years of used tractor dealership I SAW ABOUT EVERYTHING LOL

NOTE; A reason for using the 6 volt coil on a 12 volt tractor was to improve cold weather starting, but the tractor had to have the ballast by pass circuit/system to make that work ya know !!!!!!!! The later 620 etc had such

Hope this helps, best wishes n God Bless, fun discussion

John T
 

[John T]

THANK YOU kind sir,

John T
 

[gunther9]

Thanks everyone for the input. I bought this tractor in September 2012 and it had the 6V coil with the ballast resistor. I haven't had the flywheel cover off yet so I don't know if the starter has the terminal to shoot 12V directly to the coil or not. If not, I may get a switch with the side terminal keep the 6V coil and set it up for the 12V kick when starting.
 

[Rich Duane]

John T,
At serial number 6043000 according to the parts book they started using the bypass ignition and resistor like the 620 and 630 tractors.
Rich