Re: help with 12 volt conversion

Posted by farmallhal on January 04, 2005 at 11:14:39 from (216.106.33.19):

In Reply to: Re: help with 12 volt conversion posted by jeff smith on January 04, 2005 at 07:08:58:

Jeff, First clarify what you are making this conversion on. You talk about a key switch, solinoid and a voltmeter all of which weren't normally installed on a letter series Farmall.
The ballast resistor needs to be in the hot circuit from the on-off or key switch which runs directly to the coil providing battery current through the coil to the points. Its function is to reduce the battery current from 12 volts to 6 volts for the balance of the ignition system. Sounds like you might have it in the wrong wire. The wiring diagram I used doesn't show the ballast resistor in anything connected to the alternator. My tractor only has an ammeter and no voltmeter and I don't know where it would be wired into the system but would think in one of the circuits coming out of the alternator. You mention you have a couple of wires that are hard to get to but you are going to have to know where they run in order to get this correct. I'm also assumming you have changed your ground from a positive to negative by now? The key switch and solinoid shouldn't really play much of a problem but a battery cable from the battery + terminal should run to the solinoid and continue on to the starter. You should also have a battery cable from the battery - terminal running to a good ground on the tractor. You should have a wire running from the battery + terminal or where the battery cable attaches to the the solinoid to the ammeter and on to the key switch so when the switch is in the start or run position you have 12 volt current to the coil through the ballast resistor. I was able to use my existing wire harness which was on the tractor with the 6 volt generator system by just a little rerouting and splicing some extra lengths in a couple of places.
I would suggest you get a new or another battery off of one of your other vehicles until you get this straightened out. Sounds like your battery is not that good and is most likely not the culprit but elminating all possible problems makes this an easier task. I think I would also remove the voltmeter as well for now and add it back in later if you feel you need it. I would also suggest you get the light out of the circuit and replace it with one of those 10 ohm - 10 watt resistors from Radio Shack I mentioned in my earlier post. If you want a light put it back in once you get this thing working as the light might not be providing enough draw to start the alternator to charge. Put as small a pulley as you can find on the alternator so it spins up quicker. You might have been there already with the correct wiring but if your alternator won't start charging you would never know. I would suggest you get this as simple to the original as you can until you have it working correctly and then start adding stuff (light and voltmeter) back in if you feel you want or need them.

Bob Melville who has provided you a couple of posts on this problem was a tremendous help to me along with another person in New York. It sounds like you might be trying to do some stuff which isn't in his wire diagrams which could really confuse the conversion. I'll try and help you as much as I can on this and will keep checking my mail for responses from you but we may have to get Bob involved if this can't get straightened out. One thing about this group of guys on the forum they are all willing to provide whatever assistance they can. Hang in there and it will come home shortly. Hal

Follow Ups:

• Re: help with 12 volt conversion Jeff Smith 12:11:08 01/04/05 (7)
  • Re: help with 12 volt conversion farmallhal 13:16:41 01/04/05 (6)
    • Re: help with 12 volt conversion jeff smith 16:25:34 01/04/05 (5)
      • Re: help with 12 volt conversion Brad A 07:37:00 01/09/05 (0)
      • Re: help with 12 volt conversion farmallhal 19:04:14 01/05/05 (0)
      • Re: help with 12 volt conversion farmallhal 18:19:19 01/04/05 (2)
        • Re: help with 12 volt conversion Jeff in Mass 15:59:01 01/09/05 (1)
          • Re: help with 12 volt conversion Jeff in mass 08:47:21 01/12/05 (0)

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