Farmall H 6 Volt Voltage Regulator - Resistor on F

Posted by Ed McCullough on May 21, 2006 at 12:19:10 from (71.162.33.196):

With the help of John Nordhoff's excellent Non Charging Troubleshooting Procedure obtained in a posting in this forum, I have isolated the non-charging issue (I think) with my 1949 Farmall H to a failed resistor which is in series with the field terminal on the 6 volt 4 wire voltage regulator.

When I grounded directly from the field terminal on the generator to the tractor frame, and after polarizing with engine running by briefly jumpering from Armature post on generator to BAT terminal on regulator, a small spark was seen and charging rate of ~10 amps was indicated. Removing the direct ground results in complete loss of indicated charge. A charging state cannot be obtained by directly grounding the regulator saddle bracket to the tractor frame. The resistor believed to be the problem is marked "1 ohm - NEXCOR - 9650", but a check across the resistor with a multimeter indicates an open circuit rather than a small resistance. My conclusion is that the generator is OK, but the regulator (specifically the resistor) is the culprit.

My question: What are the potential negative impacts of simply removing the 1 ohm resistor and attaching the wire directly from the generator field terminal to the "F" lug on the regulator (without the 1 ohm resistor in between.) As can be seen by examining the rightmost terminal in the attached photo, this would result in a direct path to ground from the generator field post.

Alternately, if the resistor is necessary, where might one look to find a replacement? If available, it will certainly be more cost effective to replace the resistor than the entire regulator, but it is often difficult to come by small replacement parts such as this.

Another issue I am dealing with is that all that is available locally is a 3 wire regulator. I am replacing a 4 wire unit, and I would prefer to avoid a rewiring exercise to run lights from the ammeter output rather than the "L" terminal on the regulator.

Thanks!

Replies:

• Re: Farmall H 6 Volt Voltage Regulator - Resistor Ed McCullough 19:37:04 05/25/06 (0)
• Re: Farmall H 6 Volt Voltage Regulator - Resistor gene bender 23:30:26 05/21/06 (0)
• Re: Farmall H 6 Volt Voltage Regulator - Resistor John T 18:52:11 05/21/06 (0)
• Re: Farmall H 6 Volt Voltage Regulator - Resistor Bob M 13:03:51 05/21/06 (0)

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