I have no charging issue with a 806 Farmall. Has the Alternator conversion. Took alternator off to test it, came back fine. The external regulator was replaced, still no change. Does any one know how that 4 terminal external works with the Alternator?

You need power from the ign switch to kick in the regulator to excite the alt.

Presuming your tractor has a Delco alternator it could be a bad voltage regulator or incorrect wiring. Or if the tractor has a charge idiot light it could be a simple as a burned out idiot lamp. ALSO.... if your alternator is a 10SI (internal regulator) it will NOT work with a tractor wired for an externally regulated (10DN) alternator.

Spotting difference for 10SI and 10DN alternators:

A 10SI has the aux terminal connection on the rear outside edge of the case. The terminals arranged in line: - -

The 10DN connection is on the back with the terminals parallel: I I

See the link for a diagram for an externally regulated alternator.
external regulator wiring

(quoted from post at 17:33:46 02/15/15) You need power from the ign switch to kick in the regulator to excite the alt.

Click to expand...

I have power going to the regulator

(quoted from post at 17:33:46 02/15/15) You need power from the ign switch to kick in the regulator to excite the alt.

Click to expand...

I have power going to the regulator

This I uploaded a photo showing a charging system that my 806 has. Terminal 3 and 4 are ones that have power when key is on, both are showing 12.2 volts.

Check the wiring harness in front of the fuel tank where the wires get close to the manifold pipe, just above the valve cover. I have seen lots of problem with the wiring harness in this location.

I know when it was running I took off the regulator cap and press the field points together it would finally show a charge BUT the points would stick close and turn red hot.

I think you will find that Charlie is correct and you will find the field wire is shorted between the regulator and alternator.

As for how the system works, the voltage regulation relay is normally closed to allow the current flowing through the light bulb and the external resistor to go to the Field terminal on the alternator. Internally in the alternator the F terminal is connected to one brush lead. The power goes through that brush, through the field coil in the rotor turning it into a magnet and out through the other brush to ground. When the alternator starts to charge there is a current supplied from the Relay terminal on the alternator which closes the field relay in the regulator. When that relay closes it provides full battery voltage to both terminal 3 and 4 on the regulator causing the light to go out. It also provides full battery voltage to the voltage relay which will switch from providing battery voltage to the alternator field to grounding the field when the voltage rises to to set level. That causes the alternator output voltage to drop which in turn causes the voltage relay to switch back to providing full battery voltage to the alternator field coil. As the voltage relay points vibrate between battery voltage and ground the voltage is controlled by varying the amount of time between the two positions. The result is that the alternator is switching between full output and no output. This is what messes up some digital meters when trying to check the voltage.

When you manually closed the field relay you caused full battery voltage to go through the voltage relay and out the field wire to the alternator. Since that wire has a short to ground the relay points were overloaded and became red hot. The closing of the field relay is also what turns off the charge indicator lamp by applying battery voltage to both sides of the bulb. Since the shorted wire has less resistance to ground the field coil in the rotor your manually closing the points could cause the alternator to begin to charge a little but the reason the light went out is because with that relay closed the bulb had battery voltage on both sides.

Thank you guys for the info. I was not able to find how the charging system works but I do now.

You CAN get 100 volts out of those alternators by putting full batt. voltage to the field.
Might be the cause of red hot thing.