Farmall Cub

I have a 1951 super C that wont charge, the ampmeter shows a small discharge I am almost posative that the voltage regulator is in working condition.
The output voltage on the generator is 1.7VDC. I have cleaned the comunicator (AKA armature) with no change in voltage. Even tryed to polarize the generator and that has made no diffrence.Should I think about rebuilding the generator or replace it, maybe just change out the brushes??

Any Ideas Or hints would be Greatfully Appriciated!!!

Thanks!

FYI this is a 6Vdc pos grounded system.

I am certainly interested in fixing anything on a tractor that I think I can. But, sometimes it is prudent to use outside help to make the repairs quickly and correctly. To me a non-working charging system is a no brainer to ask for help. Anytime I have a charging problem, I take the genny and VR to an old time shop. He will only repair what he thinks needs to be replaced and then test it. Most of the time he will charge around $40-50 for this service. I would much rather do this than fret with trying to repair it myself and removing it from the tractor several times. JMHO