Check earth wire in bottom of right hand console! also do a voltage check on wires near the brush holder on end of clutch. You should get very close to max voltage with engine running at that point! anything less than  a volt or  so, you will need to track down the resistance point. (earths leads and paint on frames can be a pain in the butt.) also take cap of brush holders an blow out crud! as any moisture can play Merry Hell with this stuff!  Rolf