I recently aquired a 1977 roughneck 2e. have the engine running fair right now, but all at once it quit putting out power. I cleaned the slip rings and brushes to no avail, and discovered I have no power at the brushes. If I jump a wire from the battery to the + brush I get about 20v at the outlet. also I have good continuity at the switches and they seem to be wired up properly but the capacitor is not getting any voltage. which makes me think exciter board. (the fuse link on the board is good.) any advice would be much appreciated.