Original Message

Ok...our Mx crew figured it out.  Wasn't the brushes....those are new.  Doing some more troubleshooting and digging into Dunston Notes, turns out there are filter capacitors inside the terminal block of the Start-Gen...then confirmed by testing the filter capacitors.

One of ours is bad (circled in image below).  Unfortunately it sounds like those filter caps aren't readily replaceable and must be dealt with at overhaul.  (note:  I'm not an A&P and am doing my best to regurgitate this). 

Mystery solved and maybe this will help someone else out down the road.