As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PILOT REPORTED DURING HOVER, THE TAXI LOW ROTOR WARNING ACTIVATED BUT ROTOR RPM WAS IN PROPER AREA OF GREEN ARC ON DUAL TACH. DURING SHUTDOWN, SWITCHING BELT DRIVE ENGAGEMENT SWITCH TO DISENGAGE MADE ENGINE QUIT. TROUBLESHOOTING REVEALED CONTROL UNIT DISCONNECTION REQUIRED FOR ENGINE START AND OPERATION AND CONTROL UNIT HAD FAINT ELECTRONIC BURNED ODOR. SYSTEM DISABLED FOR AIRCRAFT RETURN TO SERVICE.