As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE RETURNING TO BASE, EXPERIENCED A BURNING ODOR AND SMOKE IN CABIN. SMOKE CLEARED, MADE A PRECAUTIONARY LANDING. AFTER LANDING AND SHUTTING DOWN IT WAS DETERMINDED THAT THE AIR CONDITIONING BELT HAD BROKEN. REPLACED THE BELT AND CLEARED THE ACFT FOR FLIGHT.