As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED A LOUD HIGH PITCH NOISE AND ELECTRICAL SMELL IN COCKPIT. AIRCRAFT LANDED WITHOUT ISSUE AND AS SCHEDULED. MAINTENANCE INSPECTED COCKPIT AREA, UNDER FLOORBOARDS, BEHIND CIRCUIT BREAKER PANEL AND IN THE AVIONICS BAY. UNABLE TO FIND ANY DEFECTS. AIRCRAFT WAS FLOWN ON OPERATIONAL CHECK FLIGHT WITHOUT ANY ISSUES. RETURNED TO SERVICE.