As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON LANDING, STRONG ACRID ODOR IN CABIN AND COCKPIT AREAS. MECHANIC CALLED IN AND UPON INSPECTION OF OVERHEAD CIRCUIT BREAKER PANEL, IT WAS DISCOVERED THAT THE STANDBY ATTITUDE INDICATOR CIRCUIT BREAKER WIRE HAD CONTACTED METAL FRAME RESULTING IN ARCING. MECHANIC TIGHTENED WIRE LUG AT CIRCUIT BREAKER AND ADDED INSULATION ON FRAME. AIRCRAFT RETURNED TO SERVICE.