As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNKNOWN SOURCE OF AN ELECTRICAL ODOR AROUND THE APU PANEL. NO TRIPPED CIRCUIT BREAKERSS OR OTHER ISSUES NOTED. MAINTENANCE FOUND THE APU SHUNT BURNED IN THE APU RELAY BOX. R & R THE APU SHUNT. INSTALLED A NEW SHUNT IN REVERSE. OPS CHECKED APU IAW MM 49-00-00, SEC 5. NO DISCREPANCIES NOTED.