As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PARKED AT THE GATE USING GROUND POWER, SMOKE WAS SEEN COMING INTO THE CABIN FROM THE LOWER ELECTRONIC COMPARTMENT. SHUT DOWN ELECTRICAL POWER. FOUND THE BUS CONTROL PANEL WITH BURNED WIRING. REPLACED THE BUS CONTROL PANEL. CHECK-C 7-6-98 STL.