As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PUSHBACK STRONG SMELL OF ELECTRICAL FIRE, NO VISIBLE SMOKE. RAN ELECTRICAL FIRE CKLIST, STRONG SMELL NEAR F/C FLIGHT ATTENDANT JUMPSEAT. FOUND APU POWER RELAY PHASE A1 TERMINALS BURNT. REPLACED RELAY BASE AND CONTROL. FWD TO MCO/PLAC 49-10-01. APU INOP DUE TO TERMINALS BURNT.