As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 426 FROM CVG TO DAL. AT THE GATE PRIOR TO DEPARTURE, CREW SMELLED SMOKE AND HEARD CIRCUIT BREAKER POP. CREW SHUT DOWN APU AND REMOVED EXTERNAL POWER AND DECLARED AN EMERGENCY. NO FIRE WAS NOTED. FOUND LAV PUMP MOTOR INOP AND LAV MOTOR CIRCUIT BREAKER POPPED. VERIFIED NO FURTHER DAMAGE. PLACED ITEM ON MEL 38-2. AIRCRAFT RETURNED TO SERVICE.