What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED: DESCENDING THRU 9000 FT CAPTAINS DISPLAY UNIT FAILED THEN CAME BACK ON BUT SIDES WERE REVERSED WITH NAV DISPLAY, FOLLOWED BY A STRONG ELECTRICAL SMELL. THE AIRCRAFT LANDED SAFELY CLT WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE CAPTAINS DISPLAY UNIT PER AMM 31-63-22 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK. (AALA202303158181) WHILE TROUBLESHOOTING THIS EVENT MAINTENANCE FOUND VENT BLOWER AND VENT EXTRACT FAULT STATUS MESSAGES. MAINTENANCE REPLACED CONTACTOR 8HQ PER ESPM 20-45-24 (AALA202303155107) AND REPAIRED A BROKEN WIRE ON CONTACTOR 7QH PER ESPM 20-53-55. (AALA202303154298). A SATISFACTORY OPERATIONAL CHECK OF THE AVIONICS EQUIPMENT VENTILATION SYSTEM WAS ACCOMPLISHED PER AMM 21-26-00 WITH NO FAULTS NOTED.