What was found
DURING CRUISE AT 33,000 FEET, CABIN PRESSURE ANNUNCIATOR LIGHT ILLUMINATED. CABIN ALTITUDE ROSE ABOVE 10,000 FEET AND OXYGEN MASKS WERE DEPLOYED THROUGHOUT THE CABIN. EMERGENCY DESCENT WAS INITIATED AND FLIGHT DIVERTED TO GSP. REPLACED THE CABIN PRESSURE CONTROLLER AND AMPLIFIER. OPERATIONAL CHECK OK, AIRCRAFT RETURNED TO SERVICE.