What was found
AIRCRAFT WAS CRUISING AT FL330 WHEN THE CABIN PRESSURE ANNUNCIATOR LIGHT ILLUMINATED AND CABIN ALTITUDE WAS APPROACHING 10,000 FEET. WING ANTI-ICE AND ENGINE ANTI-ICE WERE BOTH ON AT THE TIME AND TURNING THEM OFF DID NOT HELP TO REGAIN CABIN PRESSURE. CREW DECLARED AN EMERGENCY AND DESCENDED TO 10,000 FEET WHERE THE SYSTEM WAS ABLE TO RECOVER. LANDING AT ATL WAS WITHOUT INCIDENT AND MAINTENANCE REPLACED THE PRESSURE CONTROLLER AND THE PRESSURE AMPLIFIER AFTER CHECKING FOR LEAKS. NO LEAKS WERE FOUND AND MASKS DID NOT DEPLOY. AIRCRAFT RETURNED TO SERVICE.