What was found
CABIN PRESSURE WARNING LIGHT ILLUMINATED EN ROUTE. CREW EXECUTED EMERGENCY DESCENT TO 23,000 FEET AND CABIN PRESSURE WAS REGAINED. FLIGHT CONTINUED TO DESTINATION AND AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED CABIN PRESSURE CONTROLLER, AMPLIFIER, LEFT COMPRESSOR DISCHARGE THERMO SWITCH, AND AIRSTAIR DOOR SEAL. ALSO, TIGHTENED CLAMPS AT LEFT CROSSFEED VALVE AND FLOW CONTROL VALVE AND REPLACED SEAL AT LEFT SECONDARY HEAT EXCHANGER. LEAK AND OPERATIONAL CHECK NORMAL.