What was found
DURING CLIMB, THE CABIN TEMPERATURE BECAME UNCONTROLLABLE IN AUTO AND MANUAL. UPON REACHING FL 230 THE CABIN PRESSURE WARNING LIGHT CAME ON INDICATING A 10,000 FOOT CABIN. A RAPID DESCENT DOWN TO 8,000 FT WAS INITIATED. THE CABIN BECAME VERY HOT SO THE CREW DEPRESSURIZED THE ACFT AND USED RAM AIR VENTILATION TO COOL THE CABIN TO A COMFORTABLE LEVEL. INVESTIGATION REVEALED THAT THE AIR CYCLE MACHINE WAS SEIZED. THE ACM WAS REPLACED AND THE ACFT RETURNED TO SERVICE. ACM DETAILS: PN 782790-18, SN 870217, TSN 38107, CSN 37231, TSO 2951, CSO 2974.