What was found
DECLARED EMERGENCY DUE TO CABIN ALTITUDE WARNING. PERFORMED PHASE 1 AND QRH. RETURNED TO FIELD. THE RIGHT PACK WAS OFF AT THE TIME, DUE TO RUNNING THE CABIN ALTITUDE HOT QRH MOMENTS BEFORE. TROUBLESHOT, PER FIM 21-30 FAULT TREE 802. UPON DISCOVERY FOUND THAT THE CABIN ALTITUDE PRESSURE COMPUTER (M119), THE NO FAULT LIGHT DID NOT ILLUMINATE, AND THE LRU DID NOT COMPLETE THE BITE TEST. REMOVED AND REPLACED NR 2 CABIN PRESSURE CONTROLLER, IAW B757 AMM 21-31-02-4. OPERATIONS CHECK GOOD. A/C OK TO CONTINUE.