What was found
DURING CRUISE AT FL 370, PRESSURIZATION SET FOR FL 380 WITH CABIN AT APPROX 7,000 FEET. CREW HEARD A DULL NOISE, CABIN OXY MASK DEPLOYED, MASTER WARN RED LIGHTS AND CABIN ALTITUDE INCREASING. ACFT DIVERTED FOR REPAIR. FOUND FAILED BLEED SYS HOSE AND A NON-RETURN VALVE OUT OF LIMITS AT .75 INCH OPEN.