What was found
ORD - FLT 916 - ON CLIMB-OUT FROM ORD, EN ROUTE TO CLT, THE NR 2 ENGINE BLEED TRIP LIGHT ILLUMINATED. CAPTAIN TRIED TO RESET THE NR 2 ENGINE BLEED TRIP WITH NO HELP, AS LIGHT REMAINED ILLUMINATED. CABIN PRESSURE STARTED TO CLIMB WITH THE AIRCRAFT, SO THE CAPTAIN DECKED TO RETURN TO FIELD AT ORD. FLIGHT LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. MAINTENANCE REMOVED AND REPLACED THE NR 2 ENGINE HIGH STAGE REGULATOR PER MM 36-11-86. PERFORMED OPERATIONAL TEST OF BLEED AIR CONTROL SYSTEM PER MM 36-11-05. OPERATIONAL TEST GOOD. (M)