What was found
ORD FLT 269 - LAS TO YYZ. WHILE AT FL 370, EXPERIENCED AN ENGINE ONE COMPRESSOR STALL. ABOUT 30 MINUTES LATER, THE NUMBER ONE ENGINE STALLED AGAIN. FLIGHT DIVERTED INTO ORD AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED ENGINE ONE SEVENTH STAGE, LOWER RIGHT (7B), BLEED VALVE. OPERATIONALLY CHECKS OK.