What was found
DURING FLIGHT, EN ROUTE TO YVR FROM PHX, THE CREW REPORTED THE NR 1 PACK OVERHEATED IN FLIGHT, WITH THE NR 2 PACK ALREADY BEING ON MEL. CREW DIVERTED TO LAS AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND THE NR 1 ACM SEIZED. REMOVED AND REPLACED THE NR 1 AIR CYCLE MACHINE IAW AIRBUS 320 MM 21-52-21. OPERATIONAL TESTS WERE GOOD. UNABLE TO CONFIRM FAILURE OF ACM. A FEW ITEMS WERE FOUND REQUIRING REPAIR BUT WOULD NOT HAVE CAUSED FAILURE. UNIT WAS INSPECTED, TESTED AND REPAIRED IAW CMM 21-52-16 REV 3.