As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB, THE NR 1 ENGINE COMPRESSOR STALLED. ENGINE STABILIZED AFTER POWER REDUCTION. FLIGHT RETURNED TO STL AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE ENGINE WITH A SERVICEABLE UNIT. ENGINE TEARDOWN ANALYSIS REVEALED INNER COMBUSTION CASE FORWARD FLANGE HAD LIBERATED FROM CASE.