As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OUT WITH ANTI-ICE ON NR 4 ENG COMPRESSOR STALLED. THE CREW RETURNED TO DEPARTURE WITHOUT FURTHER INCIDENT. MX REPLACED NR 4 INBD ANTI-ICE CONTROL VALVE REGULATOR. OPS CHECK GOOD IAW MM 75-10-1. ACFT WAS RETURNED TO SERVICE.