As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THE EXIT LIGHTS BLINKING - HIGH PITCH SQUEAL WHEN LIGHTS FLASH FROM SPEAKERS IN FIRST CLASS AND FRONT ROWS OF COACH. EMERGENCY LIGHTS OVER FRONT CABIN DOORS DID NOT COME ON WITH PEDESTAL SWITCH ON. MX R & R FORWARD EPSU BATTERY LT AND PERFORMED CIDS RESET. OPS CHECK GOOD. REF AMM 33-51-38-400-002A.