As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STL - AFTER TAKEOFF WHEN ENGINE POWER WAS RETARDED TO CLIMB EPR, BOTH MASTER F/W LIGHTS ILLUMINATED AND F/W BELL ACTIVATED WITHOUT ANY FIRE. RETURNED TO STL. REMOVED AND REPLACED FIRE DETECTION AND WARNING MODULE. OPS CHECK AND F/W SYSTEM TESTS GOOD ON GROUND.