As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAX - LEFT ENGINE RPM INDICATOR REPORTED INOPERATIVE AFTER DEPARTURE. AIRCRAFT RETURNED TO STATION WITHOUT INCIDENT. MAINTENANCE REPLACED LEFT ENGINE TACH GENERATOR. ENGINE RPM INDICATIONS NORMAL DURING ENGINE GROUND RUN. AIRCRAFT RETURNED TO SERVICE. (X)