What was found
OPERATOR PURCHASED AN 'EXCHANGE' MAIN ROTOR TRANSMISSION FROM AMERICAN EUROCOPTER. UNIT RECEIVED WITH HISTORICAL RECORD CARDS, A 'SERVICABLE' TAG, AND A FAA FORM ONE CERTIFICATE. TRANSMISISON WAS OVERHAULED 2-4-97, FAA REPAIR STATION ZF6Y043N. AFTER INSTALLATION AND DURING GROUND MAINTENANCE RUNS AND PREPARATION FOR MAIN ROTOR SYSTEM TRACK AND BALANCE CHECKS, DISCOVERED THE TRANSMISSION HAD BEEN ASSEMBLED WITHOUT THE INSTALLATION OF P/N 105-41901.19, BALANCING SYSTEM MAGNETIC PICK-UP 'TARGET'/INTERRUPTOR. SUBMITTER STATED ALTHOUGH NOT A HAZARDOUS SITUATION IN ITSELF, 'WHAT ELSE WAS NOT INSTALLED OR INSTALLED INCORRECTLY?'