What was found
AFTER ENGINE START NUMBER 1 ENG VIB MONITOR INDICATION WAS OBSERVED WITH READING (BLANK) NO INDICATION. NUMBER 2 INDICATION 0.2. THE ENG VIB MONITOR CB ON P6 2 A 2 WAS VERIFIED IN. THE NUMBER 1 INDICATION RETURNED TO NORMAL DURING TAXI. ACCOMPLISHED FIM TASK 77 05 00 810 805 F00. VERIFIED CDS'S DEU AND AVM FAULTS HISTORY SHOWS 'N2 TACH SIGNAL LOSS'. REPLACED N2 SPEED SENSOR IAW AMM 77 11 02 PAGE BLOCK 401. ENG RUN AND LEAKS CHECK GOOD. NR 1 ENG EEC BITE NORMAL. CDS BITE NORMAL. AVM BITE NORMAL.