What was found
JFK - ABORTED TAKEOFF - FLT 0411 - ON TAKEOFF AT JFK EN ROUTE TO SFO RECEIVED NR 1 IR FAULT, REJECTED TAKEOFF AT 90 KTS. MAINTENANCE ISSUED MEL 34-10-01, COND 2 IRS NR 1 NAV MODE INOP. ON 03/15/2004 MAINTENANCE REMOVED AND REPLACED THE NR 1 AIR DATA INERTIAL REFERENCE UNIT IAW T/C R2A34304, OPERATIONAL CHECK WAS GOOD. VENDORS TEARDOWN REPORT OF ADIRU S/N 0987 CONFIRMED FAILURE OF THE UNIT. FOUND VIBRATION ISOLATORS SPLIT AND THE "Y" MULTI OSCILLATOR LASER GYRO UNMODELABLE. REPLACED MULTI OSCILLATOR LASER GYRO (P/N 517107-2, S/N 407913) AND REPLACED VIBRATION ISOLATORS WITH A MATCHED SET. PERFORMED THERMAL CALIBRATION AND TESTED UNIT IAW CMM TP1011, REV. 23.