What was found
ON TAKEOFF ENG 2 & 3 WOULD NOT MAKE MAX TAKEOFF THRUST. ENG FAIL LIGHT CAME ON AT APPROX 110 KTS ABORTED TAKEOFF. ALL ENG N1 INDICATIONS WERE WITHIN .6 PERCENT. NO ENG ROLLED BACK. FOUND NR 3 ENG N1 SPD SENSOR ERRRATIC / UNRELIABLE. REMOVED AND REPLACED NR 3 ENG N1 SPD SENSOR AND N1 IND IAW MM 77-11 REF LP 61342, ITEM 5. ADJUSTED FLT IDLE ON NR 2 AND NR 3 ENG IAW MM 73-20. RAN ALL THREE ENGINES IAW JRH & COM. ALL PARAMETERS WITHIN LIMITS. ENG FAIL LIGHT DID NOT ILLUMINATE. SENSOR WAS FOUND TO HAVE CORRODED CONNECTOR AND LOWER HOUSING REQUIRING REPAIR.