What was found
DURING MAINTENANCE GROUND RUNS, STARTED NR 1 ENGINE AND NR 2 ENGINES TO PERFORM REQUIRED MAINTENANCE CHECKS AFTER INSPECTION OF AIRCRAFT AND ENGINES. SHUTDOWN ENGINES TO MAKE TAILROTOR BLADE WEIGHT CHANGE. ATTEMPTED TO START NR 1 ENGINE AND IT WOULD NOT TURN. ATTEMPTED TO MANUALLY ROTATE COMPRESSOR AND COULD NOT. REMOVED STARTER/GENERATOR AND ATTEMPTED TO TURN COMPRESSOR. STILL WOULD NOT TURN. AFTER ENGINE COOLED DOWN, WAS ABLE TO TURN COMPRESSOR BY HAND AND HEARD TURBINE RUB. HP TURBINE DISK IS RUBBING. CHANGING MODULE 2 AND 3 OF EFFECTED ENGINE. PILOT REPORTED NO ABNOMALIES DURING FIRST RUN OF NR 1 ENGINE.