What was found
ON TAXI OUT NR 1 ENGINE HAD A LOW PITCH RUMBLE LOUDER THAN NORMAL. ON T/O NR 1 ENGINE HAD LOUD BANGING COMPRESSOR STALLS ABORTED T/O AT ABOUT 40 KNOTS AIRCRAFT ON TAXI WAY REPORTED FIRE COMING OUT OF BACK OF NR 1 ENGINE. COMPRESSOR STALLS BEGAN JUST PRIOR TO RED. POWER SETTING OF ABOUT 85. NO INLET OR EXHAUST DAMAGE NOTED EEC BITE PER FIM 73 00 801. SHOWS NO RECENT FAULTS. HAND TURN OF NR 1 ENGINE FAN BLADES NOTED INTERNAL DRAG. PERFORMED ACTUATORS TEST PER AMM 71 00 00 700 807 DURING DRY MOTOR EXTREME VIBRATION NOTED FROM NR 1 ENGINE (NR 566116016). REPLACED NR 1 ENGINE PER T/C 78471000 REF W/O 111441. NO DEFECTS OR VIBRATIONS NOTED.