What was found
(CAN) THE FLIGHT CREW REPORTED THAT, UPON APPLYING TAKEOFF POWER PRIOR TO ROLLING, THERE WAS A SIGNIFICANT VIBRATION FROM THE NR 1 ENGINE, WITH ACCOMPANYING WHINING NOISE. AFTER SELECTING START/FEATHER ON THE CONDITION LEVER, THE VIBRATION CONTINUED AND COULD BE FELT THROUGH THE POWER LEVER UNTIL SHUTDOWN. INVESTIGATION REVEALED THAT THE BLEED AIR PRECOOLER HAD FAILED, AND THE ECAPING BLEED AIR WAS BLOWING ON THE ENGINE CONTROL CABLES, PRODUCING THE VIBRATION FELT IN THE LEVERS, AS WELL AS THE WHINING NOISE. THE PRECOOLER WAS REPLACED.