What was found
ON TAKEOFF ROLL, APU OFF, ENG BLDS ON, PACKS ON (NORMAL CONFIG) SMOKE IN CKPT. NO SMOKE OBSERVED IN CABIN. ABORTED T/O WITH NORMAL BRAKING. REMOVED AND REPLACED NR 1 ENGINE IAW MTX WORK CARD 71-000-00, OPS CHECK GOOD AND LEAK CHECK GOOD. NO DEFECTS NOTED. RAN ENGINE IAW WC 72-700-00. NO SMOKE DETECTED IN CABIN AIRCRAFT RETURNED TO SERVICE.