What was found
VIBRATION ON RT SIDE OF ACT, DID NOT FEEL IT BEHIND FIRST CLASS. WHILE STARTING BOTH ENGINES, FELT VIBRATION ONLY ON FIRST OFFICER`S SIDE OF THE FLT DECK. VIBRATION WENT AWAY DURING TAXI & TAKEOFF. IN CLIMB, FELT VIBRATION ON F/O SIDE OF FLT DECK ONLY. VIBRATION STOPPED AFTER LANDING. NO ABBNORMAL EICAS MESSAGES. ALL PARAMETERS NORMAL. RAN NR 2 ENGINE. NO NOISE OR VIBRATION NOTED. ENGINE PARAMETERS NORMAL IAW AMM 05-51-38-202-001. AIRFRAME VIBRATION CONDITIONAL INSPECTION PROCEDURE B ITEM 3, APU CONTROL UNIT REQUIRES REPLACMENT. CONTROLLER RECOMMENDED TO HAVE TECHS PERFORM A GVI OF THE APU INLET DOOR COMPONENTS TO ENSURE NO DAMAGE OR ABNORMALITIES EXIST THAT COULD CAUSE THE DOOR TO REMAIN OPEN WITH APU OFF. R & R APU CONTROL UNIT IAW AMM 49-61-05. OPS CHKD GOOD. PERFORMED GVI OF APU INLET DOOR COMPONENTS & FOUND NO DEFECTS, DAMAGE, OR OBSTRUCTIONS IN INLET. OPS DOOR MULTIPLE TIMES WITH NO ISSUES.