What was found
ON FLIGHT 3971, CREW REPORTED DURING CLIMB NR 1 ENGINE LP VIBRATION CLIMBED RAPIDLY TO MAX VIBRATION. NO PHYSICAL VIBRATION BY EITHER FLIGHT CREW MEMBER OR FLIGHT ATTENDANT WAS NOTICED. CREW PERFORMED AOM EMERGENCY CHECKLIST AND SHUTDOWN NR 1 ENGINE AS A PRECAUTION. CREW DECLARED A EMERGENCY WITH ATC. AIRCRAFT RETURNED TO MIA AND LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REMOVED AND REPLACED ENGINE VIBRATION MONITOR CONTROL MODULE. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.