What was found
PILOT REPORTED EXCESSIVE CABIN VIBRATION AT FULL POWER WHILE ON THE GROUND. VIBRATION SUBSIDED IN A HOUR AND THROUGHOUT THE FLIGHT ENVELOPE. DISASSEMBLY AND INSPECTION REVEALED 1 OF 3 SPRINGS IN VIBRATION ABSORBER OF MAIN ROTOR CRACKED ALL THE WAY THROUGH. COMPLIED WITH 2500 HR INSPECTION OF VIBRATION ABSORBER JAW MFG MAINT WORK CARDS AND SERVICING RECORDS. REPLACED ALL 3 SPRINGS AND PN EN2023R12L. BEARINGS WHICH HAD EXCESSIVE PLAY. REINSTALLED AN AIRCRAFT AND VIBRATION WAS ELIMINATED. (K)