What was found
INSPECTION TYPE:NA*ATB* CLIMBING THRU 30,100 A/C BEGAN TO SHAKE. FELT LIKE IT WAS COMING FROM THE TAIL. SLOWED DOWN FROM 302 TO 290. THEN 280 KTS. LEVEL AT FL 320, VIBRATION LESSENED BUT DIDNT DISSIPATE COMPLETELY. DESCENDING THROUGH 14,500 VIBRATION INCREASED AND COULD BE FELT THROUGH RUDDERS AND CRTL COLUMNFOUND RUDDER WOULD MOVE AND CHATTER WITH YAW DAMP SYS 1 ENGAGE REMOVED AND REPLACED YAW DAMP ACTUATOR IAW AMM 22-23-22 OPS 2 LH CK GOOD REF LP 639185 ITEM #3