What was found
DEPARTING PHX, EN ROUTE TO SAN, CREW REPORTED DURING LEVEL OFF GOING THROUGH 330 KTS IAS AT 220K FT MSL AIRPLANE SHOOK ON LONG AXIS AT ABOUT 4-10 CYCLES PER SECOND SHAKING STOPPED BELOW 300KTS IAS. AIRCRAFT DECLARED EMERGENCY AND LANDED IN SAN WITHOUT FURTHER INCIDENT. MAINTENANCE TROUBLE SHOT IAW AIRBUS 320 TROUBLE SHOOTING MANUAL 27-34-00-200 AND 05-50-00-810-801. REMOVED AND REPLACED THE RT INBOARD, YELLOW, ELEVATOR SERVO CONTROL PER AIRBUS 320 MM 27-34-51-000-001 AND 27-34-51-400-001. VENDOR CONFIRMED FAILURE. FOUND EXCESSIVE OSCILLATING, AND BOTH SPHERICAL BEARINGS FLATTENED OUT. ALSO FOUND INSULATION RESISTANCE TO LOW. UNIT WAS REPAIRED AND TESTED IAW CMM 27-34-52 REV.9.