As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT CONTROL TEST, NOTICED A VIBRATION IN CONTROL COLUMN AFTER RELEASING BACK PRESSURE. REMOVED FROM SERVICE. PERFORMED GVI OF CONTROL-COLUMN DAMPER FLUID LEVEL IAW E175 AMM 27-31-02-210-801-A. SERVICED RH CONTROL COLUMN DAMPER IAW E175 AMM 12-21-16-610-801-A. CONTROL COLUMN VIBRATION NO LONGER PRESENT. NO FURTHER DEFECTS NOTED. RETURNED TO SERVICE.