What was found
RUDDER TRIM INOP INTERMITTENT. PER CREW INBOUND CREW, AC REQUIRED FREQUENT RETRIMMING AND AT TIMES, RUDDER TRIM WOULD BE INOP AND OTHERS IT WOULD TRIM NORMALLY, ALL AT CRUISE. OCCURRED ON THE GROUND AS WELL AFTER ARRIVAL. SUSPECT INTERMITTENT TRIM COMMAND FROM CONTROL PANEL. PRIOR TO REPLACING CONTROL PANEL, ATTEMPT (CONT). INTERMITTENT TRIM CONTROL MODULE, NO SHOP DATA. REPLACED AILERON AND TRIM CONTROL MODULES, ALL OPS CHECKS NORMAL.