What was found
SBA - FLIGHT 2455 - AILERON TRIM MOVING RIGHT WING DOWN SIMULTANEOUSLY WITH RUDDER TRIM MOVING NOSE RIGHT, WITHOUT PILOT INPUT. ON GROUND, CANNOT MOVE AILERON TRIM TO FULL LEFT WING DOWN OR RUDDER TRIM TO FULL NOSE LEFT. AFTER SHUTDOWN AILERON TRIM CONTINUES TO MOVE AT A VERY SLOW RATE. RIGHT WING DOWN AND RUDDER TRIM CONTINUES TO MOVE AT A VERY SLOW RATE, NOSE RIGHT. AIRCRAFT LANDED SAFELY. REMOVED AND REPLACED NR 2 DCU. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.