What was found
PDX- RETURNED TO FIELD DUE TO RUDDER PRESSURE, RUDDER FULL PRESSURE AND NR 1 RUDDER HYDRAULIC CAUTION LIGHTS ILLUMINATED AFTER TAKEOFF. AIRCRAFT LANDED WITHOUT INCIDENT. INSPECTED, CLEANED AND RESECURED CANNON PLUGS FOR NR 1 & 2 RUDDER PRESSURE REGULATOR SOLENOID VALVE AND NR 1 & 2 RUDDER ACTUATOR ISOLATION SOLENOID VALVE. NO PARTS REPLACED. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.