What was found
(CAN) PILOT COULD NOT MOVE MLG HANDLE TO RETRACT MLG. TRIED SELECTING GEAR DOWN & WIGGLING HANDLE BUT STILL UNABLE TO RETRACT. PILOT REQUESTED RETURN TO BASE & AFTER AN UNEVENTFUL LANDING NOTICED MLG HORN SOUNDING CONTINUOUSLY, AIRCRAFT BROUGHT TO A STOP ON RUNWAY & MX NOTIFIED TO TOW ACFT FROM RUNWAY. MX PROCEEDED TO RUNWAY, COMPLETED A MLG INSPECTION TO ENSURE ALL 3 GEAR IN A SAFE & LOCKED POSITION THEN TOWED ACFT TO HANGAR. UPON FURTHER INSPECTION MLG ANTI-RETRACTION SOLENOID PLUNGER PIN FOUND BENT & RESTRICTING ITS RETRACTION HINDERING THE SELECTION OF GEAR UP WITH HANDLE. SOLENOID WAS REPLACED WITH A SERVICEABLE SOLENBOID AND F/C. THE AIRCRAFT WAS RETURNED TO SERVICE.