What was found
THE LANDING GEAR HANDLE WOULD NOT RAISE PAST THE OFF POSITION AFTER TAKEOFF FROM EWR. QRH PROCEDURES WERE FOLLOWED AND THE AIRCRAFT WAS RETURNED TO EWR. MAINTENANCE FOUND THE LANDING GEAR LEVER LOCK CIRCUIT BREAKER POPPED. THE CIRCUIT BREAKER WAS RESET. THE GEAR WAS SWUNG SEVERAL TIMES, BUT THE FAILURE COULD NOT BE DUPLICATED. THE LANDING GEAR LEVER LOCK SOLENOID WAS REMOVED AND REPLACED AS A PRECAUTIONARY MEASURE. THE GEAR WAS SWUNG SEVERAL TIMES AGAIN AND ALL OPERATION CHECKED GOOD.