What was found
A LOUD BANG WAS HEARD BY CREW FROM NOSE GEAR AREA DURING GEAR RETRACTION. AN EMERGENCY WAS DECLARED AND FLIGHT WAS RETURNED TO DFW. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE LEFT NOSE GEAR DOOR ACTUATOR AND CABLE BROKEN. ALSO, FOUND DOOR BENT. REPLACED LEFT FORWARD NOSE GEAR DOOR, ACTUATOR AND CABLE, OPERATIONAL CHECK NORMAL.