If your TV or ham radio antenna rotor stops functioning or operates abnormally, it probably needs repair. Various companies repair antenna rotor units. You can also repair it yourself if you have skill in repairing electronics.
The manufacturer documentation for a Radio Shack TV antenna rotor indicates that only qualified service personnel should perform repairs. It states that service personnel ought to conduct adequate testing and avoid using replacement parts that compromise safety.
If the antenna rotor remains under warranty, contact the manufacturer. Otherwise, try to find a local electronics store or repair shop that will fix it. Another option is to use one of the Internet-based companies which service and return rotors sent in by mail.
If you attempt to fix the antenna rotor, check the owner's manual; it may list part numbers and troubleshooting steps or provide a wiring diagram. If the manufacturer won't supply rotor replacement parts, look for third-party suppliers online.