No franchisee or any major stockholder of a franchisee shall directly or indirectly engage within the city in the business of selling, leasing, renting, servicing, or repairing radio or television sets or other receivers or parts thereof which make use of standard broadcast entertainment signals; provided, that nothing herein shall prevent a franchisee from making modifications to the tuner input circuit of the subscribers’ television receivers and the fine tuning of the subscribers’ operating controls only, to ensure proper operation under conditions of cable connection at the time of installation or in response to subscriber complaints, or from the selling, servicing, or repairing of receivers and other equipment belonging to other cable system operators for use in the conduct of their business. [Ord. 1998-09-075; Ord. 8999 § 52, 1981].