Fault diagnosis method of television camera apparatus

A fault diagnosis method of a television camera apparatus. A fault diagnosis of a television camera apparatus is divided into a plurality of diagnosing processes, and when the result of the fault diagnosis in each fault diagnosing process is diagnosed as abnormal, the fault diagnosis of the next fault diagnosing process is not executed. A microprocessor is provided in each of a camera head and a camera control unit, and each microprocessor independently executes the fault diagnosis and transmits the result of the fault diagnosis to the other. The camera head and the camera control unit constituting the television camera apparatus are connected with each other by a transmission line, and a test signal for diagnosis generated and transmitted by the camera head is received by the camera control unit so that the test signal for diagnosis so received is compared with an expected value corresponding to this test signal so as to execute the fault diagnosis. In the television camera apparatus having such a construction, a plurality of kinds of test signals for diagnosis are prepared in advance, and when these test signals are transmitted, information associated with each test signal is transmitted in combination. Comparison is then made between each test signal for diagnosis so received and the expected value corresponding to this test signal, and various fault diagnoses of the television camera apparatus are executed.