AUTO-DIAGNOSIS
Many videorecorder designs make provision for ‘self-diagnosis’, in which a readout gives information on the cause of the last malfunction or shutdown, either automatically or when the service mode is called up by a technician. This is useful in routine diagnosis, and invaluable when the trouble is intermittent – the fault data is held in memory. An example of a self-test indication display (from the same
Panasonic machine as the diagram of Fig. 16.3) is given now in Fig.
16.8. It is one of a whole series of stored error and malfunction indications which this machine provides for both the user (to report) and the technician: there are seven service modes in total, each addressing a different aspect of deck and control operation.
The auto-diagnostic facilities provided vary between manufacturers. The vital thing is to ascertain that a self-diagnostic function is present and then to find out how to call it up and how to interpret the displayed data. All these are covered in the service manual for the model in question.