Self-diagnosis arrangement for a video display and method of implementing the same

A method for self-diagnosis testing of a video display apparatus including a cable connector, a microprocessor, on-screen display means and a cathode ray tube, said method comprising the steps of:

• checking said cable connector to determine connection to an external system;
• generating horizontal and vertical synchronizing frequencies in said microprocessor in case of no connection between said cable connector and external system;
• and
• outputting a self-diagnosis display signal to said cathode ray tube from said on-screen display means responsive to an input signal supplied from said microprocessor.

A video display apparatus including a cable connector to which a signal cable of an external system is engagedly connected, an amplifier for receiving a first video signal supplied via said cable connector and a cathode ray tube for displaying said signal input from said amplifier, said apparatus comprising:

• a microprocessor storing information for an image status being displayed, for selectively switching between internal horizontal and vertical synchronizing signals from an internal generator and external horizontal and vertical synchronizing signals from said external system to provide output horizontal and vertical synchronizing signals having predetermined frequency levels based on a connection status between said signal cable and said cable connector;
• means for supplying a plurality of second video signals corresponding to said stored information provided by said microprocessor to said amplifier;
• and
• horizontal and vertical deflection circuits, responsive to said output horizontal and vertical synchronizing signals input from said microprocessor, for supplying horizontal and vertical deflection signals to said cathode ray tube.