Abstract: A CRT display apparatus having an FBT amplifying an inputted voltage and outputting the amplified voltage to an anode of a CRT, a vertical regulator to regulate a V-size of a screen, and a vertical deflector to vertically deflect a scanning line, further comprises a brightness change sensor to sense a voltage applied to an input terminal of a secondary induction coil provided in the FBT, and to output a sensed signal to the vertical regulator; and a brightness change compensator to output a compensating value to the vertical regulator based on the voltage applied to the input terminal, a frequency of the scanning line, and a specification size of the screen to compensate a brightness change. With this configuration, a V-size fluctuation due to a brightness change is minimized in the CRT display apparatus.

Abstract: A CRT display apparatus having an FBT amplifying an inputted voltage and outputting the amplified voltage to an anode of a CRT, a vertical regulator to regulate a V-size of a screen, and a vertical deflector to vertically deflect a scanning line, further comprises a brightness change sensor to sense a voltage applied to an input terminal of a secondary induction coil provided in the FBT, and to output a sensed signal to the vertical regulator; and a brightness change compensator to output a compensating value to the vertical regulator based on the voltage applied to the input terminal, a frequency of the scanning line, and a specification size of the screen to compensate a brightness change. With this configuration, a V-size fluctuation due to a brightness change is minimized in the CRT display apparatus.

Abstract: A device for coding an error generated in processing sync signals is adapted to code an error caused the incompatibility between a video card and a display monitor so that the user can analyze the cause of the error in the sync signals more effectively from the error code displayed on an OSD display. The device includes: a microcomputer responsive to horizontal and vertical sync signals generated by a video card for discriminating resolutions, and coding an error signal into an error code during discrimination of the resolutions; and an error code section for saving the error code received from the microcomputer.