Intensity Override Control
Original Publication Date: 1980-Feb-01
Included in the Prior Art Database: 2005-Feb-13
In a display terminal, if the screen goes blank it is necessary for the repair engineer to be able to distinguish whether the blank screen is due to a failure of the EHT supply or of the video circuits. To this end it has been suggested that a spring-loaded potentiometer should form the brightness control. During fault analysis, the engineer rotates the brightness control in a clockwise direction out of the normal operating range against the spring loading to invoke the intensity override function. This causes the video to be suppressed and the screen to be brightened. If the screen fails to brighten, this implies a failure of the EHT supply.