REMAINING HIGH CRT-VOLTAGE PREVENTING DEVICE FOR DISPLAY DEVICE

PROBLEM TO BE SOLVED: To provide a remaining high CRT-voltage preventing device which can be simplified and can reduce a circuit space or the number of parts. SOLUTION: In the case of power source off (step a-2), a set value BMAX of maximum brightness is sent through a bus line to a video signal processing circuit under the control of microcomputer, bright control is turned into maximum, a beam current flows to a display tube when a power source is turned off, the internal energy of display tube CRT is consumed, and a high voltage is speedily lowered (steps from a-3 to a-7). When turning on the power source again, since the bright control is already returned to user setting B0 (step a-7), ordinary picture display is enabled although energy is discharged by switching setting to maximum brightness.