Abstract: An improvement for effecting rapid warm-up of the thermionic cathode means in a color CRT display device utilizing a degaussing circuit including a temperature responsive resistive element in series with the primary winding of an inductive means. A direct operational relationship is established between the degaussing and cathode heater circuits by having the secondary winding of the inductor series coupled therein. Upon simultaneous activation of both circuits, through a common switching means, a transitory surge of current is supplied by the degaussing circuit to the heater circuit, via the common inductor, to effect an accelerated temperature response in the heater.