Zenith Electronics Corporation

Zenith Radio Corporation

James J Reno, Jr

Richard G Schmid

A shutdown circuit for a TV projection monitor includes a standby power supply energizing a main power supply through contacts controlled by a relay winding in the load circuit of a control transistor that is cut off by a pair of latch transistors that receive operating power through the relay winding. Closure of a momentary contact switch effectively disables the latch transistors and grounds one end of the relay winding which is thereby energized to enable the main power supply. Disabling the latch transistors permits the control transistor to become conductive and hold the relay winding energized. A subsequent closure of the momentary contact switch applies sufficient potential to the latch transistors to drive them conductive and disables the relay winding for deenergizing the main power supply.

On/off and shutdown circuit for CRT projection system

Heat sink means for a projection television cathode ray picture are disclosed. The tube has a face plate on the inner surface of which is deposited a cathodoluminescent screen for forming a television image. The face plate develops an undesirably high temperature during operation resulting in cracking. The heat sink means according to the invention comprises a heat-conductive panel, which may be a metallic plate, larger in area than the face panel. The panel has a window for passing the television image. The panel is in intimate contact with the face plate for conducting heat from the face plate and inhibiting thermal cracking.

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Schaumburg, IL, United States of America

James J Reno, Jr