TELEVISION RECEIVER WITH PROVISIONS FOR SPOT BURN PROTECTION AND AFTER-GLOW SUPPRESSION

摘要

A television apparatus includes a kinescope having a highvoltage supply (B+), a deflection circuit (86), a cathode driveramplifier (84) and a control circuit (82) for controlling operatingmodes of the receiver. A first means (TR17) responsive to a turn-offcommand signal (STBY) from the control circuit (82) disables the highvoltage supply (B+) and initiates turn off of the deflection circuit (86)at a controlled rate. Concurrently, a second means (DRl0,DRl1)responsive to the turn-off command (STBY) applies a turn on drivesignal to at least one electron gun of said kinescope for discharginghigh voltage therefrom. Advantageously, during turn-off the highvoltage is drained from the kinescope as the displayed rastercollapses thus providing benefits such as (1) the safety feature ofhaving a fully discharged kinescope, (2) avoidance of kinescope spotburn and (3) prevention of kinescope after-glow.