7-187.3 Vertical Flyback Blanking CircuitThe V-OUT output from the MPU U701 Pin 32 is synthesized with the vertical deflection output that has beenshaped by the circuit of C409, D402, R415, R414, and C408. The synthesized output is used for the blankingoperation of the vertical flyback period, by switching Q401 that is connected to G1.(Fig. 7.3)Vertical Flyback Blanking Circuit7.4 Blanking Operation: Signal Mode Changeover, Power ON/OFF and Unstate Sync signalsThe image blanking operation at the time of signal mode changeover and power ON/OFF is carried out bycontrolling the G1 voltage. This voltage control is actually effected by Q307 that makes the switching of theblanking pulse output sent from the MUTE1 circuit of the U701 Pin 2 through D310.When the sync signals become unstable, the blanking operation is carried out by controlling the G1 voltage,whose operation is actually effected by Q307 that makes the switching of the blanking pulse output sent fromthe HUNLOCK circuit of the U501 through D311.(Fig. 7.4) Blanking Operation: Signal Mode Changeover, Power ON/OFF and Unstable Sync signalsG1 vertical deflection outputU70132pinT3015pin12VG1U7012pinU50117Pin
