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EN 90
9.
DPTV565 AA
9.3.22 High Voltage Circuit
The High Voltage module is an integrated High Voltage supply
with its own switching power supply. When the set is turned
"on", 11.5 volts from the Sweep Failure detection circuit is fed
to diode 6913 and to pin 8 of the High Voltage module. A supply
voltage of 130 volts is also fed to pin 10 of the module. The
Module then outputs High voltage to the three CRTs. It also
outputs Focus voltage to the Focus G2 block. Output on pin 4
is rectified by 6917 to produce a negative 200 Volt source for
the CRT G1 voltage. The voltage is also rectified by 6919 to
9.3.23 Shutdown
The Shutdown circuit will shut the High voltage "off" if the
Horizontal or Vertical Sweep should fail. It will also shut the
High voltage "off" if the Power Fail line goes "high" or the +200
Volt source should fail.
Circuit Descriptions, List of Abbreviations, and IC Data Sheets
Figure 9-29 High voltage circuit
Figure 9-30 Blanking and HV-protection circuit
produce a 375 Volt source for the Dynamic Focus drive. The
DAG line along with the output on pin 2 is connected to 7903 to
produce the ABL voltage for the set. If an over-current condition
should develop with the drive, the ABL voltage will go Low,
turning 7905 "on", latching 7904, which will remove drive to pin
8 of the HVG. This will cause the High voltage to shut "off".
Vertical Parabola drive is fed to 7901 to produce the Vertical
component of the Dynamic Focus drive.
The Vertical pulse is fed to zener diodes 6824 and 6814, which
keeps capacitor 2837 charged. This pulse is rectified by 6815
to keep the base of 7808 at a negative voltage. This keeps the
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