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CIRCUIT DESCRIPTION
Please use the Commonly Used Shutdown Detection Circuits for the description of how the circuit works.
9. 120V Deflection Power Supply (RP17, QP02, DP15, DP16 and DP18)
If an excessive current condition of the Deflection B+ were detected by RP17, a 0.47 ohm resistor, the
base of QP02 would drop. This would turn on QP02 and the high produced at the collector would fire
zener DP15. This High would be routed through DP16 through DP18 to the gate of the Shut down SCR
QP01 and Shut Down occurs.
10. 28V Vertical IC I601 Power Supply (R645, Q609, D615, and DP34)
If an excessive current condition of the Vertical B+ were detected by R645, a 0.68 ohm resistor, the base of
Q609 would drop. This would turn on Q609 and the high produced at the collector would be routed
through D615 through DP34 to the gate of the Shut down SCR QP01 and Shut Down occurs.
VOLTAGE TOO HIGH DETECTION
Please use the Commonly Used Shutdown Detection Circuits for the description of how the circuit works.
11. Excessive High Voltage Detection (DH31, RH54, RH55 and DH24) Sensed from the Heater
Voltage generated from pin (5) of the Flyback Transformer TH01.
Also, (DH42) sends a high com-
mand to the Horizontal Driver IC IH02, to defeat Horizontal Drive output, the Flyback Transformer TH01
generates a pulse called Heater. (Note: This does not go to the CRTs as heater voltage, it is used for Exces-
sive High Voltage Detection). If this voltage goes too high indicating an excessive High Voltage condition, the
voltage divider comprised of RH54 and RH55 would impress a high on the cathode of DH31. This high is
routed through DH34 to the gate of the Shut down SCR QP01 and a Shut Down occurs.
12. Side Pincushion failure generating a High. (D754, and D753)
The Side Pin Cushion circuit is comprised of I651, Q652 through Q657 If a problem occurred in this circuit
that creates a High on the cathode of D754, the High will be routed through D753 to the gate of the Shut
Down SCR QP01.
13. Deflection B+ Too High. (DP17, RP21 and RP22
RP21 and RP22 form a voltage divider. The top side of RP22 is monitored by DP17. If this voltage goes
too high, the zener DP17 will fire. This high is routed through DP18 to the gate of the Shut down SCR
QP01 and Shut Down occurs.
14. Heater Voltage from the Deflection Power Supply Too High Detection. (DP27 and DP28)
The Heater Voltage for the CRTs filament is generated in the Deflection Power Supply. This voltage is
monitored by DP27. If this voltage goes too high, the zener DP27 will fire. This high is routed through DP28
to the gate of the Shut down SCR QP01 and Shut Down occurs.
