Wells-Gardner D9100 - Manual (Page 18)

8-5 Horizontal deflection output stage:
8-5.1 Line driver stage.
As a driver device, small MOSFET Q307(IRF630A) is used.
The driver transformer T302 is equipped with a snubber circuit (R327/C309) at the
primary side to damp excessive ringing.
8-5.2 Horizontal power output stage.
The horizontal power output stage is a conventional one with a diode modulator.
As a deflection transistor, the Q302 (KSC5802/3) is used. To compensate for
horizontal linearity, T301 is connected in series with the horizontal DY. It is controlled
by DC voltage of Q304 collector, which the base voltage of Q304 is integrated from
output at pin 40 of IC601.
8-5.3 S-Correction capacitor switches.
Q316 is off when horizontal frequency is 35KHz
Q316, Q317 is off when horizontal frequency is 37KHz
Q316, Q318 are off when horizontal frequency is 43KHz-52KHz
Q317, Q318 is off when horizontal frequency is 53KHz ∼ 61KHz
Q316, Q317, Q318 is off when horizontal frequency is 62KHz ∼70KHz
Q316, Q318 is off when input is override condition
8-6 FBT (Flyback Transformer):
The high voltage for CRT anode focus, G2 voltage for CRT and – 12V for vertical
deflection are generated by the FBT. Also, -130V for G1 voltage, horizontal flyback
pulse, +120V video supply, and for dual focus units 450V dynamic focus supply.
8-7 ABL (Automatic Beam Limiting):
The voltage of point 7 depends on the anode current of FBT. So, the voltage at pin 7 of
the FBT decreases with increasing anode current. That time, using at this level,
increase contrast setting level limited a certain level (300
µA in white pattern) that is set
by inner voltage of IC401.
8-8 Video amplification section:
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