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The Side PCC amplifier produces a correction voltage
which modulates the horizontal deflection yoke current
for the correction of the pincushion distortion at both
sides of the raster.
The Side PCC modulates the horizontal
deflection amplitude as a function of vertical deflec-
tion, and is obtained by applying a parabolic
wave~orm,
derived from vertical scan, to the horizontal
deflection regulator.
This is amplified by the horizontal
deflection regulator and produces a parabolic modulation
of the power supply voltage.
This in effect makes the
scanning lines near the center of the raster longer than
lines near the top and bottom.
The high voltage winding of the flyback transformer
drives a rectifier circuit
to produce 25 KV DC CRT anode
voltage (E.H.T.).
The high voltage is sampled and compared to a constant
voltage, and the differential voltage drives the high
voltage regulator transistor so that a normal high
voltage condition is maintained.
If high voltage become
excessive, the SCR Switches in the HV Safety Circuits
turn on and clamp the input pulse signal used for the
high voltage
drive circuit.
A health check circuit monitors
t~e
nigh voltage
circuit and
tne
hori2~ntai dei~ection
circuit.
Tns rieo.l ti1 Cn.::ck
Indicat:.ur
is illuminac.eu
dUl:.Lll'='
normal
OJ!-.!ration.
The brightness and blanking signal supplied
to
the CRT
control grids is developed
by
mixing the brightness de
voltage from the brightness potentiometer with the
outputs
of
the blanking circuits and the ABL (Automatic
Beam
Limiter)
circuit.
Blanking signal is derived
by mixing and wave shaping vertical and horizontal
deflection pulses.
The brightness potentiometer is
biased by a +lOOV and -86V de regulator.
3-3
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