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posed of R410,
R411.
R423. C408. and C410. then be applied via C405 to
Pin 4 of 0402.
The
discriminator inside the IC Q402 detects the phase difference
bet-
ween the sync.
input from Pin 3 and the sawtooth-waveforme from Pin 4 .
the
supper imposed pulse outRut from Pin 5 of 0402 is integrated by the
low-pass-filter R407, C404 and C403, AFC voltage is obtained and applied
via R406 to Pin 7 of Q402. thereby controlling the oscillator.
The
oscillator inside IC Q402 is an RC type with Pin 7 used to
control
the timing.
R404,
R405.
R422,
C402 and C410 altogether determine the
horizontal oscillating frequency.
The predriver output of Q402 is at Pin 1 of which duty cycle is control-
led by R402 and R403 at Pin 8 of 0402.
Regulated voltage applied at Pin 6 of 0402 is about 8 - 9 volts.
The
output
signal
from Pin 1 of Q402 is then amplified
by Q401
and
coupled
by T401 to the horizontal output stage Q403 for ON-OFF control,
thus sawtooth-waveform current through the horizontal deflection coil is
obtained.
Also during the retrace time of the horizontal deflection.
a horizontal
flyback
pulse at about 1100 volts is produced at the collector of Q403.
this
pulse is transfered and rectified by the FBT T403 to
obtain high
voltage of about 22.0KV tor anode of CRT.
5-5 DPC CIRCUIT
The
Side Dynamic Pincushion Correction circuit (Side DPC) modulates the
raster width as a function ot vertical deflection.
The
vertical castle-waveform from Pin 1 of 0301 is integrated by C314,
R326,
R327,
R328,
C316 etc. to produce a parabolic waveform necessary
for side pincushion correction,
this parabolic voltage is amplified by
Q302 and
Q303
stages and
then drives the control winding of the satur-
able reactor T402.
The
inductance of the T402 output winding is modulated by the
vertical
parabolic
current.
this output winding is inserted in series with
the
horizontal deflection yoke.
The
horizontal yoke current is th8n modulated by the correction voltage
to correct side pincushion distortion.
5-6 VIDEO CIRCUIT
The color display contains three video amplifiers,
one for each primary
color.
these three amplifiers for the red,
green and blue CRT guns are
:dentical.
Video
amplifier consists of preamplifier
Q501
(H51387P),
output
stage
and cut off adjustment CIrcuit.
The operation of only one channel (blue) is described here.
Analog video signals
IS
preadjusted by R502 and coupling VIA C501.
C502
to input of Q501.
Contrast is DC controlled from Pin 14 of 0501. clamp pulse provided from
Pin 7 of FBT (T403) to PIS of 0501. The output of Q501 is at Pin 21.
7
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