6-4
6-3. E Board Descriptions
1. Horizontal System
1-1. H DELAY Circuit
IC621 is composed of the circuit generating the sawtooth
signal which uses the H SYNC of the input signal as the
trigger and the integral circuit. It outputs the signal obtained
by adding the sawtooth signal and parabola signal which syn-
chronize with the input signals. IC622 compares this signal
with the reference voltage and outputs the rectangular wave.
The falling edge is deviated by about 1/4 of the horizontal
period from the input signal. Therefore in the H DELAY
mode, the signals are synchronized after a delay of about 1/4
horizontal period.
1-2. AFC Circuit
IC001 is a CRT driver and performs RGB signal processing,
sync and deflection signal processing.
This unit does not use a RGB signal processing circuit.
The AFC circuit of IC001 compares the phases of the H
SYNC of the input signal input to pin 6 and the pulse of the
horizontal deflection output input to pin $¡. The error signal
is passed through the low pass filter connected to pins $™,
$∞, $§, and $¶ to control the frequency and phase of the
ceramic oscillator connected to pin 44. The functions of IC001
consist of horizontal picture phase adjustment (H PHASE),
horizontal picture size adjustment (H SIZE), horizontal pin
distortion correction (H PIN), trapezoid distortion correction
(H KEY), horizontal bow distortion correction (H BOW),
and parallelogram distortion correction
(KEY BAL).
1-3. Horizontal Deflection Circuit
The H.DRIVE pulse is passed through Q053, T051 (HDT),
supplied to Q054 (H.OUT) to switch Q504 and drive T5002
(HOT) and H.DY.
The power supply of the horizontal output circuit is gener-
ated by IC071 (RWM control) by switching Q061 to improve
the power efficiency. The H PIN/W voltage from IC001 is
input to IC701 to control the power voltage.
1-4. H Center Circuit
Positive and negative power supplies from the secondary side
output of T052 (HOT:Horizontal output transformer) are gen-
erated as the power supply of the H center circuit. In the H
center circuit (IC091, IC101, Q091, D103), the DC current
flowing through the H.DY is controlled by the H.CENT sig-
nal from IC001.
1-5. Landing Circuit
The LANDING voltage output from the D/A converter of
IC201 inside is input to IC231 to control the current flowing
through the LANDING coil.
1-6. NTC Drive Circuit
The NTC signal output from IC201 is amplified by the IC801
to drive the NTC.
1-7. H Linearity Circuit
The H.LIN signal output from IC151 is amplified by Q151
to Q159, T151 (HLT) is driven, and the H linearity compen-
sation current is passed through the H.DY.
1-8. Rotation Circuit (20-Inch Model)
The ROTATION voltage output from IC703 of the D/A con-
verter is input to IC401 to control the current flowing through
the ROTATION coil.
1-9. H Convergence Circuit (20-Inch Model)
The H.CONV correct signal output from IC701 is amplified
by Q721 to Q729 to drive the CY (H).
The H.CONT correct signal output from IC701 is amplified
by IC702 to drive the CY (V).
2. Vertical System
2-1. V DELAY Circuit
IC641 is composed of the circuit generating the sawtooth
signal which uses the V SYNC of the input signal as the trig-
ger and the amplifier circuit. It outputs the signal synchro-
nized with the sawtooth signal. IC622 compares this signal
with the reference voltage and outputs the rectangular wave.
The falling edge is deviated by about 1/2 of the vertical pe-
riod from the input signal. Therefore in the V DELAY mode,
the signals are synchronized after a delay of about 1/2 verti-
cal period.
2-2. V. OSC Circuit
The V OSC circuit of IC001 adopts the countdown method.
It counts the horizontal pulses and resets using the V SYNC
input to pin 5. Its functions consist of the vertical picture size
adjustment (V SIZE), vertical picture position adjustment (V
POSITION), vertical linearity correction (V LIN), and verti-
cal linearity balance correction (V LIN BAL).
2-3. Vertical Deflection Circuit
The V SAW signal output from IC001 is input to IC301 via
the buffer IC (IC091), and to drive the V.DY by IC301.
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