Haier HS-2190 Service Manual page 24

signal processing circuit via C/VIDEO electronic switch.
The video signals into the video signal processing circuit are amplified by 6dB gain. Then
one part of the signals are sent to the scanning unit and horizontal and vertical signals are
output through Pin (32) and (24) after horizontal and vertical oscillation.
The other part of the signals is output via Pin (35) to Pin (39) after being followed and
resistance voltage divided for 6dB attenuation by V201. The video signals are input into
carrier wave trap circuit and the color signals are removed. Then they enter the Y/VIDEO
switchover circuit to be sent to the video unit.
C/VIDEO electronic switch outputs video complete TV signals or the color signals to the
band-pass/high-pass filter circuit. The color signals are got out and sent to the chrominance
unit. The R-Y, B-Y and G-Y signals output from chrominance unit are sent to the matrix unit
together with Y signal output from the video unit to generate R, G and B primary color
signals, which are then output via Pin (18) (19) and (20) into the final circuit CRT board to
the picture tube circuit.
Tuning reverse code PWM signals are output from super central microprocessor N901 via Pin
(2). With reverse phase amplification and integrator processing by V975, PWM signals
become D.C. tuning voltage and are added to the tuning voltage input terminal (TU) of the
tuner A\U101. The control signals are output from Pin (9) (10) of N901 into N101 wave band
switchover. The wave band switchover is as follows:
Working
band
VL
VH
U
CATV
(3) External audio and video signal processing
The video input signals are sent into the TV/AV electronic switch via N201 Pin (41) through
XS302 VIDEO IN after being coupled by C230.
The audio input signals are sent into TV/AV electronic switch via N201 Pin (55) through
XS301 AUDIO IN after being coupled by C299. The picture and sound signal processing is
carried out by N201 (TB1238AN).
(4) Sound signal processing
The combined signals of picture video and the second sound intermediate frequency are
output from Pin (47) and sent into the sound intermediate frequency circuit SIF unit to be
processed via N201 Pin (53) after being filtered and switched over by sound intermediate
frequency band-pass filter Z261 or Z262. The sound audio signals obtained are then sent into
the audio switch circuit of the TV/AV electronic switch circuit. After the electronic volume
N101 LA7910 Band Switch Truth Table
Input
3 4
L L
H L
L L
H H
Output
1 2
L L
L H
H L
L L
7 8
H L
L L
L L
L H
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