Haier 21FA18-T Service Manual page 23

the sound surface wave filters Z101 of this appliance according to system properties.
Intermediate frequency signals will be transmitted to (41) and (42) of N201(HAIER8873).
The mixed signals of picture video signals and secondary sound intermediate frequency
signals output from (31) of N201, After sound carrier frequency is trapped by the trap filter,
intermediate frequency signals are amplified and PLL image decoded, The AGC time
constant is dependent on C233 (2.2u) connected to (39) of N201 (HAIER8873),.
2.Analysis of sound power amplifying circuits
Sound power amplifying circuits are composed of integrated circuits AN7522N and
peripheral components. AN7522N is an integrated electrical circuit . Information
introducing functions and testing data for AN7522N maintenance is listed in Table 4. T if a
cylindrical color card is installed then a fluke III digital multimeter is used.
No.
1
2
3
4
5
6
7
8
9
7
8
9
3.Analysis of vertical sync and vertical scan output circuits
The field sync signals segregated from compound sync signals are used to activate the
vertical frequency segregation system which commences when a set amount of vertical
sync pulse signals are tested. Of the sync pulse frequencies obtained from segregation,
some are transmitted to the vertical tooth wave generator. The vertical frequency tooth
wave, after geometric processing, is transmitted from (16) of N204 (HAIER8873) to (5) of
vertical scan output IC N401 (STV9302A). The external resistor R443 (5.6KΩ) of N201 (16)
provides a reference current to the vertical tooth wave generator. The external capacitor
C244 (0.1uF) of pin (2) forms the vertical ramp wave. The vertical ramp wave is sending
the pin (4) of the vertical scan output integrated circuit N401 that is a complete bridge
current drive output circuit. After shaped and amplified the vertical ramp wave is output
from pin (2) of N401.
Information introducing functions and testing data for STV9302A maintenance is listed in
Table 4. if a cylindrical color card is installed then a fluke III digital multimeter is used.
Table 5
No.
Function
VCC
OUT1+
GND
OUT1-
STANDBY
IN1
GND
IN2
VOLUME
GND
IN2
VOLUME
Function
Grounding Resistance (R)
Working
Positive
Voltage (V)
(Ω)
12.56
6.52
0
6.52
3.75
1.43
0
1.43
1.99
0
1.43
1.99
Working Grounding Resistance (R)
Voltage
Positive
(V)
(Ω)
21
Negative (Ω)
Negative
(Ω)