18
P13/SDA1 79
I
2
C-bus data line 1
3.52
10.7K
P14/SDA2 80
I
2
C-bus data line 2
3.85
9.5K
2. Analysis of common path circuits
High frequency television signals, received via an antenna (or transmitted through
a cable TV system) to the input terminal of the high frequency tuner UV101, are
processed for tuning and high frequency amplifying and mixing, then an analog IF
signal will go through the sound surface wave filter. Intermediate frequency signals will
be transmitted to (38) and (39) of IC201(R2J10165GF). The mixed signals of picture
video signals output from (34) of IC201.
3. Analysis of sound power amplifying circuits
Sound power amplifying circuits are composed of integrated circuits TFA9800J
and peripheral components. TFA9800J is an integrated electrical circuit . Information
introducing functions and testing data for TFA9800J maintenance is listed in Table 2.
Table 2
SYMBOL PIN
DESCRIPTION
Working
Voltage (V)
Ground
Resistance (
Ω
)
-INV1
1
Non-inverting input 1
2.17 27M
SGND
2
Signal ground
0 0
SVRR
3
Supply voltage ripple rejection output
7.68 14.6K
Out 1
4
Output 1
7.59 4.72K
PGND
5
Power ground
0 0
OUT2
6
Output 2
7.61 4.73K
Vp
7
Supply voltage
15.67 15K
M/SS
8
Mute/standby switch input
2.95 115K
-INV2
9
Non-inverting input 2
2.14 27M
4. 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 (11) of IC201 (R2J10165GF) to (7) of
vertical scan output IC IC401 (LA9302).
Information introducing functions and testing data for LA9302 maintenance is listed in
Table 3. if a cylindrical color card is installed then a fluke III digital multimeter is used.
Table 3
SYMBOL PIN DESCRIPTION
Working
Voltage (V)
Ground
Resistance (
Ω
)
INPUT 1
Inverting
input
2.95 10.5K
SUPPLY VOLTAGE
2
Supply voltage
31.6 33M
Flyback generator
3
Flyback generator
4.19 2.2M
GND
4
Ground or negative supply
0 0
Output 5
Output
17.57 10M
output stage supply
6
Output stage supply
33.05 18M
Input 7
Non-inverting
input
2.95 11.85K
Summary of Contents for DX-RCRT20-09
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