akira CT-21XF9, Service Manual

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39
Model No: CT-21XF9A
Version 1.0
8. Introduction for ic TDA7449
The TDA7449 is a volume tone (bass and treble) balance (left/right) processor for quality audio
application in TV system. Control of all the functions is accomplished by serial bus.
The pin functions and repair data of TDA7449 is listed in the table 10.
The inner structure block diagram of TDA7449 is show as figure 8.
Table 10 Pin functions and repair data of TDA7449
Digital multimeter (GDM8145)
Resistance for GND
(R x 200KÙ)
Pin Symbol
Quiescent
state (V) Dynamic
state (V)
Red pen
measure
Black
pen
measure
1 Cref 0.06 0.01 27.72 22.18
2 Vs 0.05 0.01 0.75 0.74
3 GND 0.07 0.01 0.00 0.00
4 Rout 0.07 0.01 31.37 22.48
5 Lout 0.09 0.01 31.39 22.43
6 R2 0.10 0.02 28.20 25.42
7 R1 1.24 0.23 28.07 26.30
8 L1 1.14 0.21 28.11 26.22
9 L2 0.09 0.01 28.22 27.15
10 L-M 0.10 0.01 24.41 22.62
11 R-M 0.11 0.01 24.44 22.53
12 B-Rin 0.07 0.01 27.74 27.02
13 B-Rout 0.07 0.01 27.67 21.42
14 B-Lout 0.06 0.01 27.66 21.33
15 B-Lin 0.07 0.01 27.76 27.04
16 T-L 0.06 0.01 29.94 28.25
17 T-R 0.06 0.01 29.97 28.23
18 GND 0.06 0.01 0.00 0.00
19 SCL 2.20 2.20 27.98 16.90
20 SDA 2.06 2.24 27.36 16.18