VII. IC function pins
1. Integrated circuits used in this model
1) TBA1238AN: picture intermediate amplification, sound intermediate amplification,
video signal processing, chrominance signal processing, RGB output circuit, horizontal
and field oscillating scan circuit.
2) TMP87CK38N: super central micro-processing unit.
3) LA7830 (LA7833): field scan circuit
4) LA4275: sound power amplifier circuit
5) LA7910: wave band change-over switch
2. IC functions and parameters
N402 LA7830 (LA7833)
Reference Resistance(K
Ω
)
No. Function Reference
Voltage(V)
Forward Backward
1 Grounding
0
0
0
2 Output
14
0.45
1.6
3
Pump power supply output
24(26)
0.5
∞
4
Field scanning sawtooth signal input
0.9
0.9
1
5 Field scanning sawtooth signal
forming terminal
0.8 0.65 1.4
6
Field power supply
24(26)
0.5
4.5
7
Field power supply input
1.9
0.72
30
N701 LA4275
Reference Resistance(K
Ω
)
Item Function Reference
Voltage(V)
Forward Backward
1 Grounding
0
0
0
2
Power amplifier output
10
0.55
4.5
3 Power
supply
20
0.42
2.8
4
Ripple wave filtering
10
1.2
2.4
5 Grounding
0
0
0
6 Audio
Input
0.7
1.1
∞
7 Feedback
0.2
0.72
2.0
N201 TB1238AN
Reference Voltage(V)
Reference Resistance(K
Ω
)
Pin Function
Without
signal
With
signal
Forward(
Ω
) Backward(
Ω
)
1 Unweighted
5.0
5.0
800
2000
2
Audio signal output
3.5
3.5
750
2000
3
PIF circuit power supply
9.0
9.0
460
600
4
AFT output and auto-adjusting
2.1
2.1
750
600
5
PIF circuit grounding
0
0
0
0
6
IF signal input pin
2.0
2.0
680
2000
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