Circuit Explanation - Haier HT-2180 Service Manual

12.

Circuit Explanation

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
No.
1 Grounding
2 Output
3 Pump power supply output
4 Field scanning sawtooth signal input
5 Field scanning
forming terminal
6 Field power supply
7 Field power supply input
Item
1 Grounding
2 Power amplifier output
3 Power supply
4 Ripple wave filtering
5 Grounding
6 Audio Input
7 Feedback
Function
sawtooth signal
N701
Function
LA7830 (LA7833)
Reference
Reference Resistance(KΩ )
Voltage(V)
Forward
0 0
14 0.45
24(26) 0.5
0.9 0.9
0.8 0.65
24(26) 0.5
1.9 0.72
LA4275
Reference
Reference Resistance(KΩ )
Voltage(V)
Forward
0 0
10 0.55
20 0.42
10 1.2
0 0
0.7 1.1
0.2 0.72
26
Circuit Explanation
Backward
0
1.6
∞
1
1.4
4.5
30
Backward
0
4.5
2.8
2.4
0
∞
2.0