Circuit Explanation - Haier HTN19R12 Service Manual

12. Circuit Explanation

1. Principle integrated circuits
A1. HTN19R12 color TV set composed of the following sections
(1) Small signal processing: super monolithic integrated circuits N204(LA76814A).
and memory N901 (AT24C08).
(2) Sound power amplifying: integrated circuits N701 ( LA4525).
(3) Horizontal and Vertical scan output circuits: Vertical output integrated circuits
N402 (LA78040), Horizontal output transistor V411 (TT2140), Horizontal flying
back transformer T402 (JF0501-19810).
Switch power supply: switch transformer T501 (BCK-01-90II), power transistor
(4)
V503 (2SD4460).
A2. Main integrated circuits:
(1) LA76814A
(2) LA78040
(3) LA4525
A3. Electrical circuit analysis
1、Microprocessor and Small signal processing: super monolithic integrated circuits ：
LA76814A
LA76814A is super large integrated circuit decoder, containing intermediate image
amplifying, intermediate sound amplifying, horizontal and vertical scan, small
signal processing, color decoding, hi-pressure tracing and over-load protection,
2
I C bus control.
Information introducing functions and testing data for maintenance is listed in Table 1.
1. N701 LC863424B
PIN Leads Function
1 Auto adjust Enable Pin
2 Blank
3 IIC data
4 IIC clock
Microprocessor
Picture IF/sound IF/video processing/H and V
Scan/color decoding
Vertical output integrated circuits
Sound power amplifying integrated circuits
Voltage (V) PIN
5.1 19
20
4.6 21
4.5 22
Circuit Explanation
Leads Function
OSD red signal output
OSD greem signal output
OSD blue signal output
OSD blank signal output
Voltage (V)
0.09
0.09
0.09
0.01