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SERVICE MANUAL
3Y31 CHASSIS
Design and specifications are subject to change without prior notice.
( ONLY REFERRENCE)
ENGINEER BY: CHECKED BY: PPROVED BY:
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Contents
Safety Notice
Technical specification-------------------------------------------Chassis Block Diagram--------------------------------------------5
IC Block Diagram -------------------------------------------------6-9
Transistor mark ----------------------------------------------------10
PCB Top/Bottom layer -------------------------------------------11-13
Service Adjustments ------------------------------------------- 14-17
Purity and Convergence Adjustment ----------------------------18
Control Location ---------------------------------------------------19
Input and Output Terminals----------------------------------------20
Operation Instructions
Mechanical Disassemblies----------------------------------------27
Circuit Diagram-----------------------------------------------------28
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3-4
------------------------------------------21-26
Safety Notice
SAFETY PRECAUTIONS
1:An isolation transformer should be connected in the power line between the receiver and
the AC line when a service is performed on the primary of the converter transformer of the
set.
2:Comply with all caution and safety-related notes provided on the cabinet back, inside the
cabinet, on the chassis or the picture tube.
3:When replacing a chassis in the cabinet, always be certain that all the protective devices
are installed properly,such as,control knobs, adjustment covers or shields, barriers,isola tion resistor-capacitor networks etc.. Before returning any television to the customer,the
service technician must be sure that it is completely safe to operate without danger of
electrical shock.
X-RADIATION PRECAUTION
The primary source of X-RADIATION in television receiver is the picture tube. The picture
tube is specially constructed to limit X-RADIATION emissions. For continued X-RADIATION
protection, the replacement tube must be the same type as the original including suffix
letter. Excessive high voltage may produce potentially hazardous X-RADIATION. To avoid
such hazards, the high voltage must be maintained within specified limit. Refer to this
service manual, high voltage adjustment for specific high voltage limit. If high voltage exceeds specfied limits, take necessary corrective action. Carefully follow the instructions for
+B1 volt power supply adjustment, and high voltage check to maintain the high voltage
within the specified limits.
PRODUCT SAFETY NOTICE
Product safety should be considered when a component replacement is made in any area
of a receiver. Components indicated by mark in the parts list and the schematic diagram
designate components in which safety can be of special significance. It is particularly
recommended that only parts designated on the parts list in this manual be used for component replacement designated by mark . No deviations fromresistance wattage or voltage ratings may be made for replacement items designated by mark .
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FEATURES:
l AC 90V - 260V 50/60Hz
l MULTI SYSTEM: PAL BG/DK/I,SECAM BG/DK(OPTION),NTSC M(OPTION)
l VOLTAGE SYNTHESISED TUNING SYSTEM
l 100/256 PROGRAM S MEM ORY (OPTION)
l BLUE BACK FUNCTION
l 120 MINUTES SLEEP TIMER
l FULL AUTO PROGRAM
l TIME ON
l CLOCK ; CHILD LOCK
l 2 AV INPUT
l GAME (OPTION)
l 8 PAGES TELETEXT (OPTION)
l BLACK LEVEL STRETCH
l PROGRAM VIEW FUNCTION
l FOUR PICTURE MODE：MILD;COLORTUL; STANDARD ;CUSTOM;DYNAMIC
GENERAL SPECIFICATION:
1、POWER CONSUMPTION： 14 ″ 70W （MAX.）
21 ″ ９０ W （ MAX.）
2、RECEIVE SYSTEM： D/K ; I ; B/G ; M
3、 COLOUR SYSTEM : PA L / SECAM / NTSC
4、VISION INTERMEDIATE FREQUENCY ： 38.9MHz
5 、 INTER-CARRIER FREQUENCY: 4.5 MHz (M)
5.5 MHz (B/G)
6.0 MHz (I)
6.5 MHz (D/K)
6. CHROMA IF FREQUENCY PAL/NTSC: 34.47/35.32 MHz
7、ANTENNA TYPE: DIN TYPE 75 OHM
8、 CHANNELS RECEIVING : VHF-1 A0;E2-E4;S1-S9 CH 46.25-161.25MHz
VHF-3 S10-S41; E5-E12 CH 168.25-463.25MHz
UHF E21-E69 CH 471.25-855.25MHz
9、 TUNING SYSTEM： VS TUNING
10、 AV IN/OUT： 2 AV I N + 1 AV STEREO OUT
11、AV IN/OUT SPECIFICATION： VIDEO IN----1.0 ±0.2V
P-P
75 OHM
AUDIO IN----0 -2V (r.m.s)
VIDEO OUT----1.0±0.2 V
P-P
75 OHM
AUDIO OUT----0-2V (r.m.s)
12、OSD LANGUAGE： ENGLISH
13、 AUDIO OUTPUT POWER: > 3W (1KHz, 0.5V INPUT , 10%THD)
14、SAFETY AUTHENTICATION STANDARD： CB
15、LED INDICATORS： POWER ON
16、 HAND SET TYPE ： HS08
17、HAND SET POWER SUPLY ： BATTERY 3V （UM-3/R6/AA）x2
18、COLOUR PICTURE TUBE： 14"－21" 90 DEGR EE TUBE
19、 REMOTE CONTROL DISTANCE: ≥5 m
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Chassis Block Diagram
9V (RGBout,CRT)
42V HORIZONTAL DRIVE
26V (VERTICAL)
IC401(Video)/
IC402(Audio)
SCART (in/out)
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IC Block Diagram
IC 201 (IIC BUS SINGLE CHIP VIF,SIF,VIDEO CHROMA) LA76818A/HA
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IC Block Diagram
IC 501&IC 502(3W AUDIO OUTPUT)LA 4285
1 2 6543 1097 8
INT
PRE
GND
EXT
IC801<TELETEXT> STV-5348
STTV/LFB
555
INT/EXT
SM
MA/SL
FFB
EVR
5V
EVR
CONT
POL
L23
46 2 444
18
++6++
D.C.
PWR
NF
VDDD
22
+
-
VCC
++
+
++++
+
PWR
GND
RL 8
VDDA
3
CVBS
CBLK
VCR/TV
XTI
XTO
VSSO
SCL
SDA
1
28
28
21
24
23
25
16
17
STV5348
CLAMPING
SYNCHRONIZING
DATA EXTRACTION
OSCILLATOR
FREQUENCY
SYNTHETIZER
TIME BASE
2
I C BUS
INTERFACE
7
VSSD
VSSA
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2726
TEST
Data
Clock
DATA DECODING
DATA
PROCESSING
Data
Address
8 PAGES
MEMORY
CTRL
Data
Address
DISPLAY
INTERFACE
RGB REF
ODD/EVEN
19
DV
TEST
20
CTRL
BLAN
12
13
COR
RED
8
GREEN
9
BLUE
10
Y
15
1411
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IC Block Diagram
IC301<Vertical Output> L A78040
IC601<POWER > ICE-1QS01
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IC Block Diagram
IC202<SECAM> L A7642
IC604,IC605,&IC606<REGULATORS> L7800 SERIES
REFERENCE
INPUT
1
VOLTAGE
STARTING
CIRCUIT
CURRENT
GENERATOR
REFERENCE
VOLTAGE
ERROR
AMPLIFIER
SOA
PROTECTION
THERRMAL
PROTECTION
IC602<PHOTO TRANSISTOR> TLP621
TLP621
1
2
1:ANODE
2:CATHODE
3:EMITTER
4:COLLECTOT
4
3
SERIES
PASS
ELEMENT
OUTPUT
GND
2
3
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Transistor Mark
E
PNP
A9
6
6
C
NPN
C2
4
82
B
E
B
C
PNP
E
C
2
1
2
0
B
C
PNP
A
101
5
E
C
B
NPN
E
C
C
1
8
1
5
B
NPN
B
C
2
7
1
7
E
C
D2499
B
L7809
INPUT
OUTPUT
INPUT
GND
E
C
L7812
GND
OUTPUT
INPUT
L7805
OUTPUT
GND
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