Page 1
LCD COLOUR TV
SERVICE MANUAL
CHASSIS NO.:LS03W
Please read this manual carefully before service.
1
Page 2
Catalog
Chapter 1: Specifications and Composition......................................3
Chapter 2: Function Introduction of Main ICs...................................5
Chapter 3: Analysis of Signal process flowchart and key point
measure date......................................................................7
Chapter 4: Maintenance Procedure and Examples of Typical
troubleshooting...................................................................9
Chapter 5: Factory Setup...................................................................15
Appendix 1
Circuit Schematic Diagram............................................18
2
Page 3
Chapter 1: Specification and Composition
1. Main Feature
Region
Color
RF signal
Video or Y/C signal
Program presetting
Audio output（THD≤
Power source
Sound demodulator
VGA input
YPBPR input
HDMI input
OSD language
Auto Off without
Signal Reception
Energy saving system
Plug and Play
system
Sound
system
7%）
CCD
America
NTSC、PAL M、PAL N
M
PAL 、NTSC、SECAM
68 （AIR：2-69）
125 CABLE：1-125）
6W+6W
100V～240V
Yes
BTSC
Yes
Yes
Yes
English, French, etc.
15 minutes
Customer could adjust LCD screen backlight brightness manually to save
energy.
LCD TV could be used as computer screen, no need for the installation of
software, which is Plug and Play in real sense
2. Unit IC Compositions：
The LT32GR01U is made up of switch power, system control circuit, video processing
circuit, audio processing circuit, Power Amplifier circuit, AV input circuit, LCD screen
module. Block circuit diagram is shown as below:
3
Page 4
TUNER
AV1/AV2 LVDS
S-VIDEO
YPbPr1/YPbPr2
VGA
MST9U19
DECODER/
SC
LAER
PANEL
TV Audio
HDMI
POL4558
Audio switch
Audio1(for AV1/YPbPr1/S-VIDEO)
Audio2(AV2/YPbPr2)
Audio3(VGA)
HCF4052
POL4558
Sound effect
AMP
TPA300BD2
3. Introduction of PCB module
The LT32GR01U is made up of power board, Side TV board, remote control reception
board, key board, and mainboard. The table below is the introduction of the function of all printed
Board modules.
No Parts Description
1
Mainboard
Module
2
Remote reception
module
Mainboard module is the core of LCD TV signal processing. Under the
control of the system control circuit, It undertakes the task of converting the
external input signal into the unified digital signal that the LCD screen could
identify. Mainboard controls the whole machine through IIC bus, decode
VIDEO signal, controls the Video (brightness, contrast, chroma, hue,
definition etc), white balance adjusts, generates OSD, de-interlaces signal,
converts signal frequency, and finishes signal A/D and D/A conversion,
video enhancement, LVDS signal coding and output; it has Scart , S-Video,
AV , YPbPr, HDMI and PC interface, Tuner input, sound demodulation,
sound processing, sound power amplifier, and online update.
The remote reception board module is constituted by an indicator-light and
a remote reception. Customer could manipulate the LCD TV by using
remote controller very conveniently. By the color of the indicator light, the
operation mode of the LCD TV could be judged (red is standby, green is
power on).
Page 5
Built-in powe
r
3
board module
Convert the 100V～240V （50/60HZ）AC into DC, output have +24v, +12V,
+5V, and the +5V_STB in standby state.
Keyboard
4
module
LCD screen
5
module
6 TV board TV board is used for RF signal.
Keyboard module has 7 function keys (program +/-, volume +/-, AV/TV,
menu ,power), customer could use the key to operate the TV freely.
LCD screen has built-in inverter that convert DC into high voltage AC signal to
turn on the backlight CCFL (Cold Cathode Fluorescent Light); the LCD screen
process the video signal from signal board and reappear.
Chapter 2: Function Introduction of Main ICs
1. Main ICs and functional modules of the LT32GR01U
Mainboard
No. Item no. Model Main function
1 U10
2 U2 EONP40-50GCP Flash, Store the Control program.
3 U1 AT24LC32 EEPROM
4 U3 SI9435 MOS switch
5 U4 TPA3008D2 Audio amplifier
6 U5 CM1117ADJ-3.3 5V to 3.3V DC conversion
7 U6 BM1084ADJ-1.8 3.3V to 1.8V DC conversion
8 U7 BM1084ADJ-3.3 5V to 3.3V DC conversion
9 U11 CD4052B Audio switch
10 U12 PI5V330S Video switch
11 U13 FM24C02 EEPROM
MST9U19
Video decoder, Audio signal processor, image
processor, A/D and D/A conversion
12 U14 FM24C02 EEPROM
TV board
No. Item no. Model Main function
5
Page 6
1 U1 TSN6312-N Tuner output sound IF and video signal
2 U2.U3 78M05 12V to 5V DC conversion
Function introduction of ICs or functional modules of the LT32GR01U
1.Tuner (JS-6H2/121 or CDT-6GPL22-00)
Pin No. Definition of pin Function description
1 Ground Ground
2 Ground Ground
3 VCC +5V power
4 SCL IIC bus (clock)
5 SDA IIC bus (data)
6 AS Ground
7 NC No connection
8 NC No connection
9 Ground Ground
10 Ground Ground
11 SIF/Out Sound intermediate Frequency output
12 Video/Out CVBS signal output
13
VCC（+5V）
+5V power
14 Audio/Out Audio signal output
2. Image processing IC MST9U19
Main features:
●Integrated 6th Generation Motion and Edge Adaptive De-interlacing
● Integrated ADC
● PC auto tune
●Built-in 8-bit LVDS Transmitter
● 6th generation cubic-4 image scaling engine
● Advanced Chroma Processing and Dynamic Contrast Function
● Green color stretch, blue color stretch, skin color enhancement
●Integrated 6th Generation Motion Adaptive 3D Digital Comb Video Decoder with
Programmable Filter
●60Hz/100Hz interlaced scanning and 50Hz/75Hz progressive scanning
● frame rate conversion
● Advanced Film Mode Recovery-3:2/2:2 pull down
● Build-in A/D conversion function
● Teletext function
● Supports 16/32bits SDRAM memory interface
● Multi-screen display mode
● OSD and VBI/Closed caption and advanced OSD engine
6
Page 7
Chapter 3: Analysis of Signal process Flowchart and key
point measure date
This chapter mainly introduces the receipt and dispose of AV signal, the power supply
system and system control process of this TV.
1. Video signal flow
RF signal is demodulated by tuner, then the obtained video signal and signals inputted
from COMPONENT terminal, 2-way AV, S-VIDEO, 2-way YPBPR interface, VGA interface
and HDMI interface are all sent into video-processing IC MST9U19 for decoding. The
different format input signals are changed into uniform LVDS signals, and are sent to LCD
screen.
2. Sound process flow
RF signal is demodulated by tuner, and then the obtained SIF signal (SIF-2 signal) is
directly processed by MST9U19. The output audio signal of MST9U19 is sent into power
amplifier TPA3008D2.
Signals from HDTV terminal, AV terminal, YPBPR interface and PC Audio are also
sent into MST9U19 for demodulation and sound process. The output audio signal is sent
into power amplifier TPA3008D2,
3. Power supply system
There are 4 ways of voltage output in the power panel: +24V（6A）、+12V（2A）、+5V
（2A）and +5VS（1A）. +24V output is provided for LCD screen; +12V output is provided
for power amplifier TPA3008D2. +5V output is changed into 1.8V output and 3.3V output
by DC/DC to satisfy the needs ICs. +24V, +12V and +5V outputs will be cut off in standby
state. While +5VS output is the power supply of infrared receiver and EEPROM etc, and
will be cut off when the AC is turn off.
(1) The composition and distribution of the TV power supply
+12V power
supply
J4
Pin 10.11
+5V
power
supply
J4
Pin 3,4
7
12V AUDIO
+5V_LC
V_VIDEO
+5V_4052
U4 power amplifier
TPA3008D2
Pin14.15.22.23.33.38.39.46.47
AUDIO_MUTE circuit
U10 PI5V330
Pin16
U11 CD4502B
Pin16
Page 8
p
pp
y
U7 BM1084ADJ
+3.3V_LDO
U6 BM1084ADJ
+1.8V_LDO
VDDC—1.8V
U10 MST9U19
Pin77.98.107.142
.158.203
POWERDOWN_A
J4 PIN2
l
U1 A T24L C32 Pin8
ower su
+5Vstb LC
+5VSTB
Back light height control
IIC Bus data interface
IIC Bus clock interface
VDDP_3.3V
U10 MST9U19
Pin88.100.102.103.119.
140.151.159.172.186
CM11 17ADJ
+3.3VA_LDO
+3.3V_ADC
+3.3V_AU
U10 MST9U19 Pin 36
U10 MST9U19 Pin 60
U2
EONP40-50GCP
+3.3V_SIF
+3.3V_MEMPLL
+3.3V_HDMI
U10 MST9U19 Pin 53
U10 MST9U19 Pin 105
U10 MST9U19 Pin 6.12
+3.3V_MPLL
U10 MST9U19
Pin 157.208
8
Page 9
4. Position and definition of the main components and sockets on mainboard
Socket definition
Serial
number
1 J1 Keyboard and Remote
Position
number
Connecting object Function description
+5V,LED-GRN,LED-RED,MENU,SEL,UP,DOWN,
control receiving board
LEFT,RIGHT,POWER,REMOTR,GND
2 J4 Inverter GND,GND,INV-ADJ,INV-ON,+12V,+12V
3 J7 Power In POWERDOWN-AC,+5VSTB-IN,+5V,+5V,VCC-PAN
NEL,VCC-PANNEL,GND,GND,GND,+12V,+12V
4 J5 Speaker R+,R-
5 J6 Speaker L+,L-
6 J11 TUNER SCL.SDA,TV-AFT,GND,IF,GND,CVBS,GND,AF,
GND,+5V,+5V,GND,12V
7 J9 LVDS VCC,VCC,VCC,VCC,VCC,GND,GND,GND,GND,G
ND,LVB0-, LVB0+, LVB1-, LVB1+, LVB2-, LVB2+,
LVBCK-, LVBCK+, LVB3-, LVB3+, LVA0-, LVA0+,
LVA1-, LVA1+, LVA2-, LVA2+, LVACK-, LVACK+,
LVA3-, LVA3+
Chapter 4: Maintenance Procedure and Examples of Typical
troubleshooting
Power troubleshooting
check Power Module
the input of AC is right or not
Y N
OK
N
Detect and repair the Electricity
Networks
the pin 2 of J7 is 5V or not?
Y
the pin3/4 of J7 is 5V or not
the pin10/11 of J7 is 12V or not
check 3.3V output of U5
1.8V output of U6, 3.3Voutput of
U7
N
LDO is broken or the
load is short circuit
Y
OK
9
Page 10
Display troubleshooting
1.
Blank Screen or the image showed
abnormal (backlight is light)
Panel Interface cable connect well
and ecactly
Y N
LCD is right or
not?
N Y
check the output networks,
circuit between U10 and J8
J8 and
change
the LCD
Y
Check power and Clock circuit
of U10
N
repair this
circuit
change
Panel Interface cable
10
Page 11
2.
White Screen
Panel power voltage is right
N Y
Check the Pin 5/6 of J7
(5V or 12V)
Y
Change U3
3.
Pin4 of U3 is low voltage?
Check the circuit between this pin and
U3 or I/O of U10 is broken (pin 112).
N
Check J7and the related circuit
N Y
Blank Screen
Pin4 of J4 is 5V
Check the output of U10
Y
LCD or Panel Interface
cable is broken
N
U10 is broken or
power supply
irregular
N
Chenk the 24V of Power Module
N Y
check Power Module
Y
Inverter is broken or the cable
connect not well
Check the control circuit,
netwoork of Q2 and pin 110 of U10
11
Page 12
Audio troubleshooting
p
1. check audio input
N
2. check power supply of power amplifier
N
NO SOUND
Y
the set up of Volume and mute are right
Y
The output signal of J5 and J6 is existed
1.Check the
audio
peripheral
equipment
2.check the
power circuit
of power
am
lifier
Rein-
stall
Y
Check
The
Speaker
Y
Check the circuit of
power amplifier
Check the input signal of pin2,6 of U4
Check pin 54.55.66-69 of U10
Whether exist the input
Y
Check the output signal of
U10(pin 74.75)
U10 is broken or power
supply is not good
N
N
N
Check the
Input equipment
12
Page 13
TV troubleshooting
r
1.
TV do not tune/ there is no picture
N
Check the pin12 of tuner whether it has signal
Y
Check
pin49 of
U10 and
filter
network
Check the
RF
peripheral
equipment
The input of RF is normal
Check the I2C of tuner (PIN4.5)
Y
N
Tuner is
broken .change
the tune
Y
check pin 3.13 of tuner whether is 5V
Y N
N
Check I2C network
(connect with pin
131.132
of U10)
Check the
power
supply of
this pin
2.
13
Page 14
TV has the picture but no picture
There has sound in PC/AV mode
N
Refer the audio
troubleshooting
process
Y
PC troubleshooting
Check the pin11 of the tuner whether it has signal output
Y N
Check the connection between
Mainboard and TV board.
IN PC MODE
Y
The tuner
Is broken.
The picture Is not
in the middle
Auto adjust
color is
abnormal
Check the R G B input of U10 is right
Y N
The setup is not
correct.
Check the
R G B
circuit
Reset.
Setup of osd is not
matching or do not
support the input
The image jitter
Check the HS and VS
is regular and steady
Y N
Check the
circuit
VS,HS
On signal
Check the
VS,HS
circuit
YP/CbP/Cr、S- Video、AV troubleshooting
14
Page 15
YP/CbP/Cr、S- Video、AV下
YP/CbP/Cr
No signal
color is abnormal
Check the Y, P/Cb, P/Cr input of U10 is right
All no signal
Y N
Check
U10
The setup is not
correct.
Reset.
Check the Y, P/Cb, P/Cr
Input network
Check the power of
U10 and Crystal
Oscillator X1.
Chapter 5: Factory Setup
Enter factory menu
Switch to TV Cable mode, and make LCD at operating state:
Press 【MUTE】 key on remote control；
Press number key “9”、“1”、“9” on remote control to enter password.
The detailed setting items are given bellow:
INDEX
0. Version
1.Picture Nonlinear
2. Picture Mode
3.Sound Nonlinear
4. Sound Mode
5. Offset Gain
6.Picture Adjustment
7. 9Win
15
Setting method
Press “” key
to enter submenu
Page 16
8. Function
9. Factory setting
A. Hotel Setting
submenu of each item
Use “”、“”keys on remote control to make up or down option and use“”、“”
keys to set.
1.Picture Nonlinear
Item Setting value
Port
V．Contrast 0-63-128-191-255
V．Brightness 0-63-130-191-255
V．Saturation 0-63-128-191-255
V．Sharpness 0-4-8-12-16
2. Picture Mode
Item Setting value
Brightness 50 45 55 50
Contrast 50 45 55 50
Hue 50 50 50 50
Saturation 50 35 65 50
Sharpness 50 40 50 50
Picture Mode
Normal Soft Vivid User
3. Sound Nonlinear
Item Setting value
Bass 0-6-12-18-24
Treble 0-6-12-18-24
4. Sound Mode
Item Setting value
Bass 50 40 60 50
Treble 50 40 60 50
Sound Mode
Normal News Movie User
5. Offset Gain
Setting value
Item
R G B
Offset
Gain
Auto Color
Video Col Tem. Normal Cool Warm User
Video R 50 50 55 50
Video G 50 50 50 50
Video B 50 55 50 50
PC Col Tem. Normal Cool Warm User
16
127 127 127
127 127 127
Page 17
PC R 50 50 55 50
A
t
i
PC G 50 50 50 50
PC B 50 55 50 50
6. Picture Adjustment
Item Setting value
Port Display the input mode
Mode Type Color, sound system, or input format
Picture
H.SIZE
Picture
TV AV1 AV2 S-VIDEO YPBPR1 YPBPR2 PC HDMI
42 42 42 20 21
26 24 23 18 17
V.SIZE
Picture
0 0 0 0 1
H.Pos H
Picture
135 134 112 109 23
H.POS L
Picture
0 0 0 0 0
V.POS.H
Picture
7 7 3 22
V.POS.L
8. Function
Item Setting value
First Language English
TTX Language WEST
Sound SYS M/N
Color SYS
DNR
NTSC
MID
9. Factory Setting
Item Setting value
Disable all
Power OFF
Buring Mode OFF
10.Hotel Setting
Item Setting value
Hotel Mode OFF
Volume Control OFF
Tune Control OFF
Max Volume
100
ccording
o various
format,
the value
s not
fixed
36
17
Page 18
Appendix 1
Circuit Schematic Diagram(see next page)
18
Page 19
19
Page 20
20
Page 21
21
Loading...