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LCD TELEVISION
LC-37T18
America
CONTENTS
Safety precautions...................................................................................... 1
Alignment instructions ................................................................................ 3
Software upgrade method...............................................................................
8
Working principle analysis of the unit...............................................................9
Block diagram.............................................................................................10
IC block diagram.........................................................................................11
Wiring diagram ............................................................................................
21
Troubleshooting............................................................................................
22
Schematic diagram.................................................................................... 30
APPENDIX-A: Exploded View
Attention: This service manual is only for service personnel to take reference with. Before
servicing please read the following points carefully.
Safety precautions
1. Instructions
Be sure to switch off the power supply before replacing or welding any components or
inserting/plugging in connection wire Anti static measures to be taken (throughout the entire
production process!):
a) Do not touch here and there by hand at will;
b) Be sure to use anti static electric iron;
c) It's a must for the welder to wear anti static gloves.
Please refer to the detailed list before replacing components that have special safety requirements.
Do not change the specs and type at will.
2. Points for attention in servicing of LCD
2.1 Screens are different from one model to another and therefore not interchangeable. Be sure to
use the screen of the original model for replacement.
2.2 The operation voltage of LCD screen is 700-825V. Be sure to take proper measures in
protecting yourself and the machine when testing the system in the course of normal operation or
right after the power is switched off. Please do not touch the circuit or the metal part of the module
that is in operation mode. Relevant operation is possible only one minute after the power is
switched off.
2.3 Do not use any adapter that is not identical with the TV set. Otherwise it will cause fire or
damage to the set.
2.4 Never operate the set or do any installation work in bad environment such as wet bathroom,
laundry, kitchen, or nearby fire source, heating equipment and devices or exposure to sunlight etc.
Otherwise bad effect will result.
2.5 If any foreign substance such as water, liquid, metal slices or other matters happens to fall into
the module, be sure to cut the power off immediately and do not move anything on the module lest it
should cause fire or electric shock due to contact with the high voltage or short circuit.
2.6 Should there be smoke, abnormal smell or sound from the module, please shut the power off at
once. Likewise, if the screen is not working after the power is on or in the course of operation, the
power must be cut off immediately and no more operation is allowed under the same condition.
2.7 Do not pull out or plug in the connection wire when the module is in operation or just after the
power is off because in this case relatively high voltage still remains in the capacitor of the driving
circuit. Please wait at least one minute before the pulling out or plugging in the connection wire.
2.8 When operating or installing LCD please don't subject the LCD components to bending, twisting
or extrusion, collision lest mishap should result.
2.9 As most of the circuitry in LCD TV set is composed of CMOS integrated circuits, it's necessary
to pay attention to anti statics. Before servicing LCD TV make sure to take anti static measure and
ensure full grounding for all the parts that have to be grounded.
2.10 There are lots of connection wires between parts behind the LCD screen. When servicing or
moving the set please take care not to touch or scratch them. Once they are damaged the screen
1
would be unable to work and no way to get it repaired.
2.11 Special care must be taken in transporting or handling it. Exquisite shock vibration may lead to
breakage of screen glass or damage to driving circuit. Therefore it must be packed in a strong case
before the transportation or handling.
2.12 For the storage make sure to put it in a place where the environment can be controlled so as to
prevent the temperature and humidity from exceeding the limits as specified in the manual. For
prolonged storage, it is necessary to house it in an anti-moisture bag and put them altogether in one
place. The ambient conditions are tabulated as follows:
Temperature Scope for operation 0 ~ +50 oC
Scope for storage -20 ~ +60 oC
Humidity Scope for operation 20% ~ 85%
Scope for storage 10% ~ 90%
2.13 Display of a fixed picture for a long time may result in appearance of picture residue on the
screen, as commonly called "ghost shadow". The extent of the residual picture varies with the
maker of LCD screen. This phenomenon doesn't represent failure. This "ghost shadow" may remain
in the picture for a period of time (several minutes). But when operating it please avoid displaying
still picture in high brightness for a long time.
3. Points for attention during installation
3.1 The front panel of LCD screen is of glass. When installing it please make sure to put it in place.
3.2 For service or installation it's necessary to use specified screw lest it should damage the screen.
3.3 Be sure to take anti dust measures. Any foreign substance that happens to fall down between
the screen and the glass will affect the receiving and viewing effect
3.4 When dismantling or mounting the protective partition plate that is used for anti vibration and
insulation please take care to keep it in intactness so as to avoid hidden trouble.
3.5 Be sure to protect the cabinet from damage or scratch during service, dismantling or mounting.
2
Alignment instructions
1. Test equipment
Digital multimeter, signal generator (54200)
VG849 (HDMI signal generator)
CA210 (White balancer)
2. The alignment flow chart (see below Fig.1)
Write N105, N403, N607, N70, N606
To produce main board, TV board and other board
Check the TV board
Check accessories and then packing
Check the MAIN board
Input VGA signal source, check is the display is
normal in PC state and various function (analog
control) H-V center etc. The AV-out output sound
Check the buttons board and IR receive board is originally signal
Combined test for general assembly
Input HDMI and DVI signal source, check if
the HDCP KEY is normal. The AV-out output
sound is originally signal
Aging
Input YpbPr/YcbCr 1/2 signal source; check if the
picture and sound analog control is normal in the
ADC correction and white balance adjustment COMPONENT state. The AV-out output sound is
originally signal
Input the center signal source, check if various Input AV1/S/AV2 signal source, check if the
functions of TV (search channel, system identify various terminal functions (system identify and
and analog control etc.), earphone output, speaker analog control etc.) and the picture and sound of
output and the picture and sound of AV-out is AV-out is normal.
normal
Fig.1 Flow process of alignment
3. Alignment instructions
3.1 the main board adjustment
a. Connect the X602 of main board to the infrared receive board, the supply power plug to X1, then
3
the indicator of the infrared receive board is red light.
b. Press the POWER button; the indicator change to blue light, the LED1 of main board is flicker of
slow.
c. Write program to N102
d. Check if various channels are normal.
3.2 The TV board adjustment
a. Connect the high frequency board to main board, and connect the X501 and X502 to the supply
power.
b. Press the POWER button, the indicator change to blue light.
c. Check if the picture and sound of TV/AV1/AV2/S/YPBPR1/TPBPR2 and sound of HDMI/VGA
channels are normal. Check the STEREO and SAP. Check the picture and sound of the
TV/AV1/S/AV2.
3.3 the unit adjustment
After install the unit, check it is normal working.
3.4 Aging
a. Select the TV channel, the screen is noise wave of no signal TV
b. Aging an hour.
3.5 ADC correction and white balance adjustment (use white balancer CA210 and signal generator
VG849)
Enter the factory menu method: press "1" "9" "7" "9" button in the window menu state.
Note: warm color temperature coordinate (285, 294); warm color temperature coordinate (284, 299).
LC-42T17, LC-47T17 and LC37T25/T7 cool color temperature coordinate (270, 283).
3.5.1 HDMI channel
a. Input 8 level gray signal 720p/60Hz.
b. Brightness to 50, contrast to 50.
c. Color temperature to warm.
d. Enter color temperature setup menu.
e. Adjust RED GAIN, GREEN GAIN, BLUE GAIN, until the fifth level color coordinate (270, 283).
3.5.2 D-SUB channel
a. Input the 16 level gray signal 1027 x 768 @ 60(TIMING: 889, PATTERN: 921)
b. Brightness to 50, contrast to 50.
c. Enter the ADC auto correction
d. Color temperature to warm.
e. Enter the color temperature setup menu.
f. Input the 8 level gray signal 1027 x 768 @ 60(TIMING: 889, PATTERN: 920)
g. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate
(284, 299).
h. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,
299).
i. Repeat the g and h step, until the third and the seventh level color coordinate (284, 299).
j. Color temperature to cool.
k. Enter the color temperature setup menu.
l. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate
(270, 283).
m. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,
4
283).
n. Repeat the L and M step, until the third and the seventh level color coordinate (270, 283).
3.5.3 high definition channel
a. Input the 720P SMPTE COLOR BAR signal (TIMING: 976, PATTERN: 984).
b. Brightness to 50, contrast to 50.
c. Enter the ADC auto correction.
d. Color temperature to warm.
e. Enter the color temperature setup menu.
f. Input the 8 level gray signal 720b/60Hz(TIMING: 976, PATTERN: 920).
g. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color
coordinate (284, 299).
h. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,
299).
i. Repeat the g and h step, until the fourth and the seventh level color coordinate (284, 299).
j. Color temperature to cool.
k. Enter the color temperature setup menu.
l. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color
coordinate (270, 283).
m. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,
283).
n. Repeat the l and m step, until the fourth and the seventh level color coordinate (270, 283).
o. Holding the pattern signal, change the timing signal, repeat the G to the M step for 480i, 480p,
and 1080i signal.
3.5.4 the VIDEO channel
a. Input the eight level gray signal of PAL
b. Brightness to 50, contrast to 50.
c. Enter the factory menu.
d. Color temperature to warm.
e. Enter the color temperature setup menu.
f. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color
coordinate (284, 299).
g. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,
299).
h. Repeat the f and g step, until the fourth and the seventh level color coordinate (284, 299).
i. Color temperature to cool.
j. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color
coordinate (270, 283).
k. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,
283).
l. Repeat the j and k step, until the fourth and the seventh level color coordinate (270, 283).
3.5.5 the RF channel
a. Input the center signal source, set to D-8 channel
b. Brightness to 50, contrast to 50.
c. Enter the factory menu.
d. Color temperature to warm.
5
e. Enter the color temperature setup menu.
f. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate
(284, 299).
g. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,
299).
h. Repeat the f and g step, until the third and the seventh level color coordinate (284, 299).
i. Color temperature to cool.
j. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate
(270, 283).
k. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,
283).
l. Repeat the j and k step, until the third and the seventh level color coordinate (270, 283).
4 Performance check
4.1 TV terminal
Input the center signal source to RF terminal, enter searching menu auto search, check if the
leak channel, half-auto search channel, fine tune, earphone and speaker are normal. Check the AV
OUT.
4.2 AV1/S/AV2 input terminals
Input AV1/S/AV2 signal source, check the picture and sound.
4.3 VGA terminal
Input the VGA signal (K7253 signal generator), separate input VGA format signal of table 1, check
the picture and sound
Table1 PC display format signal
pixel clock pulse
No. Resolution H-frequency(kHz) V-frequency(Hz) remark
frequency(MHz)
1 720 x 400 31.47 70.08 25.17 DOS
2 640 x 480 31.50 60.00 25.18 DOS
3 640 x 480 37.90 72.00 31.50 Mac.(SOG)
4 640 x 480 37.50 75.00 31.50 VESA
5 640 x 480 43.30 85.00 36.00 VESA
6 800 x 600 35.16 56.25 36.00 VESA
7 800 x 600 37.90 60.00 40.00 VESA
8 800 x 600 46.90 75.00 49.50 VESA
9 800 x 600 48.08 72.19 50.00 VESA
10 832 x 624 49.00 74.00 57.27 Mac.(H+V)
11 1024 x 768 48.40 60.00 65.00 VESA
12 1024 x 768 56.50 70.00 75.00 VESA
13 1024 x 768 60.00 75.00 78.75 VESA
14 1280 x 1024 64.00 60 108.00 SXGA
15 1280 x 1024 80.00 75 135.00 SXGA
16 1600 x 1200 75.00 60 162.00 UXGA
4.4 YPbPr terminal
Input the YPbPr signal source (K7253 signal generator), separate input format signal in table of
6
table 2, check the picture and sound.
Table 2 Component format signal
No. H-frequency(kHz) V-frequency(Hz) signal
1 15.735 60 SDTV 480i
2 15.625 50 SDTV 576i
3 31.47 60 SDTV 483p
4 45.00 60 HDTV 720p
5 33.75 60 HDTV 1080i
6 28.13 50 HDTV 1080i
7 67.50 60 HDTV 1080p
8 56.25 50 HDTV 1080p
4.5 HDMI terminal
Input the DHMI signal source (VG849 signal generator), separate input format signal in table of
table 3, check the picture and sound.
Table 3 HDMI format signal
No. H-frequency(kHz) V-frequency(Hz) signal
1 15.735 60 SDTV 480i
2 15.625 50 SDTV 576i
3 31.47 60 SDTV 483p
4 45.00 60 HDTV 720p
5 33.75 60 HDTV 1080i
6 28.13 50 HDTV 1080i
HDMI format signal of audio
channel 2
sampling rate support 32Kbit/s 44.1Kbit/s 48Kbit/s
bit wide support 16bit,20bit,24bit
7
Method of software upgrading
Steps of software upgrading are as follows:
1. Select a serial connection wire and a VGA connection wire and then connect them by means of a
patch panel;
2. Use a serial wire to connect the PC to the patch panel and set TV set to off state;
Open the software upgrade file holder and double click FlashUpgrader.exe (window
2000/XP/NT)
The following interfaces will show up after running the program:
Based on the computer features, set up the serial port (COM Port). Select corresponding serial port
(if it's unable to FLASH WRITE, change to another port). Baud is selected to be 115200. Then
select Reset Target After Download. Click FLASH pushbutton, it's ready to run. For other settings,
please refer to the Fig. Above (already defaulted by the system, normally no need to change).
Switch on TV set the FLASH write program begins to run;
When the upgrading is complete, a window (below) will be opened. Press "Finish" button to
complete the process.
Note: Do not shut the power off or turn the TV set on during the FLASH write. Otherwise it
may lead to no way for flash to rewrite.
8
Working principle analysis of the unit
The unit has two MCU, the main MCU is PW218 (N601): it is used to control all the chips' working
status on the main board (including image processing, channel switch, sound processing, image
display etc.), sub CPU, OSD, searching channels, image effect adjustment, buttons control, infrared
remote control etc.; the sub CPU is ATMEGA8L (N606): it is used to control power supply, including
standby and turning on the unit by using remote control etc.. The two MCU correlates with each
other through pin 14 INT (interruption) of ATMEGA8L, pin 28 and 29 SDA, SCL.
Audio signal of the tuner will then be sent to AV switch box M52797 (N400), the audio signal of AV1,
AV2 and HD2 of the main board will also be sent to M52797 (N400) at the same time. The selected
audio signal after switching will be sent to R2S15900 (N301), and then switching selection will be
done towards the above audio signal together with the audio signal of VGA, HDMI and HD1. The
two chips are controlled by PW218 (N601), after the above process the finally selected way will be
set to X300 earphone socket after under the control of volume, treble and bass which is finished by
R2S15900 (N301), the earphone socket has the switching function, when earphone is plugged,
sound will be sent to earphone amplifier NJW1109 (N302), then sent back to earphone socket after
power amplification. If earphone is unplugged, sound will be sent to sound amplifier TPA3008 to do
amplification and then sent to speaker.
Image parts:
Video signal of AV1 and AV2 will also be sent to M52797 (N400) at the same time, two groups of
video output will be obtained after switching, one group of video output together with its audio output
will be sent to AV_OUT terminal to treat as AV OUT. The other group of video output together with
other video signals such as S-VIDEO, YpbPr1, YpbPr2 and VGA will be sent to PW2300 to do video
decoding or AD transformation, then output 24bit digital RGB signal and some corresponding
synchronous signals. Items such as 3D comb filter, channel switching, 5 lines Y/C separation and
color decoding etc. are primarily done by PW2300. 24bit digital RGB signal and some
corresponding synchronous signals outputted by PW2300 will then be sent to PW218 (N601). HDMI
signal will also be sent to AD9398 (N101) to de decoding and output 24bit digital RGB signal as well
as some corresponding synchronous signal, which will be sent to PW218 (N601). PW218 is a new
generation chip of Pixelworks, which has ability to deal with images, 24bit digital RGB signal and
some corresponding synchronous signals outputted by AD9398 and PW2300 will be sent to this
chip to deal with images. The chip has functions such as converting from interleaved into
line-by-line and image enhancement etc.. PW218 has SCALER function which can do format
conversion towards different input formats so as to meet the format needs of the screen and finally
output 24bit RGB signal. The interface standard of PDP screen is generally LVDS (low voltage
differential signal), so the digital RGB signal outputted from PW218 is needed to send to converting
interface chip N6 DS90C387 of LVDS to obtain LVDS signal, then it will be sent to the screen.
PW218 is also the main CPU, its programs are stored in periphery device flash N701, and software
upgrade through RS-232 interface is virtually upgrading the stored programs through PW218
towards N701.
Chief functions:
High definition 1080P LCD
16:9 wide screen; Support several kinds of HDTV wide voltage range, low standby power
consumption (less than 1W); One group of D-SUB, S-VSH (Y/C), RS232, AVOUT, HEADPHONE,
HDMI, two groups of YPbPr/YCbCr, AV.
9
Block diagram
I2C1
YPbPr1 Audio PC Audio HDMI Audio
RF Audio
AUDIO&SIF
Tuner TPA3008D2
MEGAL8
IR
RF Video
earphone
KEY
AV Out N400
NJW1109
M52797SP jack
YPbPr2 Audio
AV switch STV8216
AV2
AV Audio Out
AV1
Flash
YPbPr1
YPbPr2 V port
S Video PW2300
PW2300
PC DS90C387 Panel
PW218
RS232 MAX3232C
memory G port I2C2 EEPROM
HDMI AD9880 24LC32
AD9398
PCM1742
KEY I2S interface audio
D/A DDR 256M
E2PROM SDRAM
IC block diagram
1. AD9880 and AD9398
AD9880 have HDMI digital and analog terminal of working frequency 165Hz, it support 1080P
(non-interlaced scanning) and UXGA (1600 x 1200/60Hz) video format, also it support eight audio
channel of 192KHz. AD9398 without analog terminal.
Internal Block Diagram
11
PIN configuration
AD9880 (AD9398) PINS FUNCTIONS
Pin Name Function Pin Name Function
2-9 GGE(0-7) Converter output 44 RXC+ DVI input
12-19 GBE(0-7) Converter output 49 DDC_CLK HDCP Slave Serial Port
Data Clock
92-99 GRE(0-7) Converter output 50 DDC_DATA HDCP Slave Serial Port
Data I/O
20, 21 MCLK Control clock output 51 MCL HDCP Master Serial Port
Data Clock
22 I2S_SCK Audio serial clock output 52 MDA HDCP Master Serial Port
Data I/O
23 I2S_WS Bus clock data output 82 SCL-1 Serial Port Data Clock
12
27 I2S_SD Bus audio data output 83 SDA_1 Serial Port Data I/O
34 RX0- DVI input 84 G_FIEL0 Odd/Even Field Output
35 RX0+ DVI input 85 G_VS VSYNC Output Clock
37 RX1- DVI input 86 G_VHS Sync on Green Slicer
Output
38 RX1+ DVI input 87 G_HS HSYNC Output Clock
40 RX2- DVI input 88 G_DE Data Enable
41 RX2+ DVI input 89 G_CLK Data Output Clock
43 RXC- DVI input
2. PW2300
PW2300 is front processing signal of integration highly performance, multi-system, 3D video
decoder and three highly velocity AD converter chip. It supports HDTV, NTSC, PAL and SECAM. Its
analog port support 1080P(150MHz).
Internal Block Diagram
PW2300 PINS FUNCTION
Pin Name Function Pin Name Function
A4 XIN Resonator input P1 R_2 AV2 red input
A5 XOUT Resonator input P2 B_2 AV2 greed input
B2 SDA I2C bus data P3 SOG_2 AV2 greed sync input
13
B3 SCL I2Cbus clock P4 G_2 AV2 blue input
K2 VGA-R1 VGA(red) R1 CVBS_1 TV composite video signal input
K1 VGA-G1 VGA(greed) R2 Y_1 S-VHS brightness signal input
L1 VGA-SOG1 VGA(greed sync signal) R3 CVBS_SOG1 TV composite video signal greed sync
input
M1 VGA-B1 VGA(blue) R4 C_1 S-VHS chrominance signal input
T1 VGA_H VGA(H-sync signal) B9 GVBI Vertical blanking blank
T3 VGA_V VGA(V-sync signal) E16 G_VS V-SYNC output
N1 R_1 AV1 red input F14 G_HS H-SYNC output
N1 G_1 AV1 greed input F15 G_AHS H-SYNC of non-processing
N3 SOG_1 AV1 greed sync input G15 G_DLK Clock output
N4 B_1 AV1 blue input GBE(0-7) blue even pixel data output
GBO(2-9) Blue odd pixel data output GGE(0-7) greed even pixel data output
GGO(2-9) greed odd pixel data output GRE(0-7) red even pixel data output
GRO(2-9) red odd pixel data output
3. PW218
PWE218 is highly quality SOC picture processing chip, it contain Scaling and Deinterlacing
functions.
Internal Block Diagram
14
4. TPA3008
TPA3008 is double channel 10W stereo D class audio amplifier.
Internal Block Diagram
PINS FUNCTION
Pin Name Function Pin Name Function
1 SHUTDOWN Shut down control signal 17 LOUTN Negative audio output for left channel
3 RINP Positive audio input for right channel 20 LOUTP Positive audio output for left channel
4 V2P5 2.5V Reference for analog cells. 27 ROSC I/O current setting resistor for ramp
generator.
5 LINP Positive audio input for left channel 41 ROUTP Positive audio output for right channel
11 FAULT Volume control 44 ROUTN Negative audio output for right channel
5. DS90C387
The DS90C387/DS90CF388 transmitter/receiver pair is designed to support dual pixel data
transmission between Host and Flat Panel Display up to QXGA resolutions. The transmitter
converts 48 bits (Dual Pixel 24-bit color) of CMOS/TTL data into 8 LVDS (Low Voltage Differential
Signalling) data streams. Control signals (VSYNC, HSYNC, DE and two user-defined signals) are
15
sent during blanking intervals. At a maximum dual pixel rate of 112MHz, LVDS data line speed is
672Mbps, providing a total throughput of 5.38Gbps (672 Megabytes per second). Two other modes
are also supported. 24-bit color data (single pixel) can be clocked into the transmitter at a maximum
rate of 170MHz. In this mode, the transmitter provides single-to-dual pixel conversion, and the
output LVDS clock rate is 85MHz maximum. The third mode provides inter-operability with
FPD-Link devices.
Internal Block Diagram
Pin Description
No. Pin name Description No. Pin name Description
11 CLKIN Clock input 3-10 TTL Red data
54 HSYNC Horizontal sync 93-100, 1, 2 TTL Greed data
55 YSYNC Vertical sync 85-92 TTL Blue data
16
Pin Diagram
17
6. STV8216
Demodulator block diagram of STV8216 is follow:
Pin Description Pin Description
1 AV_LOUT 31 HPL
2 AV_ROUT 32 HPR
9 AUDIO_ALOUT 35 EINMUTE
10 AUDIO_AROUT 39 SCL
14 PC_L 40 SDA
15 PC_R 52 XTO
23 HDMI_L 53 XTI
24 HDMI_R 73 SIF
28 AMPRIN 78 AVDIO OUT
29 AMPLIN
18
7. M52797D
Internal Block Diagram
Pin description
Pin Name Description Pin Name Description
3 HD2_L Audio input 5 HD2_R Audio input
6 AV1_L Audio input 8 AV1_R Audio input
9 AV2_L Audio input 11 AV2_R Audio input
27 TV_L Audio input 25 TV_R Audio input
24 Left audio channel output 22 Right audio channel output
19
8.CM2006
Internal Block Diagram
Pin description
Pin Name Description Pin Name Description
1 VCC 3.3V 11 DDC_IN2 DDC _input2
3, 4, 5 VIDEO_1_2_3 Video input 12 DDC_OUT2 DDC output
6 GND GND 13 SYNC_IN1 Sync input1
7 Vcc-DDC 5V DDC 14 SYNC_OUT1 Sync output1
8 BYP Bypass capacitance 15 SYNC_IN2 sync intput2
9 DDC_OUT1 DDC output 16 SYNC_OUT2 Sync output2
10 DDC_IN1 DDC _output1
20
Wiring diagram
X604
782-LYT25-0100
X60112
CN2
RS-232C CNF1 J1
X8
X101
CN1
HDMI
LCD PANEL
X7
X401
VGA
KEYS BOARD
XA01
VGA AUDIO IN
X402
X3 (12) X4 X6 X5 X603 X602
REMOTE RECEIVER
SPEAKER
X500 X604 X602 X603
\ CN2 CN3 CN4 CN5
X608
YPBPR
X700
782-LYT25-5500
X6
YPBPR AUDION IN
X502
X605
S-VIDEO SUPPLY POWER
X501
X606
AV IN
X601
AV OUT
CN1
X300
HEADPHONE
AC220
22
Trouble shooting
1. Fault clearance
Before servicing please check to find the possible causes of the troubles according to the table
below.
1.1 Antenna (signal):
Picture is out of focus or jumping Bad status in signal receiving
Poor signal
Check if there are failures with the electrical connector or
the antenna.
Check if the antenna is properly connected.
Fringe in picture Check if the antenna is correctly oriented.
Maybe there is electric wave reflected from hilltop or
building.
Picture is interfered by stripe shaped Possibly due to interference from automobile, train, high
bright spots voltage transmission line, neon lamp etc.
Maybe there is interference between antenna and power
supply line. Please try to separate them in a longer
distance.
Maybe the shielded-layer of signal wire is not connected
properly to the connector.
There appear streaks or light color Check if interfered by other equipment and if interfered
on the screen possibly by the equipment like transmitting antenna,
non-professional radio station and cellular phone.
1.2 TV set:
Symptoms Possible cause
Unable to switch the power on Check to see if the power plug has been inserted properly
into the socket.
No picture and sound Check to see if the power supply of liquid crystal TV has
been switched on. (As can be indicated by the red LED at
the front of the TV set)
See if it's receiving the signal that is transmitted from other
source than the station
Check if it's connected to the wrong terminal or if the input
mode is correct.
Check if the signal cable connection between video
frequency source and the liquid crystal TV set is correct.
Deterioration of color phase or color Check if all the picture setups have been corrected.
tone
Screen position or size is not proper Check is the screen position and size is correctly set up.
Picture is twisted and deformed Check to see if the picture-frame ratio is properly set up.
Picture color changed or colorless Check the "Component" or "RGB" settings of the liquid
crystal TV set and make proper adjustment according to the
22
signal types.
Picture too bright and there is Check if the contrast setting is too high.
distortion in the brightest area Possibly the output quality of DVD broadcaster is set too
high.
It maybe also due to improper terminal connection of the
video frequency signal in a certain position of the system.
Picture is whitish or too bright in the Check if the setting for the brightness is too high
darkest area of the picture Possibly the brightness grade of DVD player (broadcaster)
is set too high.
No picture or signal produced from Check if the cable is disconnected.
the displayer if "XXX in search" Check if it's connected to the proper terminal or if the input
appears. mode is correct.
There appears an indication - Check if the TV set can receive input signal. The signal is
"outside the receivable scope) not correctly identified and VGA format is beyond the
specified scope.
Remote control cannot work Check if the batteries are installed in the reverse order.
properly Check if the battery is effective.
Check the distance or angle from the monitor.
Check if there is any obstruct between the remote control
and the TV set.
Check if the remote control signal- receiving window is
exposed to strong fluorescence.
No picture and sound, but only Check if the antenna cable is correctly connected, or if it
hash. has received the video signal correctly.
Blur picture Check if the antenna cable is correctly connected.
Of if it has received the right video signal.
No sound Check if the "mute" audio frequency setting is selected.
Check if the sound volume is set to minimum.
Make sure the earphone is not connected.
Check if the cable connection is loose.
When playing VHS picture search When being played or in pause VHS picture search tape
tape, there are lines at the top or sometimes can't provide stable picture, which may lead to
bottom of the picture. incorrect display of the liquid crystal TV, In this case please
press "auto" key on the remote control so as to enable the
liquid crystal TV set to recheck the signal and then to
display correct picture signal
23
2. Identification criteria for the bright spot and dark spot of the LCD screen
Quantity allowed Distance between two spots
Category Criteria
15" 20" 22" 30" 40" 15" 20" 22" 30" 40"
One single
5 2 5 2 3
spot
Bright Two
15mm
spot neighboring 2 1 2 1 1
spots
Total No. 5 2 5 2 3
15mm
One single
6 7 5 4 10
spot
Dark Two
10mm 5mm
spots neighboring 2 2 2 1 5
spots
Total No. 6 7 5 4 10
Total defected point 8 7 5 4 /
Notes:
1. Definition of defected point (bright spot, dark spot): It is identified as a defected point if its area
exceeds 1/2 of a single picture element (R, G, B).
2. Definition of bright spot: It is identified as a bright spot if it is bright in the state of dark field and its
bright size remains unchanged
3. Definition of dark spot: It is identified as a dark spot if it is dark in the state of white field and its
dark size remains unchanged
4. Definition of two neighboring points: Defects of a group of picture elements (RB, RG, GB).
24
3. Troubleshooting guide
3.1 No raster, no picture and no sound
Check if the indicator is light
Yes No
Check the supply Check 5V-STBY
power D3.3V
Abnormal Normal
Cut off between the power
board and signal processing,
Short circuit the pin 1 (STANDBY) Check N501 and
check the 5V-STB
of X604 to 5V, then check the N601
supply power.
Normal Abnormal
Normal Abnormal Power board
Cut off the the power
board and video board problem
U24 Pull out P2 check to main board, check
abnormal power it
Normal Abnormal
Check the Short circuit in Power board
supply power a power line problem
of N606 and
crystal.
Check the power of
N201, N601, N204
and N701, crystal and
bus.
Note: Power supply for PDP is provided with over current and over voltage protection functions.
If there is over current or over voltage, this protection will function and no output.
25
2.With sound but no picture:
With sound but no picture
Display LOGO?
Yes No
Check if no image for all
other channels
No Yes Check if the X3,
X4 is signal
Check if the white wave?
Check program
balance of the factory
menu is normal? Unfix X3 and X4, turn on the unit
display the white screen
Normal
Yes No
Abnormal
Check the N201 Reset the EEPROM
Normal Abnormal
and peripheral
circuit
Check input signal of N601 Normal Check the supply
and power supply power (+120) of
backlight board
Normal Abnormal
Abnormal
N601 Check N201 and the
damaged circuit of output part
The supply power
board damaged
26
3.With picture but no sound.
With picture but no sound
If there is output from X700 of
No sound power amplification board
Check if input signal in pin 2 of sound
power amplification Sound box damaged
Sound power amp. or other peripheral circuit Measure if the sound input of the
have problem. Check power supply, if present channel corresponding to
SHUTDOWN pin control is normal and if N400 is normal
output short circuited or other problems that
cause protection to work.
Yes No
R2S15900 or other peripheral Check different levels of
circuit have problem circuit following input audio
signal channel
4. AV no picture
Check if pin 7(AV1) and pin10 (AV2) has signal input
Yes No
There is problem from Av
Check if the pin1 of X4 has signal output
socket to N102 channel
No Yes
N400 or other peripheral Check the N201 and peripheral circuit
circuit have problem
no Yes
PW2300 or other peripheral PW218 or other peripheral
circuit have problem circuit have problem
27
5. High frequency board overhaul flow
5.1 with picture but no sound
Check if other channel is normal
Yes No
Check if the earphone is normal Check the connection cable
Yes Normal
Check if the connection Check if the sound channel
No
cable and power cable is Yes of N400 is normal
normal The speaker
Yes No
has problem
No
R2S15900 and peripheral Check the circuit of the all
circuit and earphone socket levels sound channel
Check the audio power have problem
amplifier and peripheral.
28
5.2 A certain channel without picture of TV/AV YPBPR
Check if the VGA and
HDMI has same problem
Yes No
Check the main board Check the connection cable
and signal source is normal
Yes Normal
YPBPR channel
Check if the X600 socket is Check if the supply power
normal (5v, 9v and 12v) is normal
No AV/TV/S channel No
Check the YPBPR input Check if the X600 socket is Check the supply
circuit normal power
No Yes
Check the main board
S terminal channel AV/TV channel
Check the all levels Check if the input pin
No
circuit of S terminal of N400 has signal
channel
Yes
Check the M52797
and peripheral circuit
29
APPENDIX-A: Exploded View
PART LIST OF EXPLODED VIEW
No. PART NO. DESCRIPTIONRE
1 808-20358-212 ACTIVE panel
2 Front cover
3 870-10289-00 power supply bracket
4 360-30042-00 Power switch
5 700-60255-100 LED column
6 870-30216-00 LED columnbracket
7 700-60255-100 LED column
8 Infrared receiving board assy
9 Screen
10 870-1A235-00 Board connecting bracket
11 870-1A238-00 Board connecting bar
12 870-1A231-00 Connecting bracket of screen
13 870-10249-00 Stand bracket
14 870-1A237-00 Board connecting bar
15 870-10298-00 screen connecting bracket
16 Power board assy
17 808-10893-AF0 Rear cabinet baffle
18 Main board assy
19 808-10896-00 AV baffle
20 808-1A898-00 AV baffle
21 808-10812-AF0 Power lead cover
22 808-10914-AF0 speaker connecting Cover
23 615-10612-00 Stand assy
24 615-20517-00 Bottom speaker assy
25 742-30088-110 Line clasp
26 808-10894-AF0 Rear cabinet baffle
27 808-1C897-AF0 AV baffle
28 808-10892-AF0 Rear cabinet baffle
29 808-10900-AF0 Decorate left-right
30 808-10895-AF0 AV baffle
31 Rear cabinet
32 870-3B203-AF0 ButtonCoverbracket
33 Button board assy
34 High frequency board assy
35 743-1E210-8A1 Button decorate piece
36 870-10241-00 Mounting holder
37 870-10242-00 Mounting connecting bracket
38 804-20442-00 Connecting bar of screen
39 870-1A234-00 Board connecting bracket
40 870-1A230-00 Connecting bracket of screen
41 870-10236-00 Board connecting bracket
603-L37T180-14
Ver.1.0