LCD TELEVISION
LC-37T25
CONTENTS
Safety Precautions………………………………………………………………………..…
Alignment instructions. ………………………………….…………………………….…
Software upgrade method…………………………………………….……………………
Working principle analysis of the unit……………………..……………………….……
Block diagram………………………………………………………………………………
IC block diagram……………………………………………………………..…………….
Wiring diagram……………………………………………………………………………..…
Troubleshooting………………………………………………………..…………….…….
Schematic diagram…………………………………………………………………………..
APPENDIX-A: Assembly list
APPENDIX-B: Exploded view
1
3
8
9
11
12
24
25
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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 (LC-37T25& LC-42T17&LC-47T17)
d
f
p
g
t
n
d
r
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
ormal in PC state and various function (analog
control) H-V center etc. The AV-out output soun
Check the buttons board and IR receive board
is originally signal
Combined test for general assembly
Aging
ADC correction and white balance adjustment
Input the center signal source, check if various
functions of TV (search channel, system identify
and analog control etc.), earphone output, speake
output and the picture and sound of AV-out is
Input HDMI and DVI signal source, check if
the HDCP KEY is normal. The AV-out outpu
sound is originally signal
Input YpbPr/YcbCr 1/2 signal source; check if the
icture and sound analog control is normal in the
COMPONENT state. The AV-out output sound is
ori
inally signal
Input AV1/S/AV2 signal source, check if the
various terminal functions (system identify an
analog control etc.) and the picture and sound o
AV-out is 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.
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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
No. Resolution H-frequency(kHz) V-frequency(Hz)
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
pixel clock pulse
frequency(MHz)
4.4 YPbPr terminal
Input the YPbPr signal source (K7253 signal generator), separate input format signal in table of
remark
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.
The unit has one integrative tuner (including HF and IF amp. circuits). The signal received by
antenna is sent to tuner, under the control of MCU PW218 (N601) SDA and SCL, proper channel
selection and right system switching will be done by the tuner, then video signal and audio signal
will be output by the tuner through decoding and by high and intermediate amplification. Video
signal of the tuner will then be sent to Decoder PW2300 (N201). 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 the tuner will be sent to AV switch box M52797 (N400), 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.
9
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.
10
Block diagram
RF Audio
RF V ideo
YPbPr1
YPbPr2
EEPROM
LA72700V
STERO/SAP decoder
Audio and video
MAX3232C
KEY
N400
M52797SP
switch
AD9880
AD9398
Or
SRS processor
M62494
PW2300
PW2300
memory
PCM1742
I2S D/A
PC Audio HDMI Audio
R2S15900
TPA3008D2
NJW1109
AV Audio Out
V port
G port
Flash
PW218
DDR 256M
SDRAM
I2C1
Earphone
socket of
with switch
I2C2
MEGAL8
DS90C387 LCD panel
EEPROM
24LC32
IR
KEY
11
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
12
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
13
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
14
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
15
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
16
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
17
Pin Diagram
6. M62494 (SRS 3D Stereo + SRS 3D Mono processor)
M62494 has SRS 3D STEREO and SRS 3D MONO. There are three modes, those are SRS 3D
stereo SRS 3D mono and bypass. Each mode can be set by terminals.
Pin Description
Pin Name Description Pin Name Description
1 Rin1 Right channel of audio input 9 VCC Power
2 Lin1 Left channel of audio input 10 MUTE Mute
5 Rout Right channel of audio output 11 SRS STEREO ON OFF SRS stereo switch
8 Lout Left channel of audio output 12 SRS MONO ON OFF SRS MONO switch
18
Internal Block Diagram
19
7. L72700
Internal Block Diagram
Pin description
Pin Name Description Pin Name Description
5 PISIF IF of Sound
25 R OUT Right channel of audio output
input
11 SDA I2C bus 26 LOUT Left channel of audio output
12 SCL I2C clock 31 VCC 9V supply power
20
8. R2SI5900SP
Internal Block Diagram
21
PIN description
2, 27 right/left channel of audio
3, 26 HDMI(right/left channel of audio)
4, 25 VGA(right/left channel of audio)
5, 24 YpbPr1(right/left channel of audio)
11, 19 output the power amplifier(right/left channel of audio)
9. M52797D
Internal Block Diagram
22
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
10.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
23
Wiring diagram
X8
X601
X300
782-LYT25-0100
12
RS-232C
HDMI
VGA
VGA AUDIO IN
X3 (12) X4 X6 X5
X500 X604 X602 X603
YPBPR
KEYS BOARD
X603
X602
782-LYT25-5500
YPBPR AUDION IN
CN2 CN3
\
CNF1 J1
LCD PANEL
REMOTE RECEIVER
SPEAKER
CN4 CN5
S-VIDEO
AV I N
TUNER
AV OUT
HEADPHONE
SUPPLY POWER
CN1
24
AC220
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
bright spots
There appear streaks or light color
on the screen
1.2 TV set:
Symptoms Possible cause
Unable to switch the power on Check to see if the power plug has been inserted properly
No picture and sound Check to see if the power supply of liquid crystal TV has
Deterioration of color phase or color
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
Possibly due to interference from automobile, train, high
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.
Check if interfered by other equipment and if interfered
possibly by the equipment like transmitting antenna,
non-professional radio station and cellular phone.
into the socket.
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.
Check if all the picture setups have been corrected.
crystal TV set and make proper adjustment according to the
25
signal types.
Picture too bright and there is
distortion in the brightest area
Check if the contrast setting is too high.
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
darkest area of the picture
Check if the setting for the brightness is too high
Possibly the brightness grade of DVD player (broadcaster)
is set too high.
No picture or signal produced from
the displayer if “XXX in search”
appears.
There appears an indication -
“outside the receivable scope)
Check if the cable is disconnected.
Check if it’s connected to the proper terminal or if the input
mode is correct.
Check if the TV set can receive input signal. The signal is
not correctly identified and VGA format is beyond the
specified scope.
Remote control cannot work
properly
Check if the batteries are installed in the reverse order.
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
hash.
Check if the antenna cable is correctly connected, or if it
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
tape, there are lines at the top or
bottom of the picture.
When being played or in pause VHS picture search tape
sometimes can’t provide stable picture, which may lead to
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
26
2. Identification criteria for the bright spot and dark spot of the LCD screen
Category Criteria
One single
spot
Bright
spot
Dark
spots
Total defected point ≤8 ≤7 ≤5 ≤4 /
Two
neighboring
spots
Tot a l N o . ≤5 ≤2 ≤5 ≤2 ≤3
One single
spot
Two
neighboring
spots
Tot a l N o . ≤6 ≤7 ≤5 ≤4 ≤10
15" 20" 22" 30" 40" 15" 20" 22" 30" 40"
≤5 ≤2 ≤5 ≤2 ≤3
≤2 ≤1 ≤2 ≤1 ≤1
≤6 ≤7 ≤5 ≤4 ≤10
≤2 ≤2 ≤2 ≤1 ≤5
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).
Quantity allowed Distance between two spots
≥15mm
≥15mm
≥10mm ≥5mm
27
3. Troubleshooting guide
b
b
k
p
y
p
k
p
N
n
p
A
A
A
N
r
d
A
f
N
d
b
3.1 No raster, no picture and no sound
Check if the indicator is light
Check the suppl
ower D3.3V
bnormal
Short circuit the pin 1 (STANDBY)
of X604 to 5V, then check the
supply power.
bnormal Normal
U24
abnormal
Check the
supply powe
of N606 an
crystal.
Pull out P2 chec
ower
Normal
Short circuit i
a power line
Yes
Normal
Check N501 and
601
bnormal
Power board
roblem
o
Cut off between the power
oard and signal processing,
check the 5V-STB
Cut off the the power
oard and video board
to main board, chec
it
Check 5V-STBY
bnormal Normal
Power board
roblem
Check the power o
201, N601, N204
and N701, crystal an
us.
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.
28
2.With sound but no picture:
y
p
f
N
N
N
N
N
N
N
N
r
b
With sound but no picture
Display LOGO?
Check if no image for all
other channels
o
Check if the white
balance of the factory
menu is normal?
Ye s
Check the N201
and peripheral
circuit
o
Yes
Ye s
Check program
Reset the EEPROM
Check if the X3,
X4 is signal
ormal
Abnormal
Check input signal of N601
and power supply
ormal Abnormal
o
Unfix X3 and X4, turn on the unit
display the white screen
ormal
ormal
Abnormal
Check the suppl
ower (+120) o
backlight board
601
damaged
29
Check N201 and the
circuit of output part
Abnormal
The supply powe
oard damaged
3.With picture but no sound.
t
f
f
t
p
N
f
N
N
No N
f
N
Check if input signal in pin 2 of sound
power amplification
With picture but no sound
o
If there is output from X700 o
sound power amplification board
Sound box damaged
Sound power amp. or other peripheral circui
have problem. Check power supply, i
SHUTDOWN pin control is normal and i
output short circuited or other problems tha
cause protection to work.
R2S15900 or other peripheral
circuit have problem
4. AV no picture
Check if pin 7(AV1) and pin10 (AV2) has signal input
Ye s
Measure if the sound input of the
resent channel corresponding to
400 is normal
o Ye s
Check different levels o
circuit following input audio
signal channel
Check if the pin1 of X4 has signal output
o Yes
400 or other peripheral
circuit have problem
PW2300 or other peripheral
circuit have problem
Check the N201 and peripheral circuit
Ye s
PW218 or other peripheral
circuit have problem
There is problem from Av
socket to N102 channel
30
5. High frequency board overhaul flow
N
t
N
N
N
n
r
m
N
r
5.1 with picture but no sound
Check if other channel is normal
Check if the earphone is normal Check the connection cable
o Yes
Yes
Check if the connectio
cable and power cable is
normal
o
Check the audio powe
amplifier and peripheral.
Yes
The speake
has proble
R2S15900 and peripheral
circuit and earphone socke
have problem
ormal
o
Check if the sound channel
of N400 is normal
Yes
Check the circuit of the all
levels sound channel
o
31
5.2 A certain channel without picture of TV/AV YPBPR
d
m
g
r
(5v,
t
N
N
N
p
N
N
N
Check if the VGA an
HDMI has same proble
o Yes
Check the main board
Ye s
Check if the X600 socket is
normal
o
Check the YPBPR inpu
circuit
S terminal channel AV/TV channel
Check the all levels
circuit of S terminal
YPBPR channel
o
Check if the input pin
o
of N400 has signal
Check the connection cable
and si
Check if the supply powe
Check if the X600 socket is
normal
nal source is normal
9v and 12v) is normal
AV/TV/S channel
Ye s
Check the main board
ormal
o
Check the supply
ower
Check the M52797
and peripheral circuit
32
Ye s
Analog board
Analog board
IR receiver board
power board
APPENDIX-A: Main assembly
Model Part name No.
203.L37T250-21 Button board 667.L37T25-05
Main board 667.L37T7-01C
High frequency board 667.L42T17-55
Power board 667.37FK18-20
Remote control 301.IL37T25-04
Panel 335.37022-00
APPENDIX: Exploded view
333334343535363637373838393940404141
2121 2222 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232
4242
4343
44444545464647474848494950505858 5757 5656 5555 5454 5353 5252
1010 1111 1212 1313 1414 1515 1616 1717 1818 1919 2020
99
88
77
66
5151
44 55
33
22
11
PART LIST OF EXPLODED VIEW
No. PART NO. DESCRIPTION
1 808-10892-AF0 REAR CABINET BAFFLE(LEFT)
2 364-42201-00 SOCKET
3 808-10903-9A0 SOUND BOX REAR COVER(RIGHT)
4 780-Y25LIHAF8A REAR CABINET
5 785-20023-120 SCREW CAP
6 870-3B203-AF0 BUTTON COVER BRACKET
7 743-1B210-AF0 BUTTON DECORATIVE PIECE
8 615-10467-00 TV BOARD SHIELD COVER ASSY(UPPER)
9 808-1A899-AF0 AV BAFFLE(BOTTOM)
10 804-2A402-00 PORT BAFFLE(BELOW TV BOARD )
11 808-1G897-AF0 AV BAFFLE(BOTTOM LEFT)
12 804-2A401-00 PORT BAFFLE(LEFT TV BOARD )
13 ANALOGUE BOARD ASSY
14 615-10468-00 TV BOARD SHIELD COVER ASSY(BOTTOM)
15 808-1A895-AF0 AV BAFFLE(UPPER LEFT)
16 804-2A403-00A PORT BAFFLE(DIGITAL BOARD )
17 CPU BOARD ASSY
18 615-10470-00 DIGITAL BOARD SHIELD COVER ASSY(BOTTOM)
19 615-10469-00B DIGITAL BOARD SHIELD COVER ASSY(UPPER)
20 808-10896-AF0 AV BAFFLE(UPPER RIGHT)
21 870-1A230-00 LCD PANEL CONNECTION BRACKET(UPPER)
22 870-1A234-00 BOARD CONNECTION BRACKET(LEFT)
23 870-10236-00 BOARD CONNECTION BRACKET
24 870-1A237-00 BOARD CONNECTION PIECE
25 870-1A238-00 BOARD CONNECTION PIECE
26 615-10620/10621-00 LCD PANEL TRANS-CONNECTION BRACKET
27 870-1A235-00 BOARD CONNECTION BRACKET(LEFT)
28 870-10380-00 LCD PANEL CONNECTION PIECE
29 864-10225-AW0A SPEAKER NET(RIGHT)
30 780-Y25L1J6A1A FRONT CABINET
31 743-1A187-00A DECORATIVE PIECE
32 808-20343-262 PMMA DECORATIVE BOARD
33 864-10224-AW0A SPEAKER NET(LEFT)
34 877-50498-0T0 BUTTON CAP
35 870-30202-00 BUTTON BRACKET
36 BUTTON BOARD ASSY
37 808-20343-222 PMMA DECORATIVE BOARD
38 870-1A381-00 AV PANEL CONNECTION BRACKET
39 870-10381-00 AV PANEL CONNECTION BRACKET
40 870-1A231-00 LCD PANEL CONNCTION BRACKET(BOTTOM)
41 335-37014-00 DISPLAY SCREEN
42 870-10300-00 BRACKET(AV BAFFLE)
43 870-10241-00 WALL MOUNT BRACKET
44 870-10242-00 WALL MOUNT CONNECTION BRACKET
45 870-10249-00 STAND COLUMN BRACKET
46 808-1B898-AF0 AV BAFFLE (RIGHT BOTTOM)
47 808-10902-9A0 SOUND BOX REAR COVER(LEFT)
48 POWER BOARD ASSY
49 808-10900-AF0 DECORATIVE COVER(LEFT RIGHT)
50 615-20479-00A SPEAKER ASSY
51 870-10289-00 POWER SUPPLY BRACKET
52 360-30042-00 POWER SWITCH
53 808-10901-AF0 DECORATIVE COVER(BOTTOM)
54 808-10812-AF0 POWER COVER COVER
55 808-10893-AF0 REAR CABINET BAFFLE(RIGHT)
56 808-10894-AF0 REAR CABINET BAFFLE(BOTTOM)
57 742-30090-00 LINE CLASP
58 615-10552-00 HOLDER ASSY
603-L37T250-21
Ver.1.0
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