XOCECO LC-27W18S, LC-27W25S, LC-37W25S, LC-42W17S, LC-32W18S Service Manual

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COLOR TELEVISION

LCD-W# series

LC-27W18S, LC-27W25S LC-32W18S, LC-32W25S LC-37W18S, LC-37W25S

LC-42W17S

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CONTENTS

Safety precautions………………………………………………………………………..… Alignment instructions …………………………….…….…………………………….… Method of software upgrading ………………………………………….…….…………… Working principle analysis of the unit……………………………….………….…………. Block diagram…………………………………..……………………………….………… IC block diagram………………………………………………………………………..…… Wiring diagram …………………………………………………………………………….. Assembly list……………………………………………………………………………..… Identification criteria for the bright spot and dark spot of the LCD screen………..…. Troubleshooting…………………………………………………………………………..…… Schematic diagram …………………………………………………………………….…..

1 3 10 13 14 15 19 20 22 23 34

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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

Attention: This service manual is only for service personnel to take reference with. Before

servicing please read the following points carefully.

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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.

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Alignment instructions

1. Test equipment

PM5515 (Video signal generator) PM54200(SCART signal generator) VG-848(YUV, VGA and DVI signal generator) K-7253 (VGA signal generator) CA210 (White balancer)

2. The alignment flow chart (see below figure)

Fig.1 Flow process of alignment

3 Unit adjustments

Method for entering factory menu: Press MENU → -/-- →9→1→8 one by one, then enter factory menu, press the SLEEP button to select adjustment page, exit factory menu to press the MENU button.

Production of data processing board and

analogue board on the line.

Connect to central signal source; check if various

TV functions (station skipping, modulate quantit

control etc), check if the output of earphone and

speaker are normal.

White balance adjustment

Input AV/S signal, SCART and HDTV signal; check various functions under AV/S terminal

Input VGA signal and check if display is normal in

the state of PC and various functions (analog

quantity control, line/field center etc.)

Check DDC and FLASH

Combined test for general assembly and aging

Check accessories and then packing

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4 EEPROM initialization

Enter the first page of factory menu, select “EEPROM INITIALIZE” to be “on”, after turn off the unit, repeating turn on the unit is over.

5 white balance adjustment

Input PAL signal of 16-level gray-scale (TIMING969 PATTAN921) from VG848 to AV channel, enter user menu, set color to 0, APL to “off”, enter factory menu white balance adjustment page, select color temperature, fixed the GGAIN to 50H, adjust BGIAN and RGAIN to 400nits, then the color coordinate to 284, 299. Fixed the BOFFSET to 50H, adjust GOFFSET and ROFFSET to 5nits, then the color coordinate to 284, 299. Select cool tint, adjust color coordinate to 270, 283. Select warm tint, adjust color coordinate to 313, 329.

6. Performance Inspections

6.1 TV function Enter the search menu → auto search, connect RF-TV terminal to the central signal source, check if there is station skipping.

6.2 AV/S input terminal Input AV/S signal, check the picture and sound is normal

6.3 SCART terminal (note: check the SCART terminal, set display mode to AUTO)

6.3.1 Check SCART INPUT special function

6.3.1.1 SCART1 terminal function a. After turn on the unit, connect the SCART1 to PM54200 signal generator, then the unit auto select to SCART1 mode. b. SCART signal generator sends CVBS signal to the unit, check if the image and sound is normal. It sends image format (16:9 and 4:3) to the unit, check if the unit auto identify is normal. Change SCART signal to RGB signal, check if the image and sound is normal, It sends image format (16:9 and 4:3) to the unit, check the unit auto identify is normal. Select the PIP mode, connect earphone cable, and check if the sound is normal.

6.3.1.2 SCART2 terminal function a. After turn on the unit, connect the SCART2 to PM54200 signal generator, then the unit auto select to SCART2 AV mode. b. SCART signal generator sends CVBS signal to the unit, check if the image and sound is normal. It sends image format (16:9 and 4:3) to the unit, check if the unit auto identify is normal, and display the SCART2 AV. Change SCART signal to Y/C signal, select the SCART2 Y/C channel mode, check if the image and sound is normal, It sends image format (16:9 and 4:3) to the unit, check if the unit auto identify is normal. Select the PIP mode, connect earphone cable, and check if the sound is normal.

6.3.2 Check SCART OUTPUT special function

6.3.2.1 SCART1 terminal function Input signal in the TV states, connect the SCART1 terminal to the TV. Change the TV program, check if output signal of SCART1 is TV signal, and the image and sound is normal, change the unit channel, the CART1 output TV signal, it can not other signal.

6.3.2.2 SCART2 terminal function

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Input signal in the TV/AV/S states, connect the SCART2 terminal to the TV. Change the unit channel, check if output signal of SCART2 is current signal, and the image and sound is normal.

6.4 YPbPr/YPbPr terminal Input the YUV signal (VG-848 signal generator), separate input YUV format signal of table 1, check if the image and sound is normal. If the image is deflection of the H-field, select auto sync correction of the SCREEN menu. If the image is slight disturb, adjust the FINE TUNE correction of the SCREEN menu. Open the PIP mode, connect the earphone, and check if the image and sound is normal.

Table 1 YUV format signal

H-frequency(kHz) V-frenquency(Hz) signal 1 15.734 59.94 SDTV 480i

2 31.469 59.94 HDTV 480p 4 44.955 59.94 HDTV 720p 6 33.716 59.94 HDTV 1080i 7 15.625 50 SDTV 576i 8 31.25 50 HDTV 576p 9 33.75 50 HDTV 1080i

10 37.50 50 HDTV 720p

6.5 VGA terminal

Input the VGA signal (VG-848 signal generator), separate input VGA format signal of table 1, check if the image and sound is normal. If the image is deflection of the H-field, select auto sync correction of the SCREEN menu. If the image is slight disturb, adjust the FINE TUNE correction of the SCREEN menu. Open the PIP mode, connect the earphone, and check if the image and sound is normal.

6.6 HDMI terminal HDMI signal format receive the three high definition signal: 480P, 576P, 720P/50/60 Hz, 1080I/50/60 Hz, except for the table 2 signal. Check if the image (contain HDCP ON and OFF) and sound is normal. If the image is deflection of the H-field, select auto sync correction of the SCREEN menu. Open the PIP mode, connect the earphone, and check if the image and sound is normal.

TABLE2 VGA signal format

resolution H-frequency(kHz) V-frenquency(Hz)

Point clock pulse

frenquency(MHz)

remark

1 720 X 400 31.469 70.086 28.322 IBM 2 640 X 480 31.469 59.94 25.175 IBM 3 640 X 480 37.861 72.809 31.5 VESA 4 640 X 480 37.5 75 31.5 VESA 5 640 X 480 43.269 85.008 36 VESA 6 800 X 600 35.156 56.25 36 VESA

7 800 X 600 37.879 60.317 40 VESA 8 800 X 600 48.077 72.188 50 VESA

9 800 X 600 46.875 75 49.5 VESA 10 800 X 600 53.674 85.061 56.25 VESA 11 1024 X 768 48.363 60.004 65 VESA

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12 1024 X 768 56.476 70.069 75 VESA 13 1024 X 768 60.023 75.029 78.75 VESA

14 1280 X 1024 63.98 60.02 108.00 VESA 15 1024 X 768 68.667 84.98 94.486 VESA

6.7 ex-factory setting see to TABLE 3 - TABLE 9

TABLE 3 Factory Option Menus

TABLE 4 Factory Audio Setting

Ex-factory setting

Items

LC-27W18S/27W25S LC-32W25S LC-37W25S LC-42W17S

Volume 1 2CH 2CH 2CH 2CH Volume 25 55H 57H 5AH 5AH Volume 50 5CH 5EH 61H 61H Volume 75 64H 65H 69H 69H Volume 100 6BH 6DH 72H 72H

HP VOLUME SETTING

Volume 1 64H Volume 25 96H Volume 50 A1H Volume 75 AEH Volume 100 BEH MSP Scart1 Volume 72H

Prescale Scart 4CH Prescale FM/AM 27H Prescale Nicam 64H

Scart TV Volume 20H

Scart AV Volume 72H

Items Ex-factory setting

IIC Bus-off Off

EEPROM Erase Off

Backlight Adjustable Off

Back Light 100

Menu Timeout 5

Blank switch enable On

ShowLogo On

Auto Program Sort On

TT Char Group

West Europe / East Europe / Cyrillic / Turkish

/Greek/Arabic/Hebrew Dynamic Scart Off Note: the latter 6 items should set according to clients’ require.

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D/K select HDEV3 Off AVC Off

Equalizer Bands Max 60H Spatial Mode 0 Spatial Strength 00H

TABLE 5 Factory Video limit Setting

Items CVBS SC-RGB YPBPR D-SUB HDMI Bright Min D5H CFH C7H CFH D2H

Bright Middle 00H 00H 03H 05H 07H Bright Max 38H 3DH 34H 3DH 31H

Contrast Min 09H 09H 09H 09H 08H Contrast Middle 20 25H 20H 25H 23H Contrast Max 2AH 31H 29H 31H 2CH

Sharpness Min 00H 00H 00H 00H 00H Sharpness Middle

10H 10H 10H 10H

10H

Sharpness Max 1FH 1FH 1FH 1FH 1FH

Color Min 00H 00H 00H 00H 00H

Color Middle 1DH 1DH 1DH 1DH 1DH Color Max 2DH 2DH 2DH 2DH 2DH

Hue Min 80H 80H 80H 80H 80H Hue Middle 20H 20H 20H 20H 20H Hue Max 7FH 7FH 7FH 7FH 7FH

TABLE 6 White Balance Adjust

Items LC-27WXXS LC-32WXXS LC-37WXXS LC-42WXXS R Offset 55 55 54 53 G Offset 51 53 57 49 B Offset 50 50 50 50 R Gain 42 36 36 37

G Gain 50 50 50 50 B Gain 21 40 51 38 Brightness 51 51 51 51 Contrast 100 100 100 100 Color Temperature Standard

R Offset 60 59 58 55 G Offset 55 55 58 52

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B Offset 50 50 50 50 R Gain 35 25 24 32

G Gain 50 50 50 50 B Gain 28 48 61 48 Brightness 51 51 51 51 Contrast 100 100 100 100 Color Temperature Cold

R Offset 55 49 49 44 G Offset 53 51 53 47 B Offset 50 50 50 50 R Gain 62 51 58 66 G Gain 50 50 50 50 B Gain 8 23 33 22

Brightness 51 51 51 51 Contrast 100 100 100 100 Color Temperature Warm

TABLE 7 Image analog setting

CVBS Vivid Standard Mild Custom Contrast 90 80 50 80

Brightness 40 35 35 35 Color 70 60 40 60 Hue 00 00 00 00 Sharpness 60 50 30 50

SC-RGB Vivid Standard Mild Custom Contrast 90 85 50 85

Brightness 60 50 35 50 Color 80 65 40 65 Hue 00 00 00 00 Sharpness 60 50 30 50

YPBPR Vivid Standard Mild Custom Contrast 90 85 50 85

Brightness 50 40 35 50 Color 80 65 40 65 Hue 00 00 00 00 Sharpness 60 50 30 50

D-SUB Vivid Standard Mild Custom Contrast 90 80 50 80

Brightness 50 40 35 40 Color 80 65 40 65 Hue 00 00 00 00 Sharpness 60 50 30 50

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HDMI Vivid Standard Mild Custom Contrast 90 80 50 80

Brightness 50 35 35 35 Color 80 70 40 70 Hue 00 00 00 00 Sharpness 60 50 30 50 Note: in factory menu states, it can change the factory mode to value of the image and sound, else select the image and sound balanced value in the other states.

TABLE9 SOUND equilibrium value setting

Live Pop Rock Custom 120 Hz 50 50 65 50 500 Hz 50 50 55 50

1.5 kHz 50 60 55 50 5 kHz 80 70 55 50 10 kHz 85 70 55 50

6.8 Ex-factory setting of user menu

6.8.1 select TV channel

6.8.2 video menu, Mode: Standard, NR: Medium, APL:ON

6.8.3 sound menu, Volume: 20, Balance: 00, Equalizer: Custom, HP Volume: 20;

6.8.4 edit menu, Color System: Auto, Sound System: DK;

6.8.5 option menu, Default Zoom: Auto, Child Lock: Off, Menu Language: English, Country: UK, WSS: OFF, Blue Screen: On. Note: the 6.8.4 and 6.8.5 items should set according to clients require.

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Method of software upgrading

1. Enter the software upgrading state of the TV Method 1: press the VOL- button in the unit, turn on the main power switch, then the screen

display black screen, but the indicator to blue.

Method 2: Enter factory menu, select the IIC-BUS OFF item.

2. Connection upgrading tools with upgrading port.

3. Dual- click IAPWriter logo, enter the upgrading states (if the PC and the IIC communication

trouble, it can prompt.

4. Select the file menu load the software follow as:

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5. Select WRITE DEVICE item of the device menu, till the right screen display “DONE”.

6. turn off the power , restart the unit. Note: because of the software, it may be no-stabilization, the software can auto download and write.

Connection cable

Upgrading tools

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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.

Upgrading port

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Working principle analysis of the unit

1. Analog signal flow Antenna reception signal send to integrative tuner (contain HF and IF amplifier circuit), the tuner is controlled the command (SDA and SCL) of the MCU N301 (M16C), select appropriate channel to system switch, via HF amplifier and IF amplifier decode, output video signal of 2VPP and sound signal of 1VPP. Sound signal (SCART1, 2 sound, AV sound, YPbPr, HDMI and D-SUB) via N581 HEF4052BT (sound diverter switch) to output signal, it send to N801(MPS3410 sound processing and volume control) switch of audio. Select right/left sound channel, their send to digital sound amplifier N803 (TPA3008) amplify, then send to speaker. After output video signal of tuner, SCART1 video signal and RGB signal via matched resistance, the signal thought alone channel send to main decode IC(N101 SVP-EX52) video switch, A/D transition, digital decode, image scale and OSD superposition, then send to LVDS level drive for LCD screen. AV, S-Video, SCART2 video and Y/C signal thought matched resistance, the signal send to the N506 video switch (SN74CBT3257CDR), via switching to selected signal (EX52_Y and EX52_C) to main decode IC (N101 SVP-EX52) video switch, A/D transition, digital decode, image scale and OSD superposition, then send to LVDS level drive for LCD screen. D-sub and YPbPr signal thought matched resistance, the signal send to the N507 video switch (SN74CBT3257CDR), via switching to selected signal (EX52_YUV) to main decode IC (N101 SVP-EX52) video switch, A/D transition, digital decode, image scale and OSD superposition, then

send to LVDS level drive for LCD screen.

2. Digital signal flow: HDMI signal thought HDMI reception chip N405 (SiI9011HDMI with HDCP function), after receive, output digital format signal send to SVP-EX52 PIP channel thought image scale and OSD superposition, then send to LVDS level drive for LCD screen. The HDMI chip output audio digital format signal change to analog sound signal from N403 (CS4344 audio DA transfer chip), then N581 switched to N801 (MPS3410 sound processing and volume control).

3. TELETEXT function This unit adopt main decode IC N101(SVP-EX52) of Trident company, it has TELETEXT decode function, after decoded, the teletext information in OSD display.

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Block diagram

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IC block diagram

1. Sound processing IC (MSP3410)

Sound signal send to sound processing N801 MSP3410, and dual-circuit tuner has second SIF, it sends to N801 (stereo decode and auto volume control), N801 has audio channel switch, after switching in N581 (HEF4052BT), the audio input of VGA/HDMI/YPbPr will be sent to N801 together with the audio signal of TV and AV to do the switching process. A way signal thought volume and high-low sound controlled, output the left and right audio send to digital audio amplifier N803 (TPA3008) amplify, then it send to speaker, other way signal output left-right audio send to earphone amplifier N805 (NJW1109), after audio control and power amplifier, it output to earphone socket. Other two ways signal output audio of TV out and AV out by SCART terminal of video board.

MSP3410 internal block diagram as follow:

Main pins instructions: 2, 3: SCL, SDA 27, 28: left-right audio of audio power amplification 36, 37: left-right audio of earphone 24, 25: left-right audio of AV OUT 33, 34: left-right audio of TV OUT 47, 48: left-right audio from main board 50, 51: left-right audio of SCART2 53, 54: left-right audio of SCART1 56, 57: left-right audio of AV IN 67, 69: SIF input of sub-channel and main-channel TV 59: MONO input of sub-channel TV

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2. Sub-channel and SCART video signal decode IC (TVP5147)

Sub-tuner TUNER202 decode video, AV, S-VIDEO, SCART1 video, SCART2 video and Y/C signal, after matching impedance, enter decoding IC N601 (TVP5147), so the PIP image of sub-channel can selecting arbitrary video signal.

MSP3410 internal block diagram as follow:

TVP5147 main pins instructions: 28, 29: SCL, SDA 22: Video input for SCART1 7, 80: Y/C signal input for SCART2 16: video signal input of sub-tuner 8: Y signal input of AV or S-Video 1: C signal input of S-Video 9, 2, 18: YUV signal input of compatible DTV

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3. Reception HDMI signal (SiI 9011)

After differential signal of HDMI send to N405 (SiI9011), then it transform 24bit for video digital signal, and sent to IC N101 (SVP-EX52) processing.

SiI 9011 internal block diagram as follow:

4. Main decode and processing IC(DPTV-SVP-EX52)

SVP-EX52 internal block diagram as follow:

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SVP-EX52 main pins instructions:

14, 16: SCL, SDA 10, 11: VGAHS, VGAVS input, 244, 231: EX52_Y and EX52_C input 243: main tuner video signal input 242: video signal input for Scart1 226, 248, 233: Scart1 RGB input 246, 232, 225: EX52_YUV input 236, 237: video output for SCART2

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Wiring diagram

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Assembly list

LC-27W18S/LC-27W25S

Name Part No. Main IC and No.

Data processing board 667-L27W18-69 N101 DPTV-SVP-EX52 (353-DPTV0-20)

N201 K4D2632838F (353-26323-10)

N302 W29C040P-90B (353-29040-30)

N301 M30620SPGP (353-30620-20)

N601 TVP5147PFP (353-51470-10)

N405 SiI9011CLU (353-90110-10)

N403 CS4344CZZ (353-43440-10)

Audio processing board 667-L27W18-15 TUNER201 JS-6B2/122A2-A2 (590-40512-00)

TUNER202 JS-6B2/121A2 (590-40511-00)

N801 MSP3410G (353-34100-80)

N803 TPA3008D2 (353-30080-10)

N805 NJW1109M (353-11092-20)

Video processing board 667-L27W18-40

IR reception board 667-L27W18-09

(LC-27W18S)

Button board 667-L27W18-05

(LC-27W18S)

667-L32W25-05

(LC-27W25S)

Power supply board 667-L27W18-20

LC-32W18S/LC-32W25S

Name Part no. Main IC and no.

Data processing board 667-L32W25-69 N101 DPTV-SVP-EX52 (353-DPTV0-20)

N201 K4D2632838F (353-26323-10)

N302 W29C040P-90B (353-29040-30)

N301 M30620SPGP (353-30620-20)

N601 TVP5147PFP (353-51470-10)

N405 SiI9011CLU (353-90110-10)

N403 CS4344CZZ (353-43440-10)

Audio processing board 667-L32W 25-15 TUNER201 JS-6B2/122A2-A2 (590-40512-00)

TUNER202 JS-6B2/121A2 (590-40511-00)

N801 MSP3410G (353-34100-80)

N803 TPA3008D2 (353-30080-10)

N805 NJW1109M (353-11092-20)

Video processing board 667-L27W18-40

IR reception board 667-L32W18-09

(LC-32W18S)

Button board 667-L27W18-05

(LC-32W18S)

667-L32W25-05

(LC-32W25S)

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Power supply board 667-L32K5-20A

LC-37W18S/LC-37W25S

Name Part no. Main IC and no.

Data processing board 667-L37W25-69 N101 DPTV-SVP-EX52 (353-DPTV0-20)

N201 K4D2632838F (353-26323-10)

N302 W29C040P-90B (353-29040-30)

N301 M30620SPGP (353-30620-20)

N601 TVP5147PFP (353-51470-10)

N405 SiI9011CLU (353-90110-10)

N403 CS4344CZZ (353-43440-10)

Audio processing board 667-L32W 25-15 TUNER201 JS-6B2/122A2-A2 (590-40512-00)

TUNER202 JS-6B2/121A2 (590-40511-00)

N801 MSP3410G (353-34100-80)

N803 TPA3008D2 (353-30080-10)

N805 NJW1109M (353-11092-20)

Video processing board 667-L37W25-40

IR reception board 667-L37W18-09

(LC-37W18S)

Button board 667-L37W18-05

(LC-37W18S)

667-L37W25-05

(LC-37W25S)

Power supply board 667-L37K5-20C

LC-42W17S

Name Part no. Main IC and no.

Data processing board 667-L42W17-69 N101 DPTV-SVP-EX52 (353-DPTV0-20)

N201 K4D2632838F (353-26323-10)

N302 W29C040P-90B (353-29040-30)

N301 M30620SPGP (353-30620-20)

N601 TVP5147PFP (353-51470-10)

N405 SiI9011CLU (353-90110-10)

N403 CS4344CZZ (353-43440-10)

Audio processing board 667-L32W25-15 TUNER201 JS-6B2/122A2-A2 (590-40512-00)

TUNER202 JS-6B2/121A2 (590-40511-00)

N801 MSP3410G (353-34100-80)

N803 TPA3008D2 (353-30080-10)

N805 NJW1109M (353-11092-20)

Video processing board 667-L42W17-40

IR reception board 667-L42W 17-09

Button board 667-L42W17-05

Power supply board 667-L42W17-20

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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

spot

≤5 ≤2 ≤5 ≤2 ≤3

Two

neighboring

spots

≤2 ≤1 ≤2 ≤1 ≤1

Bright

spot

Total N o . ≤5 ≤2 ≤5 ≤2 ≤3

≥15mm

One single

spot

≤6 ≤7 ≤5 ≤4 ≤10

Two

neighboring

spots

≤2 ≤2 ≤2 ≤1 ≤5

Dark

spots

Total N o . ≤6 ≤7 ≤5 ≤4 ≤10

≥15mm

≥10mm ≥5mm

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).

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Tr ouble 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

 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.

There appear streaks or light color

on the screen

 Check if interfered by other equipment and if interfered

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

tone

 Check if all the picture setups have been corrected.

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

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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.

 Check if the cable is disconnected.

 Check if it’s connected to the proper terminal or if the input

mode is correct.

There appears an indication -

“outside the receivable scope)

 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

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2. Troubleshooting guide

Yes, turn the unit on

Yes

( 1) , No raster, no picture and no sound

Is the power indicator lights? Yes No

No Yes Normal Abnormal

Abnormal Normal Normal Abnormal

Connect the power

A red indicator lights?

Check Power supply, infra-red board, CPU an

its periphery circuit (flash) and power cord

A blue indicator lights?

Check if the pin 42 of CPU is square-wave; check the periphery circuit of CPU and FLASH/SRAM

oes bac

klight light up

Check backlight board, CPU pin 77-backligh

control condition.

Check if the display of eac

channel’s video signal is normal

Check the signal inputted from the channel to pin IC

is normal or IC and its periphery is normal or th

output of LVDS is normal

Check if the display of eac

channel’s audio signal is normal

Check the signal inputted from the channel to pin IC is normal or IC(TPA3008D2/MSP3410) and its periphery is normal

o raster, no picture and no sound

Check Standby5V

Is the blue indicato

lights?

Disconnect the power supply board

with the data processing board, an

then measure Standby5V

Disconnect CN902, and the

find out that which part fails to work properly

The powe

supply boar

fails to wor

properly

Check I2C bus of the system

Check the power supply of CPU(N301) an

FLASH(N302)

Check the capacitor o

L301 and the periphery o

CPU and FLASH

Check the pin 10 of CPU is hig

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Yes No

No Yes

NOTE: When pin 10 of N301 is low level, remove V301 and then check the correspondent pins of

N301are high level or not, the reset circuit fails to work properly if it is high level. If pin 42 of N301 has

no square-wave, remove R365, if the square-wave appears, then it is probably the FLASH of N302 fails

to work properly. When it comes to check the periphery circuit of N301, N302 and N303, use

oscilloscope to check the connecting resistor’s pin among N301, N302and N303 besides checking the

connection of correspondent components, if regular square-wave or no signal is found, then it represents

that one of N301, N302 or N303 fails to work properly, probably is N302. If R110 and R111connects

N301 with N101fails to work will also lead to the failure phenomenon.

( 2) No picture but with sound( blue screen and OSD appear)

Yes No

NOTE: Please refer to checking procedure (5) to get the methods for checking the phenomenon of no picture but with sound of HDMI channel

Check N301 and its reset circuit，especiall

check the critical components namel

Check if pin 42 o

301is square-wave

Check N301 and its crystal oscillation

Check the periphery circuit of

301,N3022 and N303

o picture but with soun

Whether backlight lights up.

Check if other channels have no

icture

Check N101 an

its periphery

Refer to (4) checking

rocedure

Check backlight board, CP

pin 77 backlight control

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( 3) No picture but with sound( only backlight lights up)

Normal Abnormal

Yes No

NOTE: Because the power supply for 37” LG LVDS is 12V check N715 for 37” and check N705 for other models

(4), No sound but with picture

No Yes

Yes No

o sound but with picture

Check if the sound processing board X804 has output

Speaker fails to work

Check if correspondent pins of powe

amplifier have output

Sound only with raster

Check if the power supply o

LVDS is normal or not

Check the signal outputted from

101 to X189 is normal or not

The receiving board of

LVDS fails to wor

properly

Check the power supply and the periphery circuit of N101

Check pin 5 of N705 or pin 2 and 4 of N715 is low level or not

Check the periphery circuit of N705 o

eriphery circuit of N715

Check pin 76 of N301 and the inverter circuit, which it crosses

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No Yes

Yes No

( 5) , A certain channel fails to work properly

a), AV with no picture

Yes No

b), S terminal with no picture

Yes No

Check periphery circuit

of power amplifier’s back level

Check if there have signals

inputted from R827 and R824 to power amplifier

Check periphery circuit of powe

amplifier, power supply circuit an

circuit of pin MUTE

Check if corresponden

channels of N801 have input signal

Check periphery circuit of

N801，crystal oscillation and power supply circuit

Follow the direction of audio

signal input to check eac

channel

Check if C164 has input signal

Check if pin 2 of N506 has input signal

Check if C164 and C165 have input signal

Check periphery circuit of N101, crystal oscillation and powe

supply circuit

There exits problems at the

lace from socket of A

terminal to N506

Check periphery circuit o

506 and power supply circui

Check periphery circuit of N101, crystal oscillation and power suppl

circuit

Check if pin 2 and pin 6 of N506 have input signal

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Yes No

c), TV channel with no picture

Firstly find out which frame fails to work properly making use of the PIP function, PIP frame or Main

frame.

Main frame with no picture:

Yes No

PIP frame with no picture:

Yes No

Check if pin 12 o

TUNER201 has input signal

Check if C163 has input signal

Check the circuit between TUNER201 an

101

Check peripher

circuit o

TUNER201, powe

supply circuit an

bus

Check if pin 12 of TUNER202 has output signal

Check if the horizontal and vertical synchronous signal , clock signa

outputted from N601 are normal or not

Check if pin 16 of N601 has inpu

signal

There exits problems at the

lace from socket of S terminal

to N506

Check periphery circuit o

506 and power supply circuit

Check periphery circuit of N101, crystal oscillation and powe

supply circuit

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Yes No Yes No

d) No picture in SCART1 mode

Yes No

e) No picture at SCART2 mode

Check N601 surrounding circuit, crystal oscillation an

power supply.

Check the circuit between TUNER202 and N601.

Check TUNER202 surrounding circuit, powe

supply and bus

Check

101 surrounding circuit, crystal oscillation an

power supply.

Measure whether there is signal input to C162,C183,C184,C185

There is trouble at the path from SCART1 socket to

101.

Measure whether there is signal input to C164, C165.

Check whether the connectio

between SCART1 socket pin 16 and X807 pin 9 is normal.

Switch the signal between SCART1 RGB

and VIDEO input, measure N301 pi

87 to check whether there is level

han

ge.

The trouble is at Resistor R877.

Check N101 surrounding

circuit, crystal oscillation and power supply.

Check N501 surrounding circuit

and power supply.

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Yes No

f) No picture at YPbPr or YCbCr mode

Yes No

No Yes

g) No picture in D-Sub mode

Yes No

Measure whether there is signal input to C173,

C174, C175.

Measure whether there is signal output fro

507 pin 4, pin 7 and pin 9.

Check whether there is signal input to N507 pin 2, pin 5 and pin 11.

Check the path from N507

output to N101 input.

Check N507 surrounding circuit an

power supply.

There is trouble at the pat

between YpbPr socket an

507.

Input YpbPr signal and check whether the display is normal.

Check N101 surrounding circuit, crystal oscillation an

power supply.

Measure and check whether there is signal input to

506 pin 3 and pin 6.

There is trouble at the path from SCART2 socket to N506.

Check N506 surrounding circuit an

ower supply

Check N101 surrounding

circuit, crystal oscillatio

and power supply.

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Yes No

h) No picture in HDMI mode

Yes No

I) No sound in HDMI mode

No Yes

Check according to procedure (f)

Check whether the H&V sync signal, clock signal output from N405 are normal.

Check N405 surrounding circuit, power supply and the connection to HDMI socket is well-going.

Measure whether N101

pin10, pin 11 have Sync signal input.

There is trouble at the path between VGA socket an

507.

Measure whether there is sync signal input to N501 pin 1 an

pin 5

Check N501 surrounding circui

and power supply.

There is trouble at the path between VGA socket an

501.

Check N101 surrounding circuit , crystal oscillation and power supply.

Check and measure whether X583 pin 1 an

pin 2 output signal.

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Yes No

Check according to procedure

(4).

Measure and check whether N581 pin

1, pin 12 have signal input.

Check N581 surrounding

circuit and powe

supply.

Check whether N403 pin7 and pin10 have outpu

signal.

Check the pat

between N403 and

Check whether

403 pin1&2&3&4

Check N403 surrounding circui

and power supply.

Check according to

rocedure (h

)

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Schematic diagram

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