Xoceco LC-42FE32 Schematic

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LCD TELEVISION

LC-42FE32

CONTENTS

Safety precautions………………………………………………………………………..…

Alignment instructions …………………………….…….…………………………………

Working principle analysis of the unit……………………………….………….………….

Block diagram …………………………………..………………………………….…………

IC block diagram………………………………………………………………………..……

Wiring diagram …………………………………………………………………………….

Troubleshooting….…..………………………………………………………………..……

Schematic diagram…………………………………………………………………………

APPENDIX-A: Assembly list

APPENDIX-B: 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

would be unable to work and no way to get it repaired. If the connection wires, connectors or components fixed by the thermotropic glue need to disengage when service, please soak the thermotropic glue into the alcohol and then pull them out in case of damage.

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.

Alignment instructions

1. Test equipment

Digital Multi-meter 54200 (Signal generator) PC (FLASH writing programs have to be installed first, W24CXX.EXE) VG849 (HDMI signal generator) CA210 (White balancer) DVD player (with HDMI output) Monitor

2. The alignment flow chart (see below figure)

Production of main board, high frequency board,

other little board, power board on the line.

ADC emendation and white balance adjustment

Connect to central signal source, check various TV functions (station search, system identify, modulate quantity control etc), check if the output of earphone and speaker are normal Picture and sound of AV-out is normal. (check stereo/SAP and CCD, VCHIP for America) .

FLASH write N5, N9, N13, N24

High frequency board test

Main board test

Test of Button board and IR board

Combined test for general assembly

Aging

Fig.1 Flow process of alignment

Check accessories and then packing

Input VGA signal, check if display is normal in

the state of PC and various functions (analog

control), line/ field center etc. the picture and

sound of AV-OUT should be the picture and

sound of the current channel

Input HDMI and DVI signal (use a connection

wire, input audio signal from D-sub Audio in),

check if HDCP KEY, picture and sound are

normal.

the picture and sound of AV-OUT should

be the picture and sound of the current channel

Input YPbPr/YCbCr 1/2 signal and check if

picture, sound and analog quantity control is

normal in the state of COMPONENT. the picture

and sound of AV-OUT should be the picture and

Input AV1/S/AV2 signal, check various functions under each terminal (system identify, analog control etc), check if Picture and sound of AV-out is normal. (S-terminal and AV1 share the same audio channel, the output picture from AV-out is the picture of AV1 in the status of S-terminal)

3. Flash writing programs

Flash write N5, N9, N13, N24 Flash write W24CXX.EXE to N13, N24 with self-made flash write tool on the line. Note: software upgrade of N5 from socket X51

software upgrade of N9 from USB interface software upgrade of N13, N24 from HDMI and VGA interface separately

Adjustment of main board and high frequency board

a) Connect the main board and high frequency board according the wiring diagram. Connect X402

(on main board) with IR board and insert the plug of power supply assy into X707, now the indicator light of IR board is red.

b) Press POWER button on the remote control set, now the indicator light of IR board is blue.

c) Check if picture and sound are normal of all the channels, if STEREO/SAP can be identified

correctly. Check AV-OUT function: the picture and sound of AV-OUT should be the picture and sound of the current channel at TV/AV1/S/AV2; the sound from AV-OUT should be the sound of the current channel at the other signal source, while the picture don’t need to check.

4. Unit adjustment

4.1 Adjustment of unit connection

Turn on the TV and check if it is normal: display LOGO about 8 seconds later, display picture about 12 seconds later.

4.2 Aging

a) Turn on the TV, select TV channel without signal input.

b) Aging for an hour in the aging room.

4.3 ACD calibration and White balance adjustment (use CA210, VG849 generator)

Method of entering factory menu: enter “INPUT” menu, then press”2 5 8 0” one by one.

Note: Coordinate of cold color temperature 9300K is (X=283, Y=299), coordinate of warm color temperature 6500K is (X=311, Y=329).

YPbPr channel (YPbPr1 or YPbPr2)

a) Input SMPTE COLOR BAR signal of 480P (TIMING:976, PATTERN:984)

b) Set brightness to 50; contrast to 50

c) Enter factory menu and perform “Calibration”

VGA channel

a) Input 16-level gray scale signal of the mode 800*600 @60 (TIMING:885, PATTERN:920)

b) Set brightness to 50; contrast to 50

c) Enter factory menu and perform “Calibration”

d) Select “color temperature” of “COOL”

e) Enter “color temperature setting” menu

f) Fix GREEN GAIN at 128, adjust RED GAIN, BLUE GAIN to set the color coordinates of

fourteenth level to (X=283, Y=299).

g) Set the color coordinates of warm color temperature (WARM) to (X=311, Y=329) using the

same method.

h) Check if the color coordinates of the cool/warm color temperature at YPbPr (include 480i,

480P, 720P, 1080i), VIDEO(NTSC, PAL) and TV channels are within the scope of the corresponding value (permit ±8 error).

5 Functional Inspection

5.1 TV function Connect RF terminal to the central signal source, Enter Search menu → auto search, check if there is station skipping. Check if Fine Tune, the output of earphone and speakers, and the picture are normal. Check STEREO/SAP/CCD/Parent Control and the picture and sound from AV-OUT.

5.2 ATSC function Connect AIR terminal to the central signal source, press INFO button and check if the information is right. Open EPG table and do the same check. Open CCD, V-CHIP and check the display.

5.3 AV/S-Video terminal Separate input AV1/S/AV2 signal, check if they are normal. Check if the picture and sound from AV-OUT is normal. It should auto-jump to S terminal when insert S-terminal at the status of AV1.

5.4 VGA terminal Input VGA signal (VG849 signal generator), separate input the VGA format signal of table 1 and check if the display and sound are normal. If the image is slight disturb, press auto correction button on the remote control and check the display.

Table1 PC signal format

No Resolution H-frequency(kHz) V-frenquency(Hz)

1 720×400 31.47 70.08 25.17 DOS

2 640×480 31.50 60.00 25.18 DOS

3 640×480 37.90 72.00 31.50 Mac.(SOG)

4 640×480 37.50 75.00 31.50 VESA

5 640×480 43.30 85.00 36.00 VESA

6 800×600 35.16 56.25 36.00 VESA

7 800×600 37.90 60.00 40.00 VESA

8 800×600 46.90 75.00 49.50 VESA

9 800×600 48.08 72.19 50.00 VESA

10 832×624 49.00 74.00 57.27 Mac.(H+V)

11 1024×768 48.40 60.00 65.00 VESA

12 1024×768 56.50 70.00 75.00 VESA

13 1024×768 60.00 75.00 78.75 VESA

14 1280×1024 64.00 60 108.00 SXGA

15 1280×1024 80.00 75 135.00 SXGA

5.5 YPbPr terminal Input YPbPr signal (VG849 signal generator), separate input the format signal of table 2, check if the image and sound is normal. If the image is slight disturb, press auto correction button on the remote control and check the display.

Point clock pulse frenquency(MHz)

Remark

Table 2 Component mode

No Resolution H-frequency(kHz) V-frenquency(Hz)

720×480 15.734 59.94 13.5 480i(NTSC)

2 720×576 15.625 50 13.5 576i(PAL)

720×480 31.469 59.94 27 480p(NTSC PROG)

4 720×576 31.25 50 27 576p(PAL PROG)

1280×720 45 59.94 74.18 720p(59p)

6 1280×720 45 60 74.25 720p(60p)

1280×720 37.5 50 74.25 720p(50p)

8 1920×1080 33.75 59.94 74.25 1080i(59i)

1920×1080 33.75 60 74.25 1080i(60i)

10 1920×1080 28.125 50 74.25 1080i(50i)

5.6 HDMI terminal Input HDMI signal (VG849 signal generator), separate input the format signal of table 3 and table 4. Check if the image and sound is normal. Input DVI signal through DVI-HDMI trans-connection wire, input audio signal from DVI/VGA AUDIO and check if it is normal.

Table 3 HDMI signal format

No H-frequency(kHz) V-frenquency(Hz) Remark

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

Table 4 HDMI audio signal format

Channel 2

Sampling frequency 32 Kbit/s, 44.1 Kbit/s, 48 Kbit/s

Wide 16 bit, 20 bit, 24 bit

Point clock pulse frenquency(MHz)

Remark

6 Ex-factory preset

Enter the factory menu in the status of TV, then perform the ex-factory preset.

7 Packing

Check the accessories and then packing.

Working principle analysis of the unit

1. Video signal flow (see below figure) TV VIDEO signal(TV1, TV2) output from TUNER1 and TUNER2 is divided into two ways, one way is sent to PW328 process of main-picture; another way is sent to TVP5147 process of sub-picture. Likewise, analog video signal of AV1, AV2, Y/C is divided into two ways and separate sent to PW328 and TVP5147 to do the same process. In addition, 44MHZ digital IF signal output from TUNER1 is sent to N717 demodulating for TS(0:7), then it send to PWM2000 to do the corresponding process, then switch to RGB of 30bit output to PW328, the signal of TV1,TV2, AV1, AV2, Y/C input into TVP5147 digital processing and convert into 20bit YC signal output to PW328; while digital signal of YPbPr1,YPbPr2 and VGA send straight to PW328. The differential signal of HDMI-1 and HDMI-2 via HDMI receiver SIL9011 after, demodulate 30bit RGB signal output to PW328 too. The all signal input into PW328 digital processing then send to LVDS level drive for LCD panel. In addition, TV1, TV2, AV1 and AV2 via QS3257 select after, send to X704 for output of video.

Tuner 1

Tuner 2

V-out

Tuner 1

AV 1

AV 2

YCbCr

YPbPr 1

YPbPr 2

VGA

HDMI-1

HDMI-2

TV1

TV2

3257

T312

VSB/QAM

Demodulator

30-BIT RGB

PWM328

SiL9011

PWM2000

TVP5147

20-BIT Y/C

LVDS

30-BIT RGB

2. Audio signal flow (see below figure) SIF1, SIF2 of TUNER1 and TUNER2 send straight to MSP4440G demodulate of MTS. The signal and the sound of AV1, AV2, VGA and YPbPr1, YPbPr2(via PIV331 to select signal),send to MSP4440G select output. CL/WS of HDMI-1, HDMI-2 and digital MEPG_CL/WS demodulated from PWM2000 via 3257 select after, it send to MSP4440G, while the data D1 and D2 of HDMI and PWM2000 send straight to MSP4440G. IIS and the audio signal of each channel are demodulated in MSP4440G then sent to TPA3008 amplify and output. The audio signal of TS stream may be demodulated and converted into SPDIF to output in PWM2000 at the same time.

Audio out

Tuner 1

SIF1

SIF2

Tuner 2

AV 1

AV 2

VGA

MSP4440G

PIV331

3257

IIS D1

Mepg cl/ws

Hdmi cl/ws

IIS D2

PWM2000

SiL9011

YPBPR 1

HDMI-1

YPBPR 2

HDMI-2

I2C

Block diagram

DDR

128M

FLASH

4MBITS

DDR

64M

MASTER

TV1

PWM2000

CPU

MPEG 2 decode

T312

TUNER1

slowbus

30bit RGB

PWM328

SCALER

20BIT Y/C

lvds

Panel

RS-232

TV2

TUNER2

TVP5147

DECORDER

AV 1 / S

30BIT RGB

PIV331

YPrPb1

YPrPB2

2X amplify V-OUT

HDMI/DVI-2

IR Key

PIV331

ATMEGA8L

SII9011

HDMI

receiver

Note:

HDMI/DVI-1

VGA

Earphone

Video signal

Audio signal

I/O signal

Digital audio signal

HD signal

Digital signal

Speaker

MSP4440

Sound processor

TPA3008

Sound amplify

Earphone

NJM1109

Earphone amplify

IC block diagram

1. PWM2000

Feature:

 Main frequency of RSIC CPU up to 200MIPS  USB controller  MPEG2 decoder  Intelligent controller  Audio decode, supports formats of all kinds. In this system, it decodes TS audio signal,

supports SPDIF output.

Pin descriptions:

Pin Type Name Instruction

AN8 IRQ5 IR2000 Remote reception

AK9 IRQ1 EXTINT_328 V-sync send to PWM2000 judge of

signal

AK10 IRQ0 INTENETn Net adjustment board interrupt

(DEBUG emulation)

AK11 PIO17 VO_SEL0

AN10 PIO20 VO_SEL1

AK13 PIO9 AUDIOSEL Select HDMI/MPEG I2S output

AL13 PIO8 AUDIOSEL_Y Selection of YPBPR input audio

AL12 PIO11 BK_ON Backlight control: 0=OFF 1=ON

AK12 PIO10 LCD_ON Power supply control of panel:

AM11 PIO15 HOT_PLUG Hot-plug control

AM13 PIO7 OSCOFF A/D conversion of main tuner

AN13 PIO6 SID Detect of SVIDEO input (SVIDEO

AN14 PIO5 MUTE Control of mute

AK14 PIO20 RF_SW Select RF input (AIR/CABLE)

Selected video output (TV1, TV2, AV1, AV2)

0=OFF 1=ON

prior)

2. PWM328

Feature:

 Supports V-CHIP, CCD, OSD  DEIMTERLACING  SCALING  PIP/POP  Integrated ADC, VIDEO DECODER

Block diagram is follow:

Pin descriptions:

Pin Type Name Instruction

M1 PORTA0 SBBE0

M2 PORTA1 SBBE1

D24 ADC0 KEY1_328

Enable control of bus line of bit store

Button

C26 ADC1 KEY2_AD_IN

A10 PWM0 BRIGHT Brightness of backlight control

Description of main periphery components: R62: amplitude adjustment of LVDS output, the resistance bigger, the LVDS amplitude smaller. R259: DDR clock matching resistor for PWM328. in this system, DDR clock up to 180MHZ. The

resistor is 0ohm for compatible 200MHZ. R263-R269: DDR matching resistor R721, R724: matching resistor for HD synchronizing separator circuit C268: isolating capacitor for SOG separator circuit of VGA signal R478: matching resistor of SLOWBUS 50MHZ clock signal

3. TVP5147

Feature:

 VEDIO DECORDER of sub-picture  BT 601 20-BIT 4:2:2 YCbCr output

Block diagram is follow:

Description of main periphery components:

C19, C20, C22, C23, C27: isolating capacitor for video input R18: I2C sub-address select pin R19: connect to the ground to insure the signal format output of BT.601 R22: indicator pin of odd-even bit output: select pin of BT.601 signal format output

4. SII9011

Feature:

 HDMI1.1 and DVI1.0 compatible receiver, integrated HDCP1.1  Supports digital interface of all kinds, this system supports 30bit RGB output  Color space convert  Four channels I2S outputs, sampling frequency up to 192KHZ  Audio protection

Block diagram is follow:

5. ATMEGA8L

Feature:

 STANDBY power supply control  WATCHDOG manual reset  Remote, button reception  Indicator light control

The ATMEGA8L is an 8bit of high performance and low power consumption AVR single chip of ATMEL .

6. MSP4440G

Feature:

 Multistandard sound process  Multi-channel output, SPDIF output  Interface of internal/external audio delay  AVC(AUTOMATIC SOUND DORRECTION)  I2S digital audio output

Block diagram is follow:

7. MK3771

Feature:

 Analog pulse generator  Generate all kinds of frequency, the system needs frequency of 54MHA, 74.175MHZ

provided for PWM2000.

Logic table is follow: B and C Clocks (MHz)

BS1 BS0 CS BCLK CCLK1 CCLK2

0 0 0 74.175 20 25

VCSL Clocks (MHz)

VS VCLK1 VCLK2 VCLK3 VCLK4

0 27 27 27 108

M 27 54 13.5 108

1 27 27 27 27

Block diagram is follow:

8. TPA3008

The TPA3008D2 is a 10-W (per channel) efficient, class-D audio amplifier for driving bridged-tied stereo speakers. The TPA3008D2 can drive stereo speakers as low as 8Ω. The high efficiency of the TPA3008D2 eliminates the need for external heatsinks when playing music. The gain of the amplifier is controlled by two gain select pins. The gain selections are 15.3, 21.2,

27.2 and 31.8 dB. The outputs are fully protected against shorts to GND, VCC, and output-output shorts. A fault terminal allows short-circuit fault reporting and automatic recovery. Thermal protection ensures that the maximum junction temperature is not exceeded.

Block diagram of TPA3008D2:

9. T312

Function: VSB/64QAM/256QAM demodulator, demodulate 44MHZ digital IF single into TS stream and sent to video decoder PW2000. L723 and C941make up into 44MHZ lowpass of cut-off frequency. L=330NH, C=39PF.

Wiring diagram

Backlight

Board 3

Backlight

Board 4

Left speaker – black wire

Left speaker + white wire

Power board

Backl ight c ontrol la mp

LVDS in terf ace

IR borad

Hight frequency

board

Main

Board

Button board

Backlight

board 1

board 2

Right speaker + red wire

Right speaker – black wire

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 z Bad status in signal receiving

z Poor signal

z Check if there are failures with the electrical connector or

the antenna.

z Check if the antenna is properly connected.

Fringe in picture z Check if the antenna is correctly oriented.

z 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 z Check to see if the power plug has been inserted properly

No picture and sound z 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 z Check is the screen position and size is correctly set up.

Picture is twisted and deformed z Check to see if the picture-frame ratio is properly set up.

Picture color changed or colorless z Check the “Component” or “RGB” settings of the liquid

z Possibly due to interference from automobile, train, high

voltage transmission line, neon lamp etc.

z Maybe there is interference between antenna and power

supply line. Please try to separate them in a longer

distance.

z Maybe the shielded-layer of signal wire is not connected

properly to the connector.

z 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)

z See if it’s receiving the signal that is transmitted from other

source than the station

z Check if it’s connected to the wrong terminal or if the input

mode is correct.

z Check if the signal cable connection between video

frequency source and the liquid crystal TV set is correct.

z Check if all the picture setups have been corrected.

crystal TV set and make proper adjustment according to the

signal types.

Picture too bright and there is

distortion in the brightest area

Picture is whitish or too bright in the

darkest area of the picture

No picture or signal produced from

the displayer if “XXX in search”

appears.

There appears an indication -

“outside the receivable scope)

Remote control cannot work

properly

No picture and sound, but only

hash.

Blur picture z Check if the antenna cable is correctly connected.

No sound z Check if the “mute” audio frequency setting is selected.

When playing VHS picture search

tape, there are lines at the top or

bottom of the picture.

z Check if the contrast setting is too high.

z Possibly the output quality of DVD broadcaster is set too

high.

z It maybe also due to improper terminal connection of the

video frequency signal in a certain position of the system.

z Check if the setting for the brightness is too high

z Possibly the brightness grade of DVD player (broadcaster)

is set too high.

z Check if the cable is disconnected.

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

mode is correct.

z Check if the TV set can receive input signal. The signal is

not correctly identified and VGA format is beyond the

specified scope.

z Check if the batteries are installed in the reverse order.

z Check if the battery is effective.

z Check the distance or angle from the monitor.

z Check if there is any obstruct between the remote control

and the TV set.

z Check if the remote control signal- receiving window is

exposed to strong fluorescence.

z Check if the antenna cable is correctly connected, or if it

has received the video signal correctly.

z Of if it has received the right video signal.

z Check if the sound volume is set to minimum.

z Make sure the earphone is not connected.

z Check if the cable connection is loose.

z 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

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

≥10mm ≥5mm

3. Troubleshooting guide

Yes, turn the unit on

Connect the power

A red indicator lights?

A blue indicator lights?

Yes

Does backlight light up

Yes

Check if the display of each

channel’s video signal is normal

Check if the display of each

channel’s audio signal is normal

Check Power supply, check if 50V_IN (X14 pin9)

on 55# board is normal, the voltage of X6 pin8 on

main board is normal. IR board has problem.

Check STANDBY, check if 5V_IN is normal

Check the voltage of backlight board, other voltages

and the communication of PWM2000 DDR matching

resistance

Check if the signal inputted from the channel to pin

IC is normal or IC and its periphery is normal or the

output of LVDS is normal

Check if the signal inputted from the channel to pin

IC is normal or N13 on main board, N703 on 55#

board, TPA3008D2, MSP4440 and its periphery is

normal.

3.1 No raster, no picture and no sound

No raster, no picture and no sound

Is the power indicator lights?

Is the blue indicator

hts?

Yes

Normal

Check the input voltage

Abnormal

Check STANDBY,

check if 5V_IN is

normal.

Check the output of

DC-DC on main

board

Abnormal Normal

Disconnect the power supply board

with the data processing board, and

then measure 5V_IN

Normal

Abnormal

Check if there are

short or open circuits

on correlative circuits

Normal Abnormal

Check if the voltages of

correlative circuits on high

frequency board are normal

Normal Abnormal

Check STANDBY

and 18V, if they are

short to the ground,

open circuit, or

com

onent damaged

The power supply

board fails to

work properly

Print track information from

serial port to make sure the

problem of correlative module

There are short or open

circuits on correlative

circuits

Note: The soldering quality of resistor rows between N30, N31, N32, N33 and N3 is very important, if it has problem, DDR may fail to work properly.

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

The I2C communication of EEPROM N35 made a mistake. Note: Please refer to checking procedure (5) to get the methods for checking the phenomenon of no picture but with sound of HDMI channel

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

Sound only with raster

Check if the power supply of

panel is normal or not

Normal

Abnormal

Check the signal outputted from N2

to X8 is normal or not

Check pin 5 of N26 is

18V or not

Normal

Abnormal

LVDS receiver board

has problem

Check the power supply and

the periphery circuit of N2

Yes N o

Check N26 and its

periphery circuit

3.4 No sound but with picture

Check if corresponding pins of power

amplifier have output

Yes No

Check periphery circuit

of power amplifier’s

back level

Check if there have signals

inputted from C801 and C803 to

power amplifier

Check if corresponding

channels of N705 have

input signal

Yes No

Check periphery circuit of

N705 ， crystal oscillation

and power supply

No sound but with picture

Check if X709of 55# has output

Check periphery circuit of power

amplifier, power supply circuit and

circuit of pin MUTE

Follow the direction of audio

signal input to check each

channel

Ye s

Speaker fails to work

3.5 A certain channel fails to work properly

a) AV/S-terminal with no picture

b) TV with no picture

Check the signal source

Check periphery circuit of

N37(sub) or N2(main) and

power supply circuit

Check periphery circuit of

T700(sub) or T740(main) and

power supply

Check if R713 or R714 has input

nal

Ye s No

Check if C19, C23(sub) or C272,

C271(main) have input signal

Ye s

Check each channel between

socket and N37 or N2.

Check if 55# R845(main) or R807(sub)

has output signal

Check signal

transmission circuit

Ye s

Check if C22(sub) or

C262(main) has input signal

Check N37 and its periphery

circuit, then refer to (3)

checking procedure

Note: “main” means main channel; “sub” means sub-channel.

Ye s

c) D_Sub with no picture

channe

Check the signal source

d) YPbPr with no picture

Check if the socket on main

Check the signal source

Check if R34, R35, R36

has si

nal

Ye s

Check the signal

oard has input signal

Ye s

Check if N2 has input signal

Check the channel between

the socket and N2

Check if C260 input signal

Ye s

Refer to (3) checking

rocedure

Ye s No

Check N2 and its periphery

circuit, then refer to (3)

checking procedure

e) HDMI with no picture

Check the signal source

Check N23 and its

periphery

Note: in order to display HDMI picture properly (especially when use the DVD with HDCP information),

first make sure to flash write N16 and N171G(EDID chip of HDMI) accurately.

f) Digital program can’t be received

Check if the mode is correct or

not

Ye s

Yes

Check if N22 has

signal output

Ye s

If R196 has output

Check if power supply of

T702 and N717 is normal

Ye s

Select the mode of identifiable Check if the socket has signal

Refer to (3) checking

procedure

Check N22 and its

eripheral circuit

Ye s

Check the corresponding

power supply circuit

Check if R821 has TS signal

Ye s

Check if the connection

of X711

X741 is normal

Check if C936 and C937

output 44MHZ signal

Abnormal

Check N3 and its

eripheral circuit

Normal

Change the socket

If it receives NTSC

signal normally

Yes

Check N717

peripheral circuit.

Replace T202

ATSC signal intensity is lower

than the rece

tion intensity

g) HDMI with no sound

Check if R187 3pins output square-wave, and check if G4 outputs signal normally.

3.5 Abnormal picture

a) A certain differential wire pair of LVDS of X50 (RX0+/-, RX1+/-, RX2+/-, RX3+/-) is abnormal,

which may lead to lack of color or color splash.

b) The DDR matching resistor row of N2 is rosin joint, which may lead to lack of color or color

splash.

APPENDIX-A: Main assembly

NAME NO. MAIN COMPONENT AND it’S NO.

High frequency board 667.47FE27-55 N705

N709

N717

Main board 667.3FE27-01 N37

N23

Keypad board 667.42FE32-05

IR board 667.42FE32-09

Power supply board 667.42FE17-20

Remote control 301.D42FB6-06 RC-D06

Panel 335.42022-00 V420H1-L05

MSP4440G (353.44400-20)

TPA3008D2 (353.30080-10)

T312 (353.03120-10)

TVP5147M1 (353.51470-30)

PW328 (353.03280-30)

PMW2000 (353.20000-10)

SiI9011M (353.90110-10)

603-L42FE32-10 Ver.1.1

Xoceco LC-42FE32 Schematic

Specifications and Main Features

Frequently Asked Questions

User Manual