AOC N20S651 Schematic

20” LCD TV

No Brand N20S651

Service

Service

Service

Horizontal frequency 31.5 kHz to 48 kHz

TABLE OF CONTENTS

Description	Page
Table Of Contents.......…….…..............................…........1
Revision List.…….….....................................……......2
Important Safety	Notice.……..................……......3

1.Monitor Specification..…............................………........4

2.Operating Instructions……...……………….……….......5

2.1 The Use Of Remote Control..…………..................5

2.2 Front Panel Control Knobs.....................…...........7

2.3 OSD Operating…………….…............……...............8

2.4 How To Connect...………........................…............12

3.Input/Output Specification............……………............14 3.1 Input Signal Connector............………….................14 3.2 Factory Preset Display Modes........………...............14

4.Mechanical Instructions..………....……......................16

5.Repair Flow Chart…….……………………..................20

6.PCB Layout………...……….……………....….…….....26 6.1 Main Board……...……………..……………....….......26

Description

Page

6.2Power Board………………………….....….......27

6.3Key Board….….........................................…….........28

6.4Tuner Board...………...…...................................29

6.5Earphone board……………………...……..………30 7. Block Diagram..……..……................….......................31

7.1Main Board...............……..……...............................31

7.2Power Board…...……..….…...….…..........................32 8. Schematic Diagram…….….….………………….......33

8.1Main Board……...…..……….………......................33

8.2Power Board...……………….……………………...45

8.3Key Board……………..…………..………………...48

8.4Tuner Board.....…..........……………........................49

8.5IR Board...…….........…………...............................53 9. Exploded View…….........………..............…................54 10. BOM List…………………… …….....……….…..........56

SAFETY NOTICE

ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE HIMSELF WITH THE

CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING

ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFOMER FOR THIS UNIT WHEN SERVICING

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20” LCD TV				No Brand N20S651
			Revision List
	Version	Release Date	Revision History	TPV Model
	A00	Mar.-30-2006	Initial Release	E206CHNBD1GSNP

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20” LCD TV

No Brand N20S651

Important Safety Notice

Proper service and repair is important to the safe, reliable operation of all AOC Company Equipment. The service procedures recommended by AOC and described in this service manual are effective methods of performing service operations. Some of these service operations require the use of tools specially designed for the purpose. The special tools should be used when and as recommended.

It is important to note that this manual contains various CAUTIONS and NOTICES which should be carefully read in order to minimize the risk of personal injury to service personnel. The possibility exists that improper service methods may damage the equipment. It is also important to understand that these CAUTIONS and NOTICES ARE NOT EXHAUSTIVE. AOC could not possibly know, evaluate and advise the service trade of all conceivable ways in which service might be done or of the possible hazardous consequences of each way. Consequently, AOC has not undertaken any such broad evaluation. Accordingly, a servicer who uses a service procedure or tool which is not recommended by AOC must first satisfy himself thoroughly that neither his safety nor the safe operation of the equipment will be jeopardized by the service method selected.

Hereafter throughout this manual, AOC Company will be referred to as AOC.

WARNING

Use of substitute replacement parts, which do not have the same, specified safety characteristics may create shock, fire, or other hazards.

Under no circumstances should the original design be modified or altered without written permission from AOC. AOC assumes no liability, express or implied, arising out of any unauthorized modification of design.

Servicer assumes all liability.

FOR PRODUCTS CONTAINING LASER:

DANGER-Invisible laser radiation when open AVOID DIRECT EXPOSURE TO BEAM.

CAUTION-Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.

CAUTION -The use of optical instruments with this product will increase eye hazard.

TO ENSURE THE CONTINUED RELIABILITY OF THIS PRODUCT, USE ONLY ORIGINAL MANUFACTURER'S REPLACEMENT PARTS, WHICH ARE LISTED WITH THEIR PART NUMBERS IN THE PARTS LIST SECTION OF THIS SERVICE MANUAL.

Take care during handling the LCD module with backlight unit

-Must mount the module using mounting holes arranged in four corners.

-Do not press on the panel, edge of the frame strongly or electric shock as this will result in damage to the screen. -Do not scratch or press on the panel with any sharp objects, such as pencil or pen as this may result in damage to the panel.

-Protect the module from the ESD as it may damage the electronic circuit (C-MOS). -Make certain that treatment person’s body is grounded through wristband.

-Do not leave the module in high temperature and in areas of high humidity for a long time.

-Avoid contact with water as it may a short circuit within the module.

-If the surface of panel becomes dirty, please wipe it off with a soft material. (Cleaning with a dirty or rough cloth may damage the panel.)

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20” LCD TV					No Brand N20S651
1. General Specifications
		Item			Spec
		Screen Size	20” TFT-LCD Panel
		Aspect Ratio	4 : 3
		Resolution	640 x480 (XGA)
		Display Area (opening) H x V	408mm x 306mm
		Pixel Pitch	0.6375mm x 0.6375mm
	LCD Panel	Display Colors	16.2 million
		Contrast Ratio	500:1
		Brightness	450 cd/m2
		Response Time	12ms
		Viewing angel	160° H/ 160°V
		Lamp Type/Life	50000 hr
		Color Temperature	Cold / Warm/Normal
	VGA Function	Input support definition	640*480 /60Hz
		Audio input	Mini jack for stereo headphones (3.5ø)
		TV Standard	SECAM PAL
	TV Function	Color systems	SECAM L/L’ PAL BG/DK/I
		Sound System	Mono, Nicam stereo, A2
		AV	RCA x 1		Audio L/R x 1
	Video Input	S-VIDEO	S-Videox
			1
		SCART	CVBS/R
			GB
		Audio output: L / R	Speaker (built-in): Two 2 watt speakers
	Audio output
			Headphone Mini-jack for stereo (3.5ø)
	OSD Language	English France Deutsch Spanish Portugese Polish, Russian Italian Finnish
		Swedish
	Table Stand	Yes
	Wall Mount	VESA 100 x 100 mm
	Power	Power		AC100V-240V, 50/60Hz
		Power Consumption		<70W
	Panel Tilt	Forwards/Backwards/		-4°/ +18° / ± 35°
		Rotation
	Environment	Temperature		+ 0 °C ~ + 40 °C
		storage		- 25 °C ~ + 60 °C
		operating		10% ~ 85%
	Dimension	W x H x D (with stand)		498 x 495 x 185 (mm)
	Net weight	Without accessory		9.5 Kg

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20” LCD TV

No Brand N20S651

2. Operations Instructions

2.1 The Use of Remote Control

POWER:

Press to turn on/off the TV. The TV is never completely powered off unless it is physically unplugged.

CH

Press or (or

MENU ▲ or ▼ button) buttons to scroll through the channels.

VOL

Press + or – (or

MENU or button) to increase or decrease the volume.

SLEEP

With this key you can set a time period after which the TV should switch itself to standby. Press the key repeatedly to select the number of minutes. The counter runs from 0 to 120 minutes. The timer begins to count down from the number of minutes selected after the display has disappeared.

SWAP

SWAP is not available on this model.

MENU

Press this key to display or exit main menu.

Size

Size is not available on this model.

Teletext function and buttons will be described on next page.

DISPLAY

Press this key to display:

(1)the channel number when watching a TV program.

(2)the input source when watching the other video

MUTE

Temporarily interrupt the sound or restore it.

SUBPAGE

Teletext Sub-page function.

0~9 DIGIT

BUTTONS

To select a TV channel.

PRE-CH

To display the previously selected TV channel.

SOUND

To select Mono/ Stereo /Dual from TV RF input.

TV/VIDEO

Select your input source: press repeatedly to select

TV, AV, S-VIDEO or SCART mode, according to where you connected your external source.

PIP/POP PIP/POP is not available on this model.

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20” LCD TV

No Brand N20S651

TELETEXT

Teletext is an information service organized like a magazine, which is provided by some TV stations in addition to regular television broadcasting.

TELETEXT

Press TELETEXT. The Teletext screen appears.

To turn off the Teletext mode, press

TELETEXT again.

MIX

Press MIX to superimpose the teletext over a normal broadcast picture. Press again to return to Teletext mode.

SIZE

Press SIZE repeatedly to display the upper teletext part, the lower teletext part and then to return to the normal.

RED / GREEN / YELLOW / BLUE

Use the COLOURED BUTTONS to operate the Teletext screen.

INDEX

Press INDEX to return to the main index page.

SUBTITLE

Press to select the next page marked as a subtitle page and request it as the display page.

HOLD

Press HOLD to hold the Teletext page when viewing information. Press again to return to automatic page update.

REVEAL

Press REVEAL to display reveal hidden words e.g. quiz page answers. Press again to hide.

PAGE SELECTION

Page can be selected in two ways.

a.Press ▼or ▲ to increase or decrease the page number by one.

b.By entering the page number, using digit buttons 0~9.

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	20” LCD TV	No Brand N20S651
	2.2 Front Panel Control Knobs

Power Key : Press to turn on or off the TV.

MENU Key : Press to show the OSD menu and exit OSD menu at the TV.

CH Down / Up Key : Select the intended function by pressing these two keys, or switch the channels in the TV mode.

Vol + /- Key : Press to confirm your function selection and adjustment volume.

Source Key : Press to select your input source.

Lay the LCD TV with the screen down on a table, as it will be easier to connect your peripheral equipment. Please take your precautions not to damage the screen.

1:AC power input terminal

2:VGA input

3:VGA audio input

4:AC main switch

5:Headphone outlet

6:SCART signal input

7:Left video/audio track input

8:AV1 signal input

9:Right video/audio track input

10:S-Video signal input

11:TV signal input

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20” LCD TV	No Brand N20S651
2.3 OSD Operations

1.Press the MENU button to display or close main menu.

2.Use the cursor up/down to select a menu item.

3.Use the cursor left/right to enter a submenu or enable/disable the function.

4.Press the MENU button to exit the menu.

Main Menu

Press the MENU button to enter the main OSD (On Screen Display). Adjust the items including Picture Setup, Sound setup, Function Setup and TV setup. When the input source is PC/AV1/AV2 (SCART)/S-VIDEO mode, only the Sound Setup, Picture Setup and Function Setup can be selected; shown in the figure below:

When the input source is TV mode, the Sound Setup, Picture Setup, Channel select Setup, Function Setup and TV Setup can be selected; shown in the figure below:

Sound Setup (Same as in PC, TV, AV1, S-Video and AV2(SCART))

1.The range of adjusting volume, bass and treble is from 0~100.

2.Select “ON” or “OFF” in sound selection to control the sound output.

3.Bass and Treble: the easy Equalizer function, Bass can adjust the low frequency sound and Treble can adjust the high frequency sound.

4.The range of adjusting Balance is -50~+50; when adjusting from 0 to -50, the sound from the left track fades until silence; when adjusting from 0 to +50, the sound from the right track fades until silence.

5.AVL: you can set it “ON” or “OFF”.

The function is to adjust the input sound automatically. You may enable this function when you notice that the sound in the two tracks are very different, in order to prevent the bad sound effect resulting from large sound variation.

6.Select "ON" or "OFF" for Loudness: a default setting is preset, you may adjust when necessary. The following menu will appear when selecting continuously:

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20” LCD TV

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7.Preset: Designed for different types of sound output, wherein, the voice music personal and theater modes are preset; you can set Bass, Treble and Equalizer in sound output mode according to your preference.

8.Equalizer: You can select and adjust 100, 300, 1K, 3K and 8K respectively (the figures represent the sound frequency range).

9.Reset to default: Reset the sound setting to the factory default value.

Picture Setting

When the input source is in PC mode, you can select Brightness, Contrast, Position, Video noise, Sharpness, Auto Adjust, Info, Color Temp., Red, Green, Blue and Reset to default; shown in the figure below:

1.Brightness and Contrast: The range can be adjusted from 0~100.

2.Position: There are two options, Horizontal and Vertical, which can be adjusted from -50 to +50.

3.Video noise: There are two options, Phase and Clock, which can be adjusted from -50 to +50.

4.Sharpness: Select from five options of Softest, Soft, Auto, Sharp and Sharpest. You may adjust the above options according to your preference.

5.Auto Adjust: Automatically adjust PC input to the optimal screen size.

6.Info: Prompt the current size for PC input definition (only the definition that can be shown by this device).

7.	Color Temp.: There are four options of color temperature provided for users -	normal, warm, cold and Personal.
	You can select the three color temperatures of normal, warm, and cold, or manually adjust red, green or blue in
	the personal setting (you can only adjust red, green and blue in the user setting).
8.	Reset to default: It is used to reset the picture settings to the factory default mode.
When the input source is in TV/AV1/S-Video/ AV2(SCART), you can select		Brightness, Contrast, Colour,

Sharpness, Dyn. skin tone, White Tone, preset and Reset to default respectively; shown in the figure below:

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20” LCD TV

No Brand N20S651

Function Setup

When the input source is in TV, AV1 AV2 or S-Video mode, you can select Source OSD, Language, Country, ACI Timers Teletext lang./ Teletext E/W and Reset to default; shown in the figure below:

1.Current Source OSD setting: When OSD is set to ON, the left upper corner of the display will show the input source or the TV channel number; when OSD is set to OFF, the input source or the TV channel number will disappear.

2.OSD language setting: There are ten language options provided - English, France, Deutsch, Spanish, Portugese, Polish, Russian, Italian, Finnish, Swedish.

3.Timers

(1).Sleep Timer: Set the sleeping timer and the alert function which indicates the time left.

(2). Reminder timer: set the Reminder timer function which give the user a warning

4.Teletext lang. and Teletext E/W the user can set the teletext language

5.Reset: It is used to reset the OSD settings.

When the input source is in PC mode, you can select Source OSD, Language, Timers and Reset to default; shown in the figure below:

Source OSD, Language, Timers and Reset to default options are operated similarly as the above instructions! When the input source is in TV mode, you can select the difference function.

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20” LCD TV

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Country and ACI function the user can select Country and if the program system has ACI Auto Channel Installation function

TV Setting

The following menu appears only in the TV mode.

A. channel select function

This set can give the user a channel list that all channel received

B. channel setup function

1.Program nr: Shows the current program number.

2.Program name show the program name, also the user can give the program a unique name

3.Colour System / sound system: select the colour and sound system the current channel.you can selet ”auto”,the set will identify it by oneself

4.Auto search: Select "Auto Search" to search all signaled channel; when the searching is complete, it stays at the first channel with signal and all channels that have been located are stored. If you would like to stop "Auto Search" during the process, simply by pressing the function button.

5.Frequency show the current signal Frequency

6.AFC can be set to ON or OFF. When it is set to ON, the TV will search the TV signal automatically; when there is any offset in the signal, it will automatically adjust the channel to the correct position.

7.Reset to default: Reset to the factory default value.

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20” LCD TV	No Brand N20S651
2.4 How To Connect

VIDEO RECORDER

VIDEO RECORDER

1.Connect the antenna cable to the RF IN port of your VCR.

2.Connect another FR cable from the port of your VCR to the antenna port of you TV set. If you have connected the video/audio cable to the video AV port, you may have better sound and picture when playing the VCR .

If your VCR has an S-VHS video jack:

For improved picture quality, connect a S-Video cable with the S-VIDEO input on the TV.

S-Video does not provide audio, audio cables must still be connected to provide sound(AV and S terminal share one audio input).

Watching VCR

1.If you use connection TV, select the TV channel auto search.

2.If you use connection AV, select video AV input.

3.Insert videotape in the VCR and press the PLAY button.

How to connect

1.The SCART socket can be connected a VCR, a camcorder, a DVD player, a satellite receiver, a decoder or a game console form SCART cable.

2.The 21pin SCART socket can also be used as an output to Audio/Video equipment.

How to use

Scart source has the first priority. For example: when playing under other sources such as TV/AV/S-VIDEO/PC, if we input the scart signal, the TV will switch to Scart menu automatically.

How to connect

1. Connect the camera, camcorder and game set to the ports of the audio/video set.

2. The camcorder may get better picture by connecting a S-VHS cable between the S terminal and the Audio set.

How to use it

1.Select the video AV or S terminal input.

2.Enable the exterior AV equipment.

Warning: In case you notice scrolling images, wrong colors or no color, no picture or even combinations of these, on your screen, check if the connections are done in the right way. Check if the cable colors match with the Input connector colors.

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20” LCD TV

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WALL MOUNT

Use of Wall Mount Bracket:

1.Remove the hinger cover.

2.Remove the four units M4.0 screws.

3.Remove the base ass’y.

4.Fasten four units M4.0 X 10mm screws to secure the wall mount bracket.

1.The headphone jack is located at the side of the TV.

2.The MUTE key on the remote control works on both internal speaker and the headphone.

3.Use volume key to adjust the volume.

Care of the screen

Do not rub or strike the screen with anything hard as this may scratch, mar, or damage the screen permanently. Unplug the power socket before cleaning the screen. Dust the TV by wiping the screen and the cabinet with a soft, clean cloth. If the screen requires additional cleaning, use a clean, damp cloth. Do not use liquid cleaners or aerosol cleaners.

Mobile telephone warning

To avoid disturbances in picture and sound, malfunctioning of your TV or even damage to the TV, keep away your mobile telephone from the TV.

End of life directives

We are paying a lot of attention to produce environmentally friendly in green focal areas. Your new receiver contains materials which can be recycled and reused.

At the end of its life specialized companies can dismantle the discarded receiver to concentrate the reusable materials and to minimize the amount of materials to be disposed of.

Please ensure you dispose of your old receiver according to local regulations.

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20” LCD TV

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3. Input/Output Specification

3.1 Input Signal connector

This procedure gives you instructions for installing and using the LCD TV display.

Lay the display on the desired operation and plug the power cord into a convenient AC outlet. Three-wire power cord must be shielded and is provided as a safety precaution as it connects the chassis and cabinet to the electrical conduct ground. If the AC outlet in your location does not have provisions for the grounded type plug, the installer should attach the proper adapter to ensure a safe ground potential.

Connect the 15-pin D-SUB color display shielded signal cable to your signal system device and lock both screws on the connector to ensure firm grounding. The connector information is as follow:

15 - Pin Color Display Signal Cable

	1		5
	6		10
	11		15
Pin	Signal Assignment	Pin	Signal Assignment
1	Red Video	9	No Pin!
2	Green Video	10	Sync. Ground
3	Blue Video	11	Not Used
4	Not Used	12	Serial Data for DDC
5	GROUND	13	Horizontal Sync.
6	Red Video Ground	14	Vertical Sync.
7	Green Video Ground	15	Serial Clock for DDC
8	Blue Video Ground

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20” LCD TV					No Brand N20S651
3.2 Factory Preset Display Modes
	Analog RGB input signal timing
	Timing		Resolution	H/V	Remark
				frequency
	T115		640*480	31k/70Hz	can show this timing, but it is out of range actually
	T116		640*480	31K/60Hz	can show this timing.
	T117		640*480	37K/75Hz	Can not display this timing, show “out of range”
	T118		640*480	37K/72Hz	can show this timing, but it is out of range actually
	T119		640*480	43K/85Hz	Can not display this timing, show “out of range”
	T126		800*600	37.8K/60Hz	can show this timing, but it is out of range actually
	T127		800*600	46K/75Hz	Can not display this timing, show “out of range”
	T128		800*600	48K/72Hz	can show this timing, but it is out of range actually
	T129		800*600	53K/85Hz	Can not display this timing, show “out of range”
	T137		1024*768	48K/60Hz	can show this timing, but it is out of range actually
	T138		1024*768	56K/70Hz	can show this timing, but it is out of range actually
	T139		1024*768	60K/75Hz	Can not display this timing, show “out of range”
	T140		1024*768	69K/85Hz	Can not display this timing, show “out of range”
	T144		1280*1024	63K/60Hz	can show this timing, but it is out of range actually
	T148		1280*1024	80K/75Hz	Can not display this timing, show “out of range”

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	20” LCD TV		No Brand N20S651
	4. Mechanical Instructions
	Step	Figure	Description

	Preparation	Remove the
	and
		screws
	remove
		remarked in red
	the base

	Remove	Remove the
		screws
	back cover
		remarked in red

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	Remove	Remove the
		screws
	shield
		remarked in red

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Remove		Remove
the boards		connectors and
and main		the screws
frame		remarked in red

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20” LCD TV

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	Remove the
Remove	screws
the panel	remarked in red

The end

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5. Repair Flow Chart

5.1. No Display (LED indicator green)

No display

				NG
	Check the source						Reset source
	OK
				NG
	Check LVDS cable						Replace LVDS cable
	OK
					NG
	Check 12V power supply							Return to “5.3”

OK

Check main board power supply

OK

NG

Check U406 Replace U406

OK

				NG
Check I2C communication						Repair I2C communication relative circuit
	OK
			NG
	Check panel				Replace panel

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20” LCD TV			No Brand N20S651
5.2. Can’t start (LED indicator yellow)
	Can’t start

NG

Check keyboard

Repair the keyboard

OK

NG

Check 5V_SB

Check every chip power supply

OK

NG

Check I2C communication

Replace I2C communication component

OK

NG

Check oscillistor

Replace oscillistor

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20” LCD TV		No Brand N20S651
5.3. No Power (No LED indicator)
	No Power

Check power		NO
				Plug in power cord and interface
cord and board
interface
OK		NG
				Replace F901 or BD901
Check F901, BD901
		Check the load
OK

Check IC901, Q901

OK

Check T901

OK

Check D904, D905

OK

Check Q903, ZD902, IC903 IC902 and relative circuit

OK

NG

Replace IC901 or Q901

NG

Replace T901

NG

Replace D904, D905

NG

Replace Q903, ZD902, IC903 IC902

Check Q906, IC905 and relative circuit

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20” LCD TV		No Brand N20S651
5.4. Abnormal Display
	Abnormal display

NG

Check the source

Reset source

OK

NG

Check signal filter circuit

Replace the filter or inductance

OK

NG

NG

OK

AV, S-video signal

component PC signal

Check input signal

RF signal

Check TV system setup

OK

OK

OK

NG

Check LVDS cable

Replace LVDS cable

Check TU601

Repair each relative circuit

OK

NG

OK

Check panel

Replace panel

Replace TU601

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5.5. No Sound

No sound

NG

Check the source

Reset source

OK

NG

Check signal filter circuit

Replace the filter or inductance

OK

NG

Check Earphone jack

Replace the Earphone jack

NG

OK

SIF signal

Check TV system setup

OK

NG

Check TU601

Replace TU601

OK

NG

OK

AV, component, S-video, PC signal

Check relative circuit

NG

Check Amplifier TDA7266D U601

Replace U601

OK

NG

Check speakers

Replace speakers

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