TCL LCD20W5HE Schematic

20” LCD TV TCL LCD20W5HE

Service

TABLE OF CONTENTS

Description Page Description Page

Table Of Contents.......……..............................…........1

Revision List.…........................................……......2

Important Safety Notice.……..................……......3

1.General Specifications..............................………........4

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

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

2.2.To Use the Menu………..............................…...........7

2.3.LCD TV Description…….…..............……...............15

2.4.Interface Connector……............................…...........15

3.Precautions and Notices…............……………............16

3.1.Assembly Precaution…............………….................16

3.2.Operating Precaution…………...........................16

3.3.Storage Precaution…......………………..................16

3.4.High Voltage Warning.…..........…………................16

4.Input/Output Description……..…………… ...........17

4.1.D-SUB Connector……...…………………....….......17

4.2.Factory Preset Display Modes……………..….......18

5.Front Panel Control Knobs…....................................18

6.Repair Flow Chart…….............................................19

7.Mechanical Instructions……………................25

8.PCB Layout..………….......................................29

8.1.Main Board……….....…….................................29

8.2.Power Board…...………...................................32

8.3.Tuner Board…………........................................34

8.4.IR Board……………….......................................35

8.5.Key Board………………......................................35

8.6.Headphone Board………..................................36

9.Block Diagram………………..............................37

10.Schematic Diagram………………...............…38

10.1.Main Board.............................................38

10.2.Power Board....……....................................51

10.3.Tuner Board....……....................................52

11.Exploded View………..….......................................56

12.BOM………………………………………….............57

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 VOLTAGE.

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

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20” LCD TV TCL LCD20W5HE

Revision List

Revision Date Revision History TPV Model

A00 Sep-09-06 First Version Release E206MTNMC1TLNP

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20” LCD TV TCL LCD20W5HE

Important Safety Notice

Proper service and repair is important to the safe, reliable operation of all TCL Company Equipment. The service

procedures recommended by TCL 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. TCL 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, TCL has not

undertaken any such broad evaluation. Accordingly, a servicer who uses a service procedure or tool which is not

recommended by TCL 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, TCL Company will be referred to as TCL.

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 TCL. TCL

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 TCL LCD20W5HE

1. General Specifications

Items Specification

Screen Size 20” (51cm)

Driving system TFT-LCD Panel (CMO)

Resolution 1366×768

Display Area 444.633(H) x 249.984 (V)

Pixel Pitch 325.5um × 325.5um

LCD Panel

TV Function

Video Inputs SCART, S-Video, Composite, HDMI, Component

PC Input

Display colors 16.2 million

Contrast Ratio 1000:1 (Typical)

Brightness 500 cd/m2 (Typical)

Viewing Angle 176(H)/176(V) (CR>20)

Response Time 8ms

Lamp Type/Life 60000 hr

PAL B/G, D/K, I, L/L’ and SECAM L/L’(Multi-Europe)

TV Standard

Full Channel with Electronic PLL Tuner

Sound Systems NICAM

Video Color systems PAL/SECAM/NTSC

Signal Input Analog: D-Sub 15 pin (detachable cable)

PnP compatibility DDC 2B

Input frequency Analog: FH: 31.5KHz to 48KHz FV: 56Hz to 75Hz

Input Audio Headphone Mini-jack for stereo (3.5ø)

Speaker (built-in): 3 watt speakers x 2

Audio Output Audio Output: L / R

Other Function PIP (in PC Mode)

Table Stand Included

Wall Mount VESA 100 x 100 mm

Power

Environment

Power Supply AC100V~240V, 50/60Hz

Power Consumption < 90 W

Operating temp + 0 °C ~ + 40 °C

Storage temp - 10 °C ~ + 50 °C

Operating humidity 10% ~ 85%

Headphone Mini-jack for stereo (3.5ø)

Line Output (SCART L/R)

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20” LCD TV TCL LCD20W5HE

2. Operating Instructions

2.1. The Use Of Remote Control

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

2.2 To Use The Menus

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

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20” LCD TV TCL LCD20W5HE

2.3 LCD TV Description

The LCD TV will contain a main board, a power board, an IR board, a key board, a tuner board and a

headphone Board. The main board and power board will house the flat panel to control logic I²C bus, DDC,

brightness control logic for LCD panel, DC-DC conversion to supply the appropriate power to the whole board

and transmitting TTL level signals into LCD Module to drive the LCD display circuit.

The inverter board will drive the five CCFLs (Cold Cathode Fluorescent Tube).

The switching power board will provides the power ON/OFF to control the TV and control LED indicator for

DPMS.

The function keyboard and Remote Control will provide the OSD control signal to the Main Board.

2.4 Interface Connector

(A) Power Cord Connector.

(B) RF Signal Connector.

(C) Video / Audio Signal Connectors.

(D) PC D-sub 15 pin Connector.

(E) PC Audio Connector

(F) SCART Connector

(G) S-Video Connector

(H) Composite Connector

(I) Component Connector

(J) HDMI Connector

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20” LCD TV TCL LCD20W5HE

3. Precautions and Notices

3.1 Assembly Precaution

(1) Please do not press or scratch LCD panel surface with anything hard. And do not soil LCD panel surface

by touching with bare hands (Polarize film, surface of LCD panel is easy to be flawed)

In the LCD panel, the gap between two glass plates is kept perfectly even to maintain display

characteristic and reliability. If this panel is subject to hard pressing, the following occurs:

(a) Uniform color (b) Orientation of liquid crystal becomes disorder

(2) Please wipe out LCD panel surface with absorbent cotton or soft cloth in case of it being soiled.

(3) Please wipe out drops of adhesive like saliva and water in LCD panel surface immediately.

They might damage to cause panel surface variation and color change.

(4) Do not apply any strong mechanical shock to the LCD panel.

3.2 Operating Precaution

(1) Please be sure to unplug the power cord before remove the back-cover. (Be sure the power button is

turn-off)

(2) Please do not change variable resistance settings in MAIN-BOARD; they are adjusted to the most

suitable value. If they are changed, it might happen LUMINANCE does not satisfy the white balance

spec.

(3) Please consider that LCD backlight takes longer time to become stable of radiation characteristic in low

temperature than in room temperature.

(4) Please pay attention to displaying the same pattern for very long-time. Image might stick on LCD.

3.3 Storage Precaution

(1) When you store LCD for a long time, it is recommended to keep the temperature between -10°C -50°C

without the exposure of sunlight and to keep the humidity less than 85% RH.

(2) Please do not leave the LCD in the environment of high humidity and high temperature such as 60°C,

85%RH.

(3) Please do not leave the LCD in the environment of low temperature: below -10°C.

3.4 High Voltage Warning

The high voltage was only generated by INVERTER module on Power Board, if carelessly contacted the

transformer on this module, can cause a serious shock. (The lamp voltage after stable around 600V, with

lamp current around 8mA, and the lamp starting voltage was around 1500V, at Ta=25°C)

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20” LCD TV TCL LCD20W5HE

4. Input/Output Description

4.1 D-SUB Connector

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

1. Position 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.

2. Connect the 15-pin 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:

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6

11 15

5

10

15 - Pin Color Display Signal Cable

Pin No. Description Pin No. Description

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 H-Sync.

6 Red Ground 14 V-Sync.

7 Green Ground 15 Serial Clock for DDC

8 Blue Ground

3. Apply power to the display by turning the power switch to the "ON" position and allow about ten seconds

for Panel warm-up. The Power-On indicator lights "GREEN" when the display is on.

4. With proper signals feed to the display, a pattern or data should appear on the screen, adjust the

brightness and contrast to the most pleasing display, or press auto-adjust to get the best picture-quality.

5. This TV (with PC function) has power saving function following the VESA DPMS. Be sure to connect the

signal cable to the PC.

6. If your TV requires service, it must be returned with the power cord.

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20” LCD TV TCL LCD20W5HE

4.2 Factory Preset Display Modes:

Analog RGB Signal Timing

Horizontal Vertical Sync Polarity Presence Screen Mode

Dots × Lines

720×400 31.47 70.08

640×480 31.50 60.00

640×480 37.50 75.00

640×480 37.86 72.81

800×600 37.90 60.32

800×600 46.90 75.00

800×600 48.08 72.19

1024×768 48.40 60.00

1280×768 47.7 60

Frequency

(kHz)

Frequency

(Hz)

5. Front Panel Control Knobs

Horizontal Vertical Horizontal Vertical

Normal

(4:3)

NEG POS YES YES YES YES

NEG NEG YES YES YES YES

YES YES YES YES YES YES

FULL

(16:9)

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20” LCD TV TCL LCD20W5HE

6. Repair Flow Chart

6.1 No Power (No LED indicator)

Check power cord and board interface

OK

Check F901, BD901, D910

OK

Check IC930, Q930 (VCC1)

OK

Check Q931, ZD930 (VCC2)

OK

Check PC950, TL950 (FB)

OK

Check T901

OK

Check D970, D980

Check the load

NG

Replace F901 or BD901 or D910

Replace IC930 or Q930

Replace Q931 or ZD930

Replace PC950 or TL950

Replace T901

Replace D970 or D980

Plug in power cord and interface

OK

Check IC 960

OK

Check Q961, Q962

OK

Check Q960

OK

Check F960

NG

Replace IC 960

NG

Replace Q960

Replace F960

Check the load

Replace Q961 or Q962

OK

Check F970 (12V), F980 (24V)

NG

Replace F970 or F980

Check the load

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20” LCD TV TCL LCD20W5HE

6.2 Can not start (LED indicator yellow)

Check keyboard

NG

Repair the keyboard

Check PWR_ON signal

OK

Check 5V_SB

OK

Check 3.3V_SB

OK

Check Q940 (VCC3)

OK

Check PFC circuit

OK

NG

Return to “6.1”

Replace U703 or F702

Check Q703, Q708, Q704, Q911

NG

Replace IC901 or Q901

Check U402, U403

Check Panel inverter board

Replace Q940

NG

Check I2C communication

NG

Replace U402 or U403

NG

Replace Q703 or Q708 or Q704 or Q911

Replace panel

Check main board power supply

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20” LCD TV TCL LCD20W5HE

6.3 No Display (LED indicator green)

Check the source

OK

Check LVDS cable

NG

Reset source

Reset LVDS cable

OK

Check 24V power supply

OK

Check main board power supply

OK

Check U401

NG

Replace U401

Return to “6.1”

OK

Check I2C communication

OK

Check panel

NG

Replace panel

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20” LCD TV TCL LCD20W5HE

6.4 Abnormal Display

Check the source

OK

Check signal filter circuit

NG

Reset source

NG

Replace the filter or inductance

OK

RF signal Check TV system setup

OK

Check TU101

AV, SCART1/2_CVBS signal

S-video SCART2_Y/C signal

Check U106

OK

Check U107

Check U104

NG

Replace TU101

NG

Replace U106

Replace U107

Replace U104

PC signal

Check U102

NG

Replace U102

OK

Check U401, U407

NG

Replace U401

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20” LCD TV TCL LCD20W5HE

6.5 No sound

Check the source

OK

Check signal filter circuit

Reset source

NG

Replace the filter or inductance

Check Earphone jack

OK

NG

SIF signal Check TV system setup

Replace the Earphone jack

OK

Check TU101

NG

Replace TU101

AV, AIR1/AIR2, PC signal

Check Audio decoder MSP3410G U602

OK

Check U603

NG

Replace U603

Replace U602

Check Amplifier MAX9714 U602

OK

NG

Replace U602

Check speaker

NG

Replace speaker

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20” LCD TV

Key Board

OSD is unstable or not working

Is Key Pad Board connecting normally?

Is Button Switch normally?

Is Key Pad Board Normally?

Check Main Board

TCL LCD20W5HE

Y

N

Connect Key Pad Board

N

Replace Button Switch

Replace Key Pad Board

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20” LCD TV

TCL LCD20W5HE

7. Mechanical Instructions

Step Figure Description

Lay the

Preparation

LCD-TV on a flat, soft and clean surface.

Remove

the stand.

Remove the back cover

Remove the screws remarked on red to remove the stand.

Remove the screws marked in red to remove the back cover.

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20” LCD TV

TCL LCD20W5HE

Remove the shield.

1.Remove the screws in red marked to remove the shield.

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20” LCD TV

Remove front panel.

TCL LCD20W5HE

Remove the

screws marked in red to remove the front panel.

Remove the main board

power board and tuner board.

,

Remove the screws marked in red to remove the main board, power board and tuner board .

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