SHARP LC-20C2E Service Manual

SERVICE MANUAL LCD COLOUR TELEVISION

LC-20C2E

SERVICE MANUAL

S81Y6LC-20C2E

LCD COLOUR TELEVISION

MODEL LC-20C2E

MODEL

In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified be used.

LC-20C2E

CONTENTS

Page

» IMPORTANT SERVICE SAFETY PRECAUTION ................................................................................ 2

» ELECTRICAL SPECIFICATIONS......................................................................................................... 3

» OPERATION MANUAL......................................................................................................................... 4

» OUTLINE DIMENSION FIGURE .......................................................................................................... 5

» DISASSEMBLY OF THE SET .............................................................................................................. 6

» ADJUSTING PROCEDURE OF EACH SECTION ............................................................................... 9

» TROUBLE SHOOTING TABLE ..........................................................................................................12

» CHASSIS LAYOUT............................................................................................................................. 17

» BLOCK DIAGRAMS ........................................................................................................................... 20

» DESCRIPTION OF SCHEMATIC DIAGRAM ..................................................................................... 23

» OVERALL SCHEMATIC DIAGRAM ................................................................................................... 24

» SCHEMATIC DIAGRAMS................................................................................................................... 26

» PRINTED WIRING BOARD ASSEMBLIES........................................................................................ 46

» PARTS LIST

ELECTRICAL PARTS .................................................................................................................... 50

INVERTER A UNIT................................................................................................................ ......... 50

INVERTER B UNIT ........................................................................................................................ 50

MAIN UNIT ..................................................................................................................................... 50

VIDEO UNIT................................................................................................................................... 54

SWITCH UNIT................................................................................................................................ 55

S-OUT UNIT................................................................................................................................... 55

CABINET PARTS LIST .................................................................................................................. 56

SUPPLIED ACCESSORIES PARTS.............................................................................................. 56

PACKING PARTS........................................................................................................................... 56

CABINET AND MECHANICAL PARTS.......................................................................................... 57

» PACKING OF THE SET...................................................................................................................... 58

SHARP CORPORATION

LC-20C2E

Service work should be perfomed only by qualified service technicians who are thoroughly familiar with all safety checks and the servicing guidelines which follow:

IMPORTANT SERVICE SAFETY PRECAUTION

WARNING

1. For continued safety, no modification of any circuit should be attempted.

2. Disconnect AC power before servicing.

CAUTION

FOR CONTINUED PROTECTION AGAINST A RISK OF FIRE REPLACE ONLY WITH SAME TYPE FUSE. F1 (2A, 250V), F2 (1.6A, 250V), F4 (315mA, 250V) FUSE.

BEFORE RETURNING THE RECEIVER (Fire & Shock Hazard)

Before returning the receiver to the user, perform the following safety checks:

1. Inspect all lead dress to make certain that leads are not pinched, and check that hardware is not lodged between the chassis and other metal parts in the receiver.

2. Inspect all protective devices such as non-metallic control knobs, insulation materials, cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacitor networks, mechanical insulators, etc.

3. T o be sure that no shock hazard exists, check for leakage current in the following manner.

• Plug the AC cord directly into a 110~240 volt AC outlet, and connect the DC power cable into the receiver's DC jack. (Do not use an isolation transformer for this test).

• Using two clip leads, connect a 50k ohm, 10 watt resistor paralleled by a 0.15µF capacitor in series with all exposed metal cabinet parts and a known earth ground, such as electrical conduit or electrical ground connected to earth ground.

• Use an AC voltmeter having with 5000 ohm per volt, or higher, sensitivity or measure the AC voltage drop across the resisor.

• Connect the resistor connection to all exposed metal parts having a return to the chassis (antenna, metal cabinet, screw heads, knobs and control shafts, escutcheon and etc.) and measure the AC voltage drop across the resistor. All checks must be repeated with the AC cord plug connection reversed. (If necessary, a nonpolarized adaptor plug must be used only for the purpose of completing these checks.) Any reading of 0.75V peak (this corresponds to 0.5 milliamp. peak AC.) or more is excessive and indicates a potential shock hazard which must be corrected before returning the monitor to the owner.

DVM

AC SCALE

50k ohms.

10W

0.15 µF

TEST PROBE

TO EXPOSED METAL PARTS

CONNECT TO KNOWN EARTH GROUND

234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234

SAFETY NOTICE

Many electrical and mechanical parts in LCD television have special safety-related characteristics. These characteristics are often not evident from visual inspection, nor can protection afforded by them be necessarily increased by using replacement components rated for higher voltage, wattage and etc. Replacement parts which have these special safety characteristics are identified in this manual; electrical

and shaded areas in the

Schematic Diagrams

For continued protection, replacement parts must be identical to those used in the original circuit. The use of a substitute replacement parts which do not have the same safety characteristics as the factory recommended replacement parts shown in this service manual, may create shock, fire or other hazards.

components having such features are identified by “ å”

234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234

Replacement Parts Lists

and

ELECTRICAL SPECIFICATIONS

Items .............................................................20" LCD COLOUR TV, Model: LC-20C2E

LCD panel .................................................................................. 19.7" BLACK TFT LCD

Number of pixels........................................................................................ 921,600 dots

Video colour system ........................................................................PAL/SECAM/NTSC

TV FUNCTION

TV Standard (CCIR) .......................................................................BG/L/DK, I, M, N

TV Tuning System ..................................................................... Auto preset 197 ch.

STEREO/BILINGUAL ............................................................................NICAM, IGR

AUTO PRESET ................................................................................................... Yes

CATV.....................................................................................................~Hyper Band

Brightness....................................................................................................... 430 cd/m

Lamp life ....................................................................................................60,000 hours

Viewing angles....................................................................................... H: 160° V: 160°

Audio amplifier ................................................................................................. 2.5W × 2

Speakers....................................................................................................5 cm φ 2 pcs.

Terminals

A V-IN1................................................................................................................ RGB

AV-IN2.............................................................................. S-VIDEO, VIDEO, AUDIO

OUT ................................................................................................................AUDIO

ANTENNA............................................................................................................DIN

HEADPHONES........................................................................3.5 mm φ jack (Front)

OSD language ...................... English/German/French/Spanish/Italian/Swedish/Dutch/

Power requirement .................................................. DC 13V, AC 110 - 240 V, 50/60 Hz

Power consumption ........................................................... 42W (Connected to DC13V)

Dimensions .............................................476.6mm (W) × 556.4mm (H) × 229.4mm (D)

Weight................................................................... 8.0 kg, incl. stand, excl. accessories

Accessories ........................................ R/C, Batteries, AC adaptor, Power supply cord,

Operation manual, Cable clamp

LC-20C2E

Specifications are subject to change without prior notice.

LC-20C2E

OPERATION MANUAL

Controls Terminals

Front view

To change the vertical angle of the LCD TV set, tilt the screen up to 5 degrees forward or 10 degrees backward. The TV set can also be rotated 40 degrees horizontally. Please adjust the angle so that the TV set can be watched most comfortably.

Speaker

(Left)

Control panel

Headphone

TV/VIDEO

CH ( )/( )

Volume (+)/(–)

TV/VIDEO

A green indicator lights when the power is on and a red indicator lights when in the standby mode (the indicator

Power/Standby indicator

will not light when the main power is off).

Speaker (Right)

Table stand

MAIN POWER

Remote sensor window

AV-IN 1

RGB

AUDIO OUT

POW

INPUT

DC13V

Antenna

AV-IN 1 (21-pin EuroSCART)

AUDIO OUT (L) AUDIO OUT (R) POWER INPUT DC 13 V

Rear view

AV-IN 2

S-VIDEO

VIDEO

AUDIO

Carring handle

VIDEO AUDIO (L)

AUDIO (R) S-VIDEO

Note:

TV/VIDEO, CH(

the remote control. Fundamentally, this operation manual provides a description based on operation using the remote control.

)/( ), and Volume (+)/(–) on the main unit have the same functions as the same buttons on

Remote control

(Power)

OK, Programme Table

INFO

Turns on the menu

information when

the menu is displayed.

GREEN, Sound Menu

RED, Picture Menu

TEXT

Volume (+)/(–)

Flashback

Returns to the

previous channel.

SOUND

INFO

(

RED)(GREEN)(YELLOW)(CYAN

END

MENUTEXT

)

TV/VIDEO

SOUND

Switches the sound mode.

END, Status Display

Turns on the status display when the menu is not displayed.

Upward / Downward Selection

MENU Right / Left Selection CYAN, Teletext Subtitle YELLOW, Standard Value Mute

CH ( )/( )

Channel Select

TV/VIDEO

OUTLINE DIMENSION FIGURE

476.6

379

187

401.3

556.4

403.28

298.8

300.8

LC-20C2E

56.5

0.5

295.8

296.3

369.4

110

AV-IN 1

AUDIO OUT

POWER

INPUT

DC12V

100

RGB

2815 49 66.5

S-VIDEO

3.5

AV-IN 2 VIDEO

AUDIO

100

163.9

18.5

229.4

12.5

65.5

256.9

220.4

Units: mm

LC-20C2E

DISASSEMBLY OF THE SET

1. Remove 4 screws from the stand.

2. Detatch the terminal cover.

3. Remove 5 screws from the B cabinet.

4. Remove 3 screws.

5. A cabinet is opened in order of 5-1 ~ 5-9, and B cabinet is removed.

6. Remove 4 screws and detatch the stand fixing angle.

7. Disconnect the connectors from the PWBs.

5-4

5-5

Cabinet A

5-7

5-8

5-9

Terminal Cover

5-6

5-3

Cabinet B

5-2

Stand

5-1

SC1202

P2003 P3301

SC1201

(Main PWB)

P701

P903

SC901

(Tuner Unit)

SC902

P904

P702

P703

P3601

P3604

(SWITCH PWB)

SC802

P3602

P901

P305

P3302

P4004

(S-OUT PWB)

(Inverter A PWB)

P6751P6755

(Video PWB)

P5001

P6551

P6555

P304

(Inverter B PWB)

8. Remove 2 screws from the INVERTER A PWB.

9. Remove 4 screws from the TUNER PWB.

10.Remove 2 screws from the VIDEO PWB.

11.Remove 3 screws from the MAIN PWB.

12.Remove 2 screws from the INVERTER B PWB.

13.Remove 2 screws form the LCD panel.

14.Remove 2 screws from the S-OUT PWB.

LC-20C2E

Inverter A PWB

Tuner Unit

Main PWB

21pin Terminal Fixing Angle

Video PWB

Inverter B PWB

Chassis Frame

LCD Panel

A Cabinet

Switch PWB

LC-20C2E

• Precautions in handling the LCD panels.

1. Work in a clean room. (with humidities below 50%)

2. Be sure to wear an anti-static armband.

3. Handle the panels on an electroconductive mat.

4. Be careful not to fall, shake and shock the panels.

5. Use an ionizer. (within 30cm)

15.Remove 8 screws from the LCD unit and detach the shielding plate.

16.Remove 2 reflevction sheets.

17.Remove the fluorescent lamp.

18.Remove the light guide.

19.Remove the spacer.

20.Remove the diffusion sheet, prizm sheet and D-BEFE.

21.Remove the LCD Panel.

LCD Panel

Source-FFC

Fluorescent Lamp

Light Guide

GATE-FFC

Spacer

Prizm Sheet

D-BEFE

Diffusion Sheet

Fluorescent Lamp

Spacer

Shielding Plate

Reflection Sheet 2

Reflection Sheet 1

LC-20C2E

ADJUSTING PROCEDURE OF EACH SECTION

[1] Entering the MAIN side adjustment process mode

There are three methods below.

1) Press the “Adjustment process key” on the remote control after turning on the power.

2) Pressing both the MENU key and the TV/VIDEO key on the main body, turn on the power. Then, press the volume DOWN key and the tuning DOWN key at the same time.

3) Turn on the power with falling either KEY4 (pin 81 of microcomputer) or KEY5 (pin 82 of microcomputer) to “L”.

[Note] For the method 3), the ROM is initialized at the same time. Therefore, 3) must be executed if IC2004 or

IC2001 is changed. For 1) or 2), the main body only enters the MAIN side adjustment process.

[2] Entering the TUNER side adjustment process mode

4) Entering the TUNER side adjustment process

MENU key on the main body → Cursor UP key (remote control) → Select the position shown in the figure below and press the M key (remote control) within 1 second. → Enters the adjustment process.

Direct control at TV

Black level Contrast Colour

: select

M: Back E: End

[3] Adjustment

MAIN side adjustment (Press the “M” key to move the cursor and press the volume UP/DOWN key to make an adjustment.)

• Power supply voltage adjustment (+B 5V)

• Model setting

• Inch size setting

• COMMON BIAS adjustment of LCD module

• CUTOFF adjustment

TUNER side adjustment (Press the tuning UP/DOWN key to move the cursor and press the volume UP/DOWN key to make an adjustment.)

• Horizontal size adjustment (LCD adjustments)

• Video adjustment (other adjustments)

Y delay Subcontrast Subcolour Subbrightness Tint offset AGC gain start The TUNER side adjustment is possible. However, it is recommended to replace EAROM (I2).

LC-20C2E

3-1. +B adjustment

PAL/PAL60 SECAM NTSC

y delay 7 6

AV1 tint offset 1 1 1 AV2 sub contrast 0 2 0

AVS

AGC gain start 23

Page 9 of MAIN side adjustment process +B-ADJ Adjust the voltage of the pin 13 of P2002 to 5.0V±0.05V.

tint offset 0 0 sub contrast 2 2 sub colour 25 25 y delay 7 5 4

sub colour 30 30 20 y delay 7 5 1 tint offset 1 1 1 sub contrast 0 0 0 sub colour 30 30 30

3-2. Model setting

Page 9 of MAIN side adjustment process MODEL Set to C2E.

3-3. Inch size setting

Page 9 of MAIN side adjustment process INCH SIZE Set to 20.

3-4. COMMON BIAS adjustment of LCD module

Page 9 of MAIN side adjustment process COM BIAS Input the picture of gray scale and adjust it so as to obtain the best contrast.

3-5. CUTOFF adjustment

Page 9 of MAIN side adjustment process R CUTOFF, B CUTOFF Adjust it so as to obtain the optimal colour balance.

[4] Lamp error detection

4-1. Functional description

This LCD colour television has a function (lamp error detection) to be turned OFF automatically for safety when the lamp or lamp circuit is abnormal. If the lamp or lamp circuit is abnormal, or some other errors happen, and the lamp error detection is executed, the followings occur. 1 The main unit of television is turned OFF 5 seconds after it is turned ON. (The power LED on the front side

of TV turns from green to red.)

2 If the situation 1 happens 5 times sequentially , television can not be turned ON. (The power LED remains

red.)

4-2. Countermeasures 4-2-1. Check when turning OFF the lamp error detection

When television is turned OFF by the lamp error detection mentioned above, it enters the adjustment process with the power LED red. Entering the adjustment process turns OFF the error detection and turns ON TV. This enables the operation check to detect errors in the lamp or lamp circuit. Check whether "ERROR NO RESET" on line 7, page 1 of the adjustment process is 1 or more. If it is 1 or more, it indicates the lamp error detection was executed.

4-2-2. Resetting of the lamp error count

After confirming that the lamp or lamp circuit is normal, reset the lamp error count. Select "ERROR NO RESET" on line 5, page 1 of the adjustment process and set the number to 0 using the volume button.

LC-20C2E

Page 1 of the adjustment process

+ B – A D J 160 M O D E L C2E I NCH I S I ZE 20 N T S C P W M F R Q 0C0 ERROR NORESET 5 P M U T E OFF

Reset 0

C 2 E V E R 1 . 0 0

Afterwards, perform the operation check to confirm that the lamp error detection does not function.

LC-20C2E

No picture, No sound

Check all the settings microprocessor's adjust process menu.

Do F2, F3, F4 and F5

function?

Are T701's secondary

outputs, +38V, +16V, +9V,

+5V and -8V normal?

Remove F2, F3, F4 and F5

and check the load side.

Is there short-circuiting?

Is there short-circuiting of

T701 primary side periphery,

Q751, Q753 and P901.

Replace F2, F3, F4 and F5.

Check P901 and

connection cable.

Is T701's primary oscillator

waveform normal?

Check T701's secondary

load.

Yes Yes

No No

Yes

Fluorecent lamp failure to light up

Does F1 function?

Is the pin 34 of IC1201 in

the "H" state?

Is the Q3603 short-circuiting?

Is there short-circuiting of

T5701 and T5702 primary

side periphery, Q751~Q753.

Yes

Replace the fluorecent lamp

with new one and check

again.

Yes

Check the OFL1 line, IC1201

and their peripheral parts.

Check Q3603 and their

peripheral parts.

Check T5701, T5702,

Q5701~Q5703 and

connection cable.

TROUBLE SHOOTING TABLE

TROUBLE SHOOTING TABLE (Continued)

No picture

Check all the settings microprocessor's adjust process menu.

Is in/output of

IC801 normal?

Is in/output of

IC1201 normal?

Check IC801

and its

peripheral parts.

Check IC1201

and its

peripheral parts.

Check IC402

and its

peripheral parts.

Check IC801,

AV1 line and its

peripheral parts.

Check LCD

panel voltages

and waveform.

Yes

No picture

at all

Is in/output of

IC402 normal?

Is input at pin

73 of IC801

normal?

Yes

No TV and

VIDEO 1

output

Is voltages at

pin 3 of W7 and

pins 3, 4, 5 of

W14 tuner

normal?

Is output at pin

2 of W7 tuner

normal?

Check the

power line.

Check tuner

and its

peripheral parts.

Is input at pin

3 of IC402

normal?

Is the pins 2

and 4 of IC402

at "H" and "L"

state?

Yes

No TV output

Is the pins 65

and 66 of

IC2001 at "H"

and "L" state?

Yes

Check the its

line.

Check the its

line.

Check IC402

and its

peripheral parts.

Is input at pin

1 of IC402

normal?

Is the pins 2

and 4 of IC402

at "L" state?

Check the its

line.

Check the its

line.

Check IC402

and its

peripheral parts.

Is the pins 65

and 66 of IC2001

at "L" state?

Yes

No VIDEO 1

output

LC-20C2E

No picture

Check all the settings microprocessor's adjust process menu.

Is input at pin

74 of IC801

normal?

Check the AV2

line and their

peripheral parts.

Check the W9,

SY-line, SC-line

and their

peripheral parts.

No VIDEO 2

output

Is input at pins

71 and 72 of

IC801 normal?

No S-VIDEO

output

Is input at pin

70 of IC801

normal?

Check the

V2VO line and

their

peripheral parts.

No line

output

Is input at pins

1, 2, 3, 56, 57

and 79 of IC801

normal?

Is output at pins

11, 13 and 16

of I4 normal?

Check IC801

and their

peripheral parts.

Check I13 and

their

peripheral parts.

Check I9 and

their

peripheral parts.

Check I4 and

their

peripheral parts.

Is output at pins

11, 13 and 16

of I13 normal?

Yes

No TELETEX

output

Is output at pins

44~49 of I9

normal?

Yes

TROUBLE SHOOTING TABLE (Continued)

No picture

Check all the settings microprocessor's adjust process menu.

Is source GND

normal?

Is CSCOM

waveform

normal?

Check R1212

and their

peripheral parts.

Check IC1109,

Q1101, Q1102,

D1101, R1120,

R1130 and their

peripheral parts.

Check R1231

and their

peripheral parts.

Yes

Becomes

dark

Time passes,

becomes

dark

Is gate GND

normal?

Is gate clock

(GCK) normal?

Check R1223

and gate aray

peripheral parts.

Yes

Check D1201

and their

peripheral parts.

Is B-5.5V being

outputted?

Is VCC being

outputted?

Check T701's

secondary +5V

outputs line?

Yes

Is GSP

waveform

normal?

Check R1223

and their

peripheral parts.

Yes

Becomes

white.

Is 3.3V VHS

being

outputted?

Is source clock

normal?

Check +3.3V

outputs line of

IC752.

Check R1210,

R1211 and their

peripheral parts.

Check FB1203

and gate aray

peripheral parts.

Is output of LBR

and HG

normal?

Yes

Vertical line

output

No picture

Check all the settings microprocessor's adjust process menu.

Is output of

R0~R5

normal?

Is output of

G0~G5

normal?

Is output of

B0~B5

normal?

Check R1202,

R1203 and their

peripheral parts.

Check R1204,

R1205 and their

peripheral parts.

Check R1206,

R1207 and their

peripheral parts.

Check T701's

secondary +5V

outputs line.

Yes

Colour is

unusual

Is VLS 5V

being

outputted?

Picture

image is

gloomy

Is in/output of

SPIO and

SPOI normal?

Check R1209

and their

peripheral parts.

No picture

image

inversion

Is output V0,

V16, V32, V48

and V63

normal?

Check IC1106,

IC1107, IC1108

and their

peripheral parts.

Gradation

defect

Is output of U/D

normal?

Check Q1201

and their

peripheral parts.

Yes

LC-20C2E

+ 35 hidden pages