SHARP LC-20A2E Service Manual

SERVICE MANUAL LCD COLOUR TELEVISION

LC-20A2E

SERVICE MANUAL

S11O1LC-20A2E

LCD COLOUR TELEVISION

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

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

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

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

» REMOVING OF MAJOR PARTS .......................................................................................................... 6

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

» TROUBLE SHOOTING TABLE ........................................................................................................... 11

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

MODEL LC-20A2E

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

» DESCRIPTION OF SCHEMATIC DIAGRAM ..................................................................................... 24

» SCHEMATIC DIAGRAMS................................................................................................................... 25

» PRINTED WIRING BOARD ASSEMBLIES........................................................................................ 42

» PARTS LIST

» PACKING OF THE SET ...................................................................................................................... 55

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-20A2E

CONTENTS

ELECTRICAL PARTS..................................................................................................................... 47

MAIN UNIT ..................................................................................................................................... 47

SUB UNIT....................................................................................................................... ................ 50

INVERTER UNIT............................................................................................................................ 52

SWITCH UNIT................................................................................................................................ 52

SUPPLIED ACCESSORIES PARTS.............................................................................................. 53

PACKING PARTS ........................................................................................................................... 53

CABINET PARTS LIST................................................................................................................... 53

CABINET AND MECHANICAL PARTS.......................................................................................... 54

Page

SHARP CORPORATION

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 UP 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 initializ ed at the same time . Theref ore, 3) m ust 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 → Tuning 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

LC-20A2E

Brightness 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 ke y to mo v e the cursor and press the v olume 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-20A2E

PAL/PAL60 SECAM NTSC

y delay 7 6 0

AV1/ tint offset 1 1 1

AV2 sub contrast 0 2 0

AVS

AGC gain start 27

3-1. +B adjustment

Page 9 of MAIN side adjustment process +B-ADJ Adjust the voltage of the pin 12 of SC901 the SUB PWB to 5.0V±0.05V.

tint offset 0 0 0 sub contrast 2 2 0 sub colour 25 25 0 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 A2E.

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.

TROUBLE SHOOTING TABLE

No picture, No sound

Check all the settings microprocessor's adjust process menu.

Do F2, F3 and F4

function?

Are T701's secondary

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

+5V and -8V normal?

Remove F2, F3 and F4

and check the load side.

Is there short-circuiting?

Is there short-circuiting of

T701 primary side periphery,

Q751, Q753 and S4701.

Replace F2, F3 and F4.

Check S4701 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

T7751~7756 primary side

periphery, Q7751~Q7755.

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 T7751~T7756,

Q7751~Q7755 and

connection cable.

LC-20A2E

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

TROUBLE SHOOTING TABLE (Continued)

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

SC2001,

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

LC-20A2E

No picture

Check all the settings microprocessor's adjust process menu.

Is source GND

normal?

Is CSCOM

waveform

normal?

Check R1212,

FB1201 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?

Is output at pin

3 of IC1205

normal?

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 gate aray

peripheral parts.

Yes

Check R1223

and their

peripheral parts.

Becomes

white.

Is 3.3V VHS

being

outputted?

Is source clock

(CK) 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

TROUBLE SHOOTING TABLE (Continued)

No sound

Check all the settins microprocessor's adjust process menu.

Is the pin 53 of

IC2001 in the

"L" state?

Is output at pins

26 and 27 of

IC901 normal?

Is output at pins

1 and 7 of

IC903 normal?

Yes

No sound

from front

speakers

Is output at pins

3 and 5 of

IC303 normal?

Yes

Is output at pins

8 and 12 of

IC3305 normal?

Yes

Muting effect is

on. Check the

FSMUTE line.

Check IC901

and their

peripheral parts.

Check IC903

and their

peripheral parts.

Check IC303

and their

peripheral parts.

Check IC3305

and their

peripheral parts.

Check front

speaker and

connection

cable.

Yes

Is the pin 53 of

IC2001 in the

"L" state?

Is output at pins

24 and 25 of

IC901 normal?

Is output at pins

1 and 7 of

IC304 normal?

Yes

Is output at pins

42 and 43 of

SC402 normal?

Yes

Is output at pins

6 and 7 of

P4004 normal?

Yes

Muting effect is

on. Check the

FSMUTE line.

Check IC901

and their

peripheral parts.

Check IC304

and their

peripheral parts.

Check SC402,

SC901 and their

peripheral parts

and connection.

Check P4004

and their

peripheral parts

and connection

cable.

Yes

Check the

J4001 line.

No sound

from

headphone

Is output at pins

36 and 37 of

IC901 normal?

Is output at pins

1 and 7 of

IC902 normal?

Check IC901

and their

peripheral parts.

Check IC902

and their

peripheral parts.

Yes

No sound

from output

line

TV sound

failure

Is output at pins

15 and 16 of

SC402 normal?

Is output at pins

17 and 18 of

W9 normal?

Check SC402,

SC901 and their

peripheral parts

and connection.

Check W9 and

their peripheral

parts and

connection.

Yes

Check the

U1 line.

Yes

Is output at pin

1 of W7 tuner

normal?

Is input at pin

67 of IC901

normal?

Check the tuner

and their

peripheral parts.

Check IC901,

MONOS/SIF

line and their

peripheral parts.

Yes

LC-20A2E

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