SHARP LC20M4U Service Manual

SERVICE MANUAL

SY1E1LC-20M4U

LCD AV MONITOR

LC-20M4U

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-20M4U

CONTENTS

Page

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

» SPECIFICATIONS ................................................................................................................................ 4

» OPERATION MANUAL ......................................................................................................................... 5

» DIMENSIONS ....................................................................................................................................... 6

» REMOVING OF MAJOR PARTS .......................................................................................................... 7

» ADJUSTING PROCEDURE OF EACH SECTION ............................................................................. 10

» TROUBLE SHOOTING TABLE........................................................................................................... 13

» CHASSIS LAYOUT ............................................................................................................................. 18

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

» DESCRIPTION OF SCHEMATIC DIAGRAM ..................................................................................... 22

» SCHEMATIC DIAGRAMS ................................................................................................................... 23

» PRINTED WIRING BOARD ASSEMBLIES........................................................................................ 45

» PARTS LIST

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

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

JACK UNIT..................................................................................................................................... 56

INVERTER UNIT............................................................................................................................ 57

SWITCH UNIT................................................................................................................................ 57

CABINET PARTS LIST................................................................................................................... 59

SUPPLIED ACCESSORIES PARTS.............................................................................................. 59

PACKING PA RTS ........................................................................................................................... 59

CABINET AND MECHANICAL PARTS.......................................................................................... 60

» PACKING OF THE SET ...................................................................................................................... 62

SHARP CORPORATION

This document has been published to be used for after sales service only. The contents are subject to change without notice.

LC-20M4U

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Service work should be perfomed only b y qualified service technicians who are thoroughl y 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.

A V

F701 (1.25A, 250V), F702 (1.25A, 250V), F4701 (2.0A, 250V), F4702 (2.0A, 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 and etc.

3. To 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 A C 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 an earth ground.

• Use an AC voltmeter ha ving 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 necessar y, 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 A C .) or more is e xcessive 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

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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”

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Replacement Parts Lists

and

PRECAUTIONS A PRENDRE LORS DE LA REPARATION

Ne peut effectuer la réparation qu’ un tec hnicien spécialisé qui s’est parfaitement accoutumé à toute vérification de sécurité et aux conseils suivants.

LC-20M4U

AVERTISSEMENT

1. N’entreprendre aucune modification de tout circuit. C’est dangereux.

2. Débrancher le récepteur avant toute réparation.

PRECAUTION

POUR LA PROTECTION CONTINUE CONTRE LES RISQUES D’INCENDIE, REMPLACER LE FUSIBLE PAR UN FUSIBLE DE MEME TYPE F701 (1.25A, 250V), F702 (1.25A, 250V), F4701 (2.0A, 250V), F4702 (2.0A, 250V).

A V

VERIFICATIONS CONTRE L’INCEN-DIE ET LE CHOC ELECTRIQUE

• Utiliser un voltmètre CA d’une sensibilité d’au moins 5000Ω/V pour mesurer la chute de tension en travers de la résistance.

• Toucher avec la sonde d’essai les piéces métalliques exposées qui présentent une voie de retour au châssis (antenne, coffret métallique, tête des vis, arbres de commande et des boutons, écusson, etc.) et mesure la chute de tension CA en-travers de la résistance. T outes les vérifications doiv ent être refaites aprés a voir inversé la fiche du cordon d’alimentation. (Si nécessaire, une prise d’adpatation non polarisée peut être utilisée dans le but de terminer ces vérifications.) Une valeur de 0.75V RMS ou plus (correspond à

0.5mA C.A.) est excessive et implique un danger de secousse électrique, qui devra être supprimé avant de retourner l'appareil à l'utilisateur.

Avant de rendre le récepteur à l’utilisateur, effectuer les vérifications suivantes.

1. Inspecter tous les faisceaux de câbles pour s’assurer que les fils ne soient pas pincés ou qu’un outil ne soit pas placé entre le châssis et les autres pièces métalliques du récepteur.

2. Inspecter tous les dispositifs de protection comme les boutons de commande non-métalliques, les isolants, le dos du coffret, les couvercles ou blindages de réglage et de compartiment, les réseaux de résistancecapacité, les isolateurs mécaniques, etc.

VTVM

ECHELLE CA

50K OHMS

10W

3. S’assurer qu’il n’y ait pas de danger d’électrocution en vérifiant la fuite de courant, de la facon suivante:

• Brancher le cordon d’alimentation dans la prise CA de 110~240V et le câble d’alimentation CC dans le jack du moniteur. (Ne pas utiliser un transformateur pour

0.15 µF

SONDE D'ESSAI

cet essai.)

• A l’aide de deux fils à pinces, brancher une résistance de 1,5kΩ 10 watts en paralléle avec un condensateur de 0,15µF en série avec toutes les pièces métalliques exposées du coffret et une terre connue comme une conduite électrique ou une prise de terre branchée à

VERS PIECES METALLIQUES EXPOSEES

CANNECTER A UNE MASSE DE TERRE CONNUE

la terre.

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AVIS POUR LA SECURITE

De nombreuses pièces, électriques et mécaniques, dans les téléviseurs présentent des caractéristiques spéciales relatives à la sécurité, qui ne sont souvent pas évidentes à vue. Le degré de protection ne peut pas être nécessairement augmentée en utilisant des pièces de remplacement étalonnées pour haute tension, puissance, etc. Les pièces de remplacement qui présentent ces caractéristiques sont identifiées dans ce manuel; les pièces électriques qui présentent ces particularités sont

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identifiées par la marque “ å” et hachurées dans

des pièces de remplacement et les diagrammes schématiques.

Pour assurer la protection, ces pièces doivent être identiques à celles utilisées dans le circuit d’origine. L’utilisation de pièces qui n’ont pas les mêmes caractéristiques que les pièces recommandées par l’usine, indiquées dans ce manuel, peut provoquer des électrocutions, incendies, radiations X ou autres accidents.

la liste

LC-20M4U

SPECIFICATIONS

Items .......................................................... 20" LCD AV MONITOR, Model: LC-20M4U

LCD panel..................................................................................... 20" BLACK TFT LCD

Number of dots .................................................................921,600 (640 x 3 x 480) dots

Low reflection.................................................................................................. Non-glare

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

Viewing angles

Left to right......................................................................................................... 160°

Upper to lower ................................................................................................... 160°

Lamp life ....................................................................... 40,000 hours (at normal mode)

Video color system ..............................N358/N443/PAL/PAL-M/PAL-N/PAL-60/SECAM

Audio amplifier ...................................................................... 4.0 W (0.7 W x 2 + 2.6 W)

Speakers

Full range.......................................................... 1.2 x 1.6 in. (3 x 4 cm) Oval, 2 pcs.

Woofer ............................................................................. 3.1 in.(8 cm) Round, 1 pc.

Terminals

AV 1 IN........................................ Video Composite (BNC type), S-video, Audio R/L

AV 2 IN/OUT ............................................. Video Composite (BNC type), Audio R/L

Headphone jack..................................................................... 0.1 in. (3.5 mm) φ jack

Power supply

DC operation...................................................... DC 13 V, Typical: 3.0 A, Max: 3.8 A

AC operation...........................................AC 110 - 240 V, 50/60 Hz with AC adapter

Power consumption ....................................AC 120V, Typical; 50 W, Standby: 0.5 W

Appearance

Exterior color .................................................................................................... Silver

Outside dimensions ................................................ 18.1 (W) x 17.2 (H) x 7.3 (D) in.

Net weight........................................ 19.0 lbs (8.6 kg), incl. stand, excl. accessories

Accessories

Operation manual ...........................................................Language: English/French/

Remote control ....................................................................... Infrared wireless type

AC adapter.......................................................................... Multi-Voltage type, 1 pc.

AC cord..................................................................................... 6.1 ft (1.85 m), 1 pc.

Batteries............................................. "AAA" size (UM/SUM-4) Dry Battery x 2 pcs.

Cable clamp..................................................................................................... 2 pcs.

OSD language ..........................................................................English/French/Spanish

Component input, Y/PB/PR (BNC type)

460 (W) x 437.5 (H) x 186 (D) mm

13.4 lbs (6.1 kg), excl. stand

Spanish/Portuguese

(Infrared carrier frequency: 38 kHz)

DC cable: 6.5 ft (2 m)

DC power converter: 2.6 (W) x 1.5 (H) x 5.5 (D) in.

(67 (W) x 37 (H) x 140 (D) mm)

Specifications are subject to change without prior notice.

OPERATION MANUAL

LC-20M4U

Main unit (front view)

Main unit (rear view)

Remote Control

LC-20M4U

DIMENSIONS

(Unit: inch/mm)

REMOVING OF MAJOR PARTS

1. Detach the Rear cover.

2. Remove the Table stand fixing screws (4 pcs.).

3. Remove the Jack PWB fixing screws (9 pcs.) .

4. Remove the Cabinet B fixing screws (5 pcs.).

5. Push on the hook5-1of the Cabinet B to detach, open the cabinet and detach the hooks from

5-2

〜

5-9

, and then detach the Cabinet B.

6. Peel off the 9 wire holders and 8 tapes, then detach the connecting cords.

7. Detach the connectors from each PWB.

Cabinet B

5-4

5-5

5-6

5-3

5-2

Rear Cover

LC-20M4U

Jack PWB Holder

Tape

Cabinet A

5-7

5-8

5-9

5-1

Stand Cover

Table Stand (Cover)

Hinge Cover

Table Stand

Speaker

SC1201

SC1202

P1701

P1702

P1771

P2003

P701

(Main PWB)

SC401

(Inverter PWB)

P1703

P1702

P1701

Tape

Speaker Cover (R)

SC4402

P4602

(Switch PWB)

Tape

P4001

P4302

P4702

P4601

Speaker Cover (L)

LC-20M4U

8. Remove the Main PWB fixing screws (4 pcs.).

9. Remove the Inverter PWB fixing screws (3 pcs.).

10. Remove the Jack PWB fixing screw (1 pc.) and Ground fixing screw (1 pc.),

11. Remove the LCD unit fixing screws (2 pcs.).

12. Remove the Switch PWB fixing screws (3 pcs.).

and then remove the Reinforcement plate.

Main PWB

LCD unit

Inverter PWB

Jack PWB Ass'y

P3203

Reinforcement plate

P3204

Gasket

Switch PWB

Cabinet A

» Precautions in handling the LCD panels

Fluorescent lamp (Upper) (KLMP-0133CEZZ)

Refrection Mirror (Upper) (PSHEP0223CEZZ)

LCD unit (RLCDT0060CEZZ)

Fluorescent lamp (Lower) (KLMP-0134CEZZ)

Refrection Mirror (Lower) (PSHEP0224CEZZ)

Diffusion sheet (PSHEP0179CEZZ)

Light guide plate (PGiDM0058CEZZ)

Reflection polarizing sheet (PSHEP0216CEZZ)

Reflection sheet-2 (PSHEP0187CEZZ)

Reflection sheet-1 (PSHEP0186CEZZ)

Shielding plate (PSLDM4712CEFW)

LCD unit (Front surface)

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 electro-conductive mat.

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

13. Remove the LCD unit fixing screws (4 pcs.) and the Rear surface fixing screws (3 pcs.), and then detach the Shielding plate.

14. Detach the 2 Reflection sheets .

15. Detach the upper and lower Fluorescent lamps.

16. Detach the Light guide plate.

17. Detach the upper and lower Reflection mirrors.

18. Detach the Diffusion sheet and the Reflection polarising sheet.

LC-20M4U

ADJUSTING PROCEDURE OF EACH SECTION

When the microprocessor (IC2001) or the E2PROM (IC2004) has been replaced or when the E2PROM has been initialized, it is necessary to readjust the microprocessor. Below discussed is the adjustment procedure.

Preparations

Use a dedicated AC adapter or a regulated DC power supply. AC adapter :UADP-0220CEZZ DC power supply :13 V, 3.8 A Use also a SHARP TV remote controller.

1. Adjustment procedure

Power on (initialization) → Adjustment process mode (remote controller) → +B adjustment → Counter bias adjustment → White balance adjustment → Performance check → Factory settings

Calling the adjustment process mode

There are the following two ways to enter this mode.

● Turn on the power and press the “ADJUST PROCESS” key on the remote controller.

● While holding either KEY4 (pin (81) of the microprocessor) or KEY5 (pin (82) of the microprocessor) at the “L” le v el,

turn on the power.

Using the keys for the adjustment process

Selecting an adjustment item and adjusting its setting

● Using the menu button (M key), select an item, and using the VOL+/- buttons, adjust its setting. (The menu button

serves as a toggle switch. New settings entered with the VOL buttons are made effective immediately.)

Other key-in behaviors

● The input select key serves also as a toggle switch.

The input is switched from AV1 to AV2.

● Press the auto preset button on the remote controller in the adjustment process mode, and the top item of the next

page will show up regardless of which item appears now.

Page 1 → Page 2 → ...... →Page 6 → Page 1

● Press the manual memory button on the remote controller in the adjustment process mode, and the top item of the

same page will show up.

1-1. Initialization

Ground the pins (81) and (82) of IC2001 (microprossor) and turn on the power. The unit will be initialized and then enter the adjustment process mode. Select M4U in the MODEL item. Adjustment process page 1. Select 20 in the INCH SIZE item. Adjustment process page 1. Turn off the power and get the pins (81) and (82) of IC2001 (microprossor) back to their original state.

* Before turning off the power, quit the adjustment process mode with the remote controller. If unavoidably the power must be switched off directly, wait at least 5 seconds after making the settings.

1-2. +B adjustment

Feed the standard NTSC color bar signal. Enter the adjustment process mode. Adjust the “+B-ADJ” setting on the adjustment process page 1 so that the voltage at pin (5) of P2001 should be

5.00 ± 0.02 V. Note: Mak e the 5.0V adjustment as exactly as possible because this voltage this voltage will be reference le v el f or all

the supply voltages.

1-3. Counter bias adjustment

Keep off the video input signal. Place the specified tool at the center of the screen. Observe the output of the tool on the oscilloscope screen. Adjust the “COM BIAS” setting on the adjustment process page 2 so that the peak-to-peak level of the waveform should be minimum.

1-4. White balance adjustment

Feed the NTSC monoscope pattern signal. Adjust the “RCUTOFF” and “BCUTOFF” settings on the adjustment process page 2 so as to obtain the color of the same level as the standard monitor.

Note: F or the “RCUTOFF” and “BCUT OFF” settings, keep the readings in the range of -9 to +9. If out of this r ange, the

user-adjustable range is reduced.

Adjust them in the indication value range of -9, -7, -5, -3, -1, +1, +3, +5, +7, +9 (odd numbers). When it becomes

even-numbered value (include 0), side favor noise sometimes occurs in the monochrome signal of the specific gradation.

Do not change the “GCUT OFF” settings (It also change the black level).

1-5. Factory setting

Set the product’s input mode, picture quality and other factors to their factory setting. There are the following two ways.

● With the keys of the set

In the inspection process mode, hold down both the “SELECT(▲)” and “VOL (+)” buttons of the set until “SETTING COMPLETE” appears on the screen.

Note: Be careful not to turn off the power, release the above two keys and press any other keys until “SETTING

COMPLETE” appears on the screen.

LC-20M4U

Changing on-screen display

→

Inspection process mode Factory setting Setting complete

● With the adjustment remote controller

With the adjustment remote controller, make the factory settings. Either of the following remote controllers codes will do.

→

SETTING COMPLETE

Key name Remote controller code Factory setting 100000111111110 Factory setting 100000001010110

Calling the Inspection process mode

There are the following two ways.

● With the keys of the set

Hold down the “MENU” and “AV INPUT” buttons of the set and turn on the power.

● With the adjustment remote controller

Use the inspection process key.

LC-20M4U

2. Lamp error detection

Function

For added safety, this LCD color TV set has the lamp error detection. The power is automatically turned off if the lamp or its circuit gets in trouble. If by any chance there is a problem with the lamp or its circuit, or if the lamp error detection function is activated for any other reason, the set behaves itself as follows.

1 Even when you switch on the power, the set turns itself off in about 5 seconds. (The power LED indicator on the

front of the set turns from green to red.)

2 If the above action 1 occurs 5 times consecutively, the set cannot be switched on. (The power LED indicator stays

in red.)

Correction

● Checking with the lamp error detection circuit off

If the lamp error detection fuction is activated to turn off the power LED indicator turns red and the set is now in the adjustment process mode. In this state, the error detection circuit gets disabled and the pow er is turned on again. In so doing, the lamp and its circuit can be checked for anything unusual. Check to see if “1” or higher value appears in the “ERROR NO RESET” box in the 9th line of the adjustment process page 1. If so, a lamp error has been detected.

● Resetting the lamp error counter

Finally make sure the lamp and its circuit are error-free, and reset the lamp error counter. To do so, select the “ERROR NO RESET” box in the 9th line of the adjustment process page 1 and enter “0” with the VOL button. Do the performance check and make sure the lamp error detection functions is not activated.

3. Precautions in making adjustments

In making adjustments, keep the following points in mind.

● When you have modified the MODEL and INCH SIZE settings on the process page 1, never turn off the power in

at least 5 seconds. It takes this time to write the E2PROM for all the adjustment process parameters of a different mode. (The cursor does not move for a few seconds when the writing is going on.) If you ha ve wrongly turned off the power , once change the MODEL setting to an y other model number, wait for 5 seconds, and change the setting back to the right model number. Then wait for another 5 seconds just to be sure.

● To quit the adjustment process mode with adjustments complete, use the ADJUST PROCESS key on the remote

contoller.

4. Adjustment process items

Adjustment process page number

1 >+B–ADJ 160

MODEL M4U INCH SIZE 20 TIMER 1 SYSTEM AUTO NTSC PWM FREQ 0C0 PAL PWM FREQ 0B0 TV GAIN OFF ERROR NO RESET 0 PMUTE 00 PUBLIC MODE ON COLOR SW

20M4 VER 1.000

Adjustment process settings

Adjustment process items

Microprocessor version

No picture, No sound

Check all the settings microprocessor's adjust process menu.

Do F701 function?

Are T701's secondary

outputs, +34V, +15V, +10V,

+5V and -9V normal?

Remove F701 and

check the load side.

Is there short-circuiting?

Is there short-circuiting of

T701 primary side periphery,

Q701, Q703 and S4001?

Replace F701.

Check S4001 and

connection cable.

Is T701's primary oscillator

waveform normal?

Check T701's secondary

load.

Yes

No No

Yes

Fluorecent lamp failure to light up

Does F4701 and F4702

function?

Is the pin (34) of IC1201 in

the "H" state?

Is the Q1774 short-circuiting?

Is there short-circuiting of

T1701~T1706 primary side

periphery, Q1701~Q1705?

Yes

Replace the fluorecent lamp

with new one and check

again.

Yes

Check the OFL1 line, IC1201

and their peripheral parts.

Check Q1774 and its

peripheral parts.

Check T1701~T1706,

Q1701~Q1705 and

connection cable.

Replace F4701 and F4702.

Yes

TROUBLE SHOOTING TABLE

LC-20M4U

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 voltage

and waveform.

Yes

No picture

at all

Is in/output of

IC402 normal?

Is input at pin

(73) of IC801

normal?

Yes

No VIDEO 1

and VIDEO 2

output

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

Is input at pin

(5) of IC402

normal?

Is the pin (4) of

IC402 in the

"H" state?

Check the its

line.

Check the its

line.

Yes

No VIDEO 2

output

Check IC402

and its

peripheral parts.

Is the pin (68)

of IC2001 in the

"H" state?

No picture

Check all the settings microprocessor's adjust process menu.

Is input at pins

(71) and (72) of

IC801 normal?

No S-VIDEO

output

Check

SC401, SY-line,

SC-line and their

peripheral parts.

Is input at pins (4), (5),

(6) and (75) of IC801

as specified?

No COMPONENT

output

Check J4403, J4404,

J4405, DVD-Y line,

PB line, PR line and

their peripheral parts.

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 its

peripheral parts.

Check IC1109,

Q1101, Q1102,

D1101, R1120,

R1130 and their

peripheral parts.

Check R1231

and its

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 its

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 its

peripheral parts.

Yes

Check R1223

and gate array

peripheral parts.

Becomes

white.

Is 3.3V VSH

being

outputted?

Is source clock

(CK) normal?

Check +3.3V

outputs line of

IC781.

Check R1210,

R1211 and their

peripheral parts.

Check FB1203

and gate array

peripheral parts.

Is output of

LBR and HG

normal?

Yes

Vertical line

output

TROUBLE SHOOTING TABLE (Continued)

LC-20M4U

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

Color is

unusual

Is VLS 5V

being

outputted?

Picture

image is

gloomy

Is in/output of

SPIO and

SPOI normal?

Check R1209

and its

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 its

peripheral parts.

Yes

TROUBLE SHOOTING TABLE (Continued)

+ 36 hidden pages

SHARP LC20M4U Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual