LG L1720B, L1720BL Service Manual

COLOR MONIT OR

SER VICE MANUAL

Website:http://biz.LGservice.com

E-mail:http://www.LGEservice.com/techsup.html

CAUTION

BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS NO. : CL-43

MODEL: L1720B

(L1720BL-AL**R)

( ) **Same model for Service

*To apply the Mstar Chip.

1. LCD CHARACTERISTICS

Type : TFT SXGA LCD Size : 17 inch Pixel Pitch : 0.264 (H) x 0.264 (V) Color Depth : 16.2M colors Electrical Interface : LVDS Surface Treatment : Hard-coating(3H) Operating Mode : Normally White Backlight Unit : Top/Bottom edge side 4-CCFL

(Cold Cathode Fluorescent Lamp)

2. OPTICAL CHARACTERISTICS

2-1. Viewing Angle by Contrast Ratio

≥

10 Left : -60° min., -70°(Typ) Right : +60° min., +70°(Typ) Top :+50° min., +60°(Typ) Bottom : -45°min., -60°(Typ)

2-2. Luminance : 200(min), 250(Typ) 2-3. Contrast Ratio : 300(min), 400(Typ)

3. SIGNAL (Refer to the Timing Chart)

3-1. Sync Signal

• Type : Separate Sync, SOG (Sync On Green) Composite Sync

3-2. Video Input Signal

1) Type : R, G, B Analog

2) Voltage Level : 0~0.71 V

a) Color 0, 0 : 0 Vp-p b) Color 7, 0 : 0.467 Vp-p c) Color 15, 0 : 0.714 Vp-p

3) Input Impedance : 75 Ω

3-3. Operating Frequency

Horizontal : 30 ~ 83kHz Vertical : 56 ~ 75Hz

. Max. Resolution

Analog : 1280 x 1024 / 75Hz

5. POWER SUPPLY

5-1. Power

: AC 100-240V~, 50/60Hz , 1.0A

5-2. Power Consumption

6. ENVIRONMENT

6-1. Operating Temperature: 10°C~35°C (50°F~95°F)

(Ambient)

6-2. Relative Humidity : 10%~80%

(Non-condensing)

6-3. MTBF : 50,000 Hours(Min)

7. DIMENSIONS (with TILT/SWIVEL) FullUp Position

Width : 394 mm (15.51'') Depth : 232 mm (9.13'') Height : 379 mm (14.92'')

Folded Position

Width : 394mm (15.51'') Depth : 127mm (9.13'') Height : 412mm (14.92'')

8. WEIGHT (with TILT/SWIVEL)

Net. Weight : 4.5 kg (9.92 lbs) Gross Weight : 7.6 kg (16.76 lbs)

CONTENTS

SPECIFICATIONS

- 2 -

SPECIFICATIONS ................................................... 2

PRECAUTIONS ....................................................... 3

TIMING CHART ....................................................... 4

OPERATING INSTRUCTIONS ................................ 5

WIRING DIAGRAM ................................................. 6

BLOCK DIAGRAM ................................................... 7

DESCRIPTION OF BLOCK DIAGRAM.....................8

ADJUSTMENT ...................................................... 10

TROUBLESHOOTING GUIDE .............................. 11

PRINTED CIRCUIT BOARD................................... 15

EXPLODED VIEW...................................................17

REPLACEMENT PARTS LIST ...............................19

SCHEMATIC DIAGRAM......................................... 22

MODE

POWER ON (NORMAL)

STAND-BY

SUSPEND

DPMS OFF

H/V SYNC

ON/ON OFF/ON ON/OFF

OFF/OFF

POWER CONSUMPTION

less than 40 W

less than 2 W less than 2 W

less than 2 W

LED COLOR

BLUE AMBER AMBER AMBER

VIDEO

ACTIVE

OFF OFF OFF

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WARNING FOR THE SAFETY-RELATED COMPONENT.

• There are some special components used in LCD monitor that are important for safety. These parts are

marked on the schematic diagram and the replacement parts list. It is essential that these critical

parts should be replaced with the manufacturer’s specified parts to prevent electric shock, fire or other hazard.

• Do not modify original design without obtaining written permission from manufacturer or you will void the original parts and labor guarantee.

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 are grounded through wrist band.

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

• The module not be exposed to the direct sunlight.

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

• If the surface of panel become dirty, please wipe it off with a softmaterial. (Cleaning with a dirty or rough cloth may damage the panel.)

WARNING

BE CAREFUL ELECTRIC SHOCK !

• If you want to replace with the new backlight (CCFL) or inverter circuit, must disconnect the AC adapter because high voltage appears at inverter circuit about 650Vrms.

• Handle with care wires or connectors of the inverter circuit. If the wires are pressed cause short and may burn or take fire.

PRECAUTION

CAUTION

Please use only a plastic screwdriver to protect yourself from shock hazard during service operation.

TIMING CHART

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VIDEO

SYNC

<< Dot Clock (MHz), Horizontal Frequency (kHz), Vertical Frequency (Hz), Horizontal etc... (µs), Vertical etc... (ms) >>

H + 31.469 800 640 16 96 48 V – 70.8Hz 449 350 37 2 60

H – 31.469 840 640 16 96 48 V – 59.94 525 480 10 2 33 H – 37.5 840 640 16 64 120 V – 75 500 480 1 3 16

H – 31.468 900 720 18 108 54 V + 70.09 449 400 12 2 35

H + 37.879 1056 800 40 128 88 V + 60.317 628 600 1 4 23 H + 46.875 1056 800 16 80 160 V + 75.0 625 600 1 3 21 H+/– 49.725 1152 832 32 64 224 V+/– 74.55 667 624 1 3 39 H – 48.363 1344 1024 24 136 160 V – 60.0 806 768 3 6 29 H – 60.123 1312 1024 16 96 176 V – 75.029 800 768 1 3 28

H+/– 68.681 1456 1152 32 128 144 V+/– 75.062 915 870 3 3 39 H+/– 61.805 1504 1152 18 134 200 V+/– 65.96 937 900 2 4 31 H + 63.981 1688 1280 48 112 248 V + 60.02 1066 1024 1 3 38

H + 79.976 1688 1280 16 144 248 V + 75.035 1066 1024 1 3 38

Mode

H/V

Sort

25.175

28.321

25.175

31.5

40.0

49.5

57.283

65.0

78.75

100.0

92.978

108.0

135.0

640x350

70Hz

640x480

60Hz

640x480

75Hz

720x400

70Hz

800x600

60Hz

800x600

75Hz

832x624

75Hz

1024x768

60Hz

1024x768

75Hz

1152x870

75Hz

1152x900

65Hz

1280x1024

60Hz

1280x1024

75Hz

Sync

Polarity

Frequency

Dot

Clock

Total Period

(E)

Video Active Time

(A)

Sync Duration

(D)

Back Porch

(F)

Front Porch

(C)

Resolution

- 5 -

OPERATING INSTRUCTIONS

FRONT VIEW REAR VIEW

Front Control Panel

1. Power Button

Use this button to turn the display on or off.

This Indicator lights up blue when the display operates normally. If the display is in DPM (Energy Saving) mode, this indicator color changes to amber.

2. Button

Use these buttons to choose or adjust items in the On Screen Display.

3. Menu Button

Use this button to enter or exit the On Screen Display.

AUTO/SELECT Button

Use this button to enter a selection in the On Screen Display.

When adjusting your display settings, always press the AUTO/SELECT button before entering the On Screen Display(OSD). This will automatically adjust your display image to the ideal settings for the current screen resolution size (display mode).

The best display mode is 1024x768/60Hz.

See front control panel

D-sub Connect

Power Connect

143 2

This function optimizes the brightness, contrast or color value to the surrounding conditions and settings and enables you to enjoy the most suitable picture by adjusting the surroundings (DAY/NIGHT/USER MODE).

•

TEXT: For viewing letters

•

MOVIE: For viewing movies

•

PHOTO: For viewing pictures or the photographs

•

USER MODE: This function memorizes the manual adjustment -Brightness, Contrast and Color value on the On Screen Display.

100

Bring up Contrast and Brightness adjustment. :

- 6 -

WIRING DIAGRAM

J707

J702

CN1

CN2

CN4

CN5

CN3

Connector Ass’y : P/N: 6631T11016C

Connector Ass’y : P/N: 6631T20024C

Connector Ass’y : P/N: 6631T20008G

Connector Ass’y : P/N: 6631T20023A

- 7 -

D-SUB

MST9111

including

(ADC/LVDS/SCALER )

MTV312

Micom

LCD Module

R,G,B

differential

LVDS

(Low Voltage

Differential

Signaling)

LIPS

AC Input

3.3V

Reg.

2.5V

Reg.

R,G,B, H/V Sync

3.3V

2.5V

3.3V

2.5V

BLOCK DIAGRAM

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DESCRIPTION OF BLOCK DIAGRAM

1. Video Controller Part & Display Data Transmitter Part.(MST9111)

This part amplifies the level of video signal for the digital conversion and converts from the analog video signal to the digital video signal using a pixel clock. The pixel clock for each mode is generated by the PLL. The range of the pixel clock is from 25MHz to 135MHz. This part consists of the Scaler. The Scaler gets the video signal converted analog to digital, interpolates input to 1280 x 1024 resolution signal and outputs 8-bit R, G, B signal to transmitter. Especially pre-amp / ADC / Video controller/ Transmitter are merged to one chip “MST9111” by MSTAR. This part transmit digital signal from the Scaler to the receiver of module.

2. Micom Part

This Part consists of EEPROM IC which stores control data, Reset IC and the Micom. The Micom distinguishes polarity and frequency of the H/V Sync are supplied from signal cable. The controlled data of each modes is stored in EEPROM.

3. Power Part

This part consists of the one 3.3V and one 2.5 regulators to convert power which is provided 5V in LIPS Board. 5V is provided for LCD Panel. Also, 5V is converted 3.3V and 2.5V by regulator. Converted power is provided for IC in the main board.

- 9 -

EMI

COMPONENTS

LINE

100 ~ 240V

INPUT RECTIFIER

AND FILTER

ENERGY

TRANSFER

OUTPUT RECTIFIER

AND FILTER

12V

GND

SIGNAL

COLLECTI

PHOTO-

COUPLER

ISOLATION

PWM

CONTROL

CIRCUIT

HVDC

100KHz

PRIMARY SECONDARY

50 ~ 60Hz

Operation description_LIPS

LIPS Board Block Diagram

1. EMI components.

This part contains of EMI components to comply with global marketing EMI standards like FCC, VCCI CISPR, the circuit included a line-filter, across line capacitor and of course the primary protection fuse.

2. Input rectifier and filter.

This part function is for transfer the input AC voltage to a DC voltage through a bridge rectifier and a bulk capacitor.

3. Energy Transfer.

This part function is transfer the primary energy to secondary through a power transformer.

4. Output rectifier and filter.

This part function is to make a pulse width modulation control and to provide the driver signal to power switch, to adjust the duty cycle during different AC input and output loading condition to achive the dc output stablize, and also the over power protection is also monitor by this part.

5. Photo-Coupler isolation.

This part function is to feed back the dc output changing status through a photo transistor to primary controller to achieve the stabilized dc output voltage.

6. Signal collection.

This part function is to collect the any change from the dc output and feed back to the primary through photo transistor.

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