ViewSonic VA721-2 User manual

Model No. VLCDS 27998-5W

17” Color TFT LCD Display

Service Manual

ViewSonic VA721-2

ViewSonic

381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583

(VA721-2_SM Rev. 1a Jan. 2006)

may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any

language or computer language, in any form or by any means, electronic, mechanical, magnetic,

optical, chemical, manual or otherwise, without the prior written permission of ViewSonic

Corporation.

Disclaimer

ViewSonic makes no representations or warranties, either expressed or implied, with respect to

the contents hereof and specifically disclaims any warranty of merchantability or fitness for any

particular purpose. Further, ViewSonic reserves the right to revise this publication and to make

changes from time to time in the contents hereof without obligation of ViewSonic to notify any

person of such revision or changes.

Trademarks

Optiquest is a registered trademark of ViewSonic Corporation.

ViewSonic is a registered trademark of ViewSonic Corporation.

All other trademarks used within this document are the property of their respective owners.

Revision History

Revision

SM Editing Date

ECR Number

Description of Changes Editor

1a 01/24/2006 Initial release Jamie Chang

ViewSonic Corporation Confidential -Do Not Copy VA721-2

TABLE OF CONTENTS

1. Precautions and Safety Notices 1

2. Specification 5

3. Front Panel Function Control Description 8

4. Circuit Description 14

5. Adjustment Procedure 24

6. Troubleshooting Flow Chart 47

7. Recommended Spare Parts List 49

8. Exploded Diagram and Exploded Parts List 51

9. Block Diagram 54

10. Schematic Diagrams 56

11. PCB Layout Diagrams 62

ViewSonic Corporation Confidential -Do Not Copy VA721-2

1. Appropriate Operation

(1) Turn off the product before cleaning.

(2) Use only a dry soft cloth when cleaning the LCD panel surface.

(3) Use a soft cloth soaked with mild detergent to clean the display housing.

(4)Use only a high quality, safety approved AC/DC power cord.

(5)Disconnect the power plug from the AC outlet if the product will not be used for a long period of time.

(6) If smoke, abnormal noise, or strange odor is present, immediately switch the LCD display off.

(7) Do not touch the LCD panel surface with sharp or hard objects.

(8) Do not place heavy objects on the LCD display, video cable, or power cord.

(9) Do not use abrasive cleaners, waxes or solvents for your cleaning.

(10) Do not operate the product under the following conditions:

- Extremely hot, cold or humid environment.

-Areas containing excessive dust and dirt.

- Near any appliance generating a strong magnetic field.

- In direct sunlight.

2. Caution

No modification of any circuit should be attempted. Service work should only be performed after you are thoroughly familiar

with all of the following safety checks and servicing guidelines.

3. Safety Check

Care should be taken while servicing this LCD display. Because of the high voltage used in the inverter circuit, the voltage is

exposed in such areas as the associated transformer circuits.

4. LCDModule Handling Precautions

4.1 Handling Precautions

(1) Since front polarizer is easily damaged, pay attention not to scratch it.

(2)Be sure to turn off power supply when connecting or disconnecting input connector.

(3)Wipe off water drops immediately. Long contact with water may cause discoloration or spots.

(4) When the panel surface is soiled, wipe it with absorbent cotton or other soft cloth.

(5) Since the panel is made of glass, it may break or crack if dropped or bumped on hard surface.

(6)Since CMOSLSI isusedinthis module, take care of static electricity and ensure human earth when handling.

(7)Do not open or modify the Module Assembly.

(8)Do not press the reflector sheet at the back of the module in any direction.

(9)In the event that a Module must be put back into the packing container slot after it was taken out of the

container, do not press the center of the CCFL Reflector edge. Instead, press at the far ends of the

CFL Reflector edge softly. Otherwise the TFT Module may be damaged.

(10) At the insertion or removal of the Signal Interface Connector, be sure not to rotate or tilt the Interface

Connector of the TFT Module.

1. Precautions and Safety Notices

ViewSonic Corporation Confidential -Do Not Copy VA721-2

(11) After installation of theTFT Module intoan enclosure(LCDmonitor housing, for example), do not twist or

bend the TFT Module even momentarily. When designing the enclosure, it should be taken into consideration

that no bending/twisting forces may be applied to the TFT Module from outside. Otherwise theTFT Module

may be damaged.

(12) The cold cathode fluorescent lamp in the LCD contains a small amount of mercury. Please follow local

ordinances or regulations fordisposal.

(13) The LCD module contains a small amount of materials having no flammability grade. The LCD module

should be supplied with power that complies with the requirements of Limited Power Source

(IEC60950 or UL1950), or an exemption should be applied for.

(14) The LCD module is designed so that the CCFL in it is supplied by a Limited Current Circuit (IEC60950

or UL1950). Do not connect theCCFL to a HazardousVoltage Circuit.

ViewSonic Corporation Confidential -Do Not Copy VA721-2

Correct methods : Incorrect Methods :

5. Handling Methods

Only touch the metal frame of the panel or the front

cover of the monitor.

Do not touch the surface of the polarizer .

If the surface of the panel is pressed by fingers, this

may cause "MURA."

Take out the monitor by grasping the cushion. If the monitor is removed by grasping the LCD

panel, that may cause "MURA."

ViewSonic Corporation Confidential -Do Not Copy VA721-2

Correct methods : Incorrect Methods :

Place the monitor on a clean & soft foam pad .

If the monitor is placed on foreign objects,

that could scratch the surface of the panel.

ViewSonic Corporation Confidential -Do Not Copy VA721-2

•General Specifications

Test Resolution & Frequency 1280 x 1024 @ 60Hz

Test Image Size Full Size

Contrast and Brightness Controls Factory Default: Contrast = 70%, Brightness =

100%

•Video Interface

Analog Input Connector DB-15 (Analog)

Video Cable Strain Relief Equal to twice the weight of the monitor for five

minutes.

Video Cable Connector DB-15 Pinout Compliant DDC 2B.

Video Signals Video RGB (Analog)

Video Impedance 75 Ohms (Analog)

Maximum PC Video Signal 950 mV with no damage to monitor

Maximum Mac Video Signal 1250 mV with no damage to monitor

Sync Signals TTL

DDC 1/2B Compliant with Revision 1.3

Video Compatibility Shall be compatible with all PC type computers,

Macintosh computers, and after market video

cards.

Resolution Compatibility 640 x 350, 640 x 480, 720 x 400 (640 x 400), 800 x

600, 832 x 624, 1024 x 768, 1280 x 720, 1280 x

1024

Exclusions Not compatible with interlaced video.

•Power Supply

Internal Power Supply Part Number: ADP-40AFB

Input Voltage Range 90 TO 264 VAC

Input Frequency Range 47.5 TO 63 HERTZ

Short Circuit Protection Output can be shorted without damage.

Over Current Protection 4.5 A typical at 12 VDC

Leakage Current 3.5mA (Max) at 254VAC / 60Hz

EFFICIENCY 70 % typical at 115VAC Full Load

Fuse Internal and not user replaceable

Power Dissipation 35 Watts (typ)

Max Input AC Current 1.2 Arms @ 90VAC, 0.8 Arms @180VAC

2. Specification

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•Horizontal / Vertical Frequency

Horizontal Frequency 30 – 80 KHZ

Vertical Refresh Rate 50 –85 HZ.

Maximum Pixel Clock 135 MHz

Sync Polarity Independent of sync polarity.

Primary Presets

Primary Preset 1280 x 1024 @ 60Hz

Look up table timing

<<Analog>>

1. 640 x 350 @ 70Hz, 31.5kHz

2. 640 x 480 @ 60Hz, 31.5kHz

3. 640 x 480 @ 67Hz, 35.0kHz

4. 640 x 480 @ 75Hz, 37.5kHz

5. 640 x 480 @ 72Hz, 37.9kHz

6. 640 x 480 @ 85Hz, 43.27kHz

7. 720 x 400 @ 70Hz, 31.5kHz

8. 800 x 600 @ 56Hz, 35.1kHz

9. 800 x 600 @ 60Hz, 37.9kHz

10. 800 x 600 @ 75Hz, 46.9kHz

11. 800 x 600 @ 72Hz, 48.1kHz

12. 800 x 600 @ 85Hz, 53.7kHz

13. 832 x 624 @ 75Hz, 49.7kHz

14. 1024 x 768 @ 60Hz, 48.4kHz

15. 1024 x 768 @ 70Hz, 56.5kHz

16. 1024 x 768 @ 72Hz, 58.1kHz

17. 1024 x 768 @ 75Hz, 60.0kHz

18. 1024 x 768 @ 85Hz, 68.67kHz

19. 1280 x 1024 @ 60Hz, 63.4kHz

20. 1280 x 1024 @ 75Hz, 79.97kHz

21. 1280x720 @ 60Hz, 45kHz (HDTV)

Changing Modes

Maximum Mode Change Blank Time, for

image stability. Note:

1) Excluding “Auto Adjust” time

2) Under DOS mode (640 x 350, 720 x 400 & 640 x

400), there is no “Auto Adjust” feature.

3) The monitor needs to do “Auto Adjust” the first

time a new mode is detected.

3 seconds (Max)

1 seconds (Typ) for recognized timings

1-2 seconds (Typ) for unrecognized timing

Mode Change Image The image shall blank while the monitor changes

modes.

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1. ID Label -The panel code “Q” for QDI / “C” for CPT, it should be shown on the lower right

side.

2. UPC Label -The panel code “Q” for QDI / “C” for CPT, it should be shown on the lower

right side

3. Main Board -The panel code “Q” for QDI / “C” for CPT, it should be shown on the main

board by F/W version sticker

Panel Characteristics:

Panel Source CPT CLAA170EA 07Q

Type TN, LVDS

Active Size 337.9 mm (H) x 270.3mm (V)

Pixel Arrangement RGB Vertical Stripe

Pixel Pitch 0.264 mm

Glass Treatment Anti Glare (Hard coating 3H)

# of Backlights 4CCFL edge-light

Backlight Life (Hours) 30,000 (Min)

Luminance –Center Point (CT=6500K)

Contrast/Brightness=Max 300 cd/m2 (Typ after 30 minute warm up)

250 cd/m2 (Min after 30 minute warm up)

Brightness Uniformity (5 points ,the

location follows up CPT spec) 75% min

Contrast Ratio 500 :1 (Typ), 450 :1 (Min)

Color Depth Vertical) 16.2 million colors

Viewing Angle (Horizontal, typ)140 deg @CR>10 / 170 deg @ CR>5

Viewing Angle (Vertical, typ)130 deg @ CR>10 / 160 deg @ CR>5

Response Time

10%-90% @ Ta=25°C 8ms (Typ)

12 ms (Max)

Panel Defects Please see Panel Quality Specifications.

Panel Source QDI QDI17EL0709

Type TN, dual LVDS

Active Size 337.9 mm (H) x 270.3mm (V)

Pixel Arrangement RGB Vertical Stripe

Pixel Pitch 0.264 mm

Glass Treatment Anti Glare (Hard coating 3H)

# of Backlights 4CCFL edge-light

Backlight Life (Hours) 40,000 (Min)

Luminance –Center Point (CT=6500K)

Contrast/Brightness=Max 260 cd/m2 (Typ after 30 minute warm up)

200 cd/m2 (Min after 30 minute warm up)

Brightness Uniformity (5 points ,the

location follows up CPT spec) 80%(typ) / 75% (min)

Contrast Ratio 500 :1 (Typ), 300 :1 (Min)

Color Depth Vertical) 16.2 million colors

Viewing Angle (Horizontal, typ)140 deg @CR>10

Viewing Angle (Vertical, typ)125 deg @ CR>10

Response Time

10%-90% @ Ta=25°C 8ms (Typ)

Panel Defects Please see Panel Quality Specifications.

•LCD Panel

ViewSonic Corporation Confidential -Do Not Copy VA721-2

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