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Service Manual
ViewSonic VA2012w
VA2012wb
Model No. VS10859
20" Color TFT LCD Display
(VA2012w_VA2012wb_SM Rev. 1a Nov. 2005 )
ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583
Copyright
Copyright 2005 by ViewSonic Corporation. All rights reserved. No part of this publication 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 11/29/05 Initial Release BonnieT.
ViewSonic Corporation Confidential - Do Not Copy VA2012wb
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TABLE OF CONTENTS
1. Precautions and Safety Notices 1
2. Specification 5
3. Front Panel Function Control Description 12
4. Circuit Description 14
5. Adjustment Procedure 25
6. Troubleshooting Flow Chart 51
7. Recommended Spare Parts List 54
8. Exploded Diagram and Exploded Parts List 60
9. Block Diagram 64
10. Schematic Diagrams 65
11. PCB Layout Diagrams 72
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1. Precautions and Safety Notices
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. LCD Module 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 CMOS LSI is used in this 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.
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(11) After installation of the TFT Module into an enclosure (LCD monitor 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 the TFT 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 for disposal.
(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 the CCFL to a Hazardous Voltage Circuit.
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VA2012w series handling Notice
Correct Method Incorrect method
Correct Method Incorrect method
Correct Method Incorrect method
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Correct Method Incorrect method
Correct Method Incorrect method
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2. Specificationtion
GENERAL specification
Test Resolution & Frequency "1680 X 1050" @ 60Hz
Test Image Size Full Size
Factory Default:
Contrast and Brightness Controls
Contrast = 70%, Brightness = 100%
VIDEO INTERFACE
Analog Input Connector DB-15 (Analog), refer the appendix A
Digital Input Connector DVI-D (Digital), refer the appendix B
Default Input Connector Defaults to the first detected input
Equal to twice the weight of the monitor for
Video Cable Strain Relief
five minutes
Video Cable Connector DB-15 Pin out Compliant DDC 1/2B
1. Video RGB (Analog)
Video Signals Separate
2. TMDS (Digital)
Video Impedance 75 Ohms (Analog), 100 Ohms (Digital)
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
Sync Compatibility Separate Sync
Shall be compatible with all PC type
Video Compatibility computers, Macintosh computers, and after
market video cards
640 x 350, 640 x 480, 720 x 400 (640 x
400), 800 x 600, 832 x 624, 1024 x 768,
Resolution Compatibility
1280 x 720, 1280 x 1024, 1600 x 1200,
1680 x 1050
Exclusions Not compatible with interlaced video
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POWER SUPPLY
Internal Power Supply Part Number: EADP-64CF
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 Output current <10A
Leakage Current 3.5mA (Max) at 254VAC / 60Hz
EFFICIENCY 80 % typical at 115VAC Full Load
Fuse Internal and not user replaceable
Power Dissipation 64 Watts (typ)
Max Input AC Current 1.5 Arms @ 90VAC
INRUSH CURRENT (COLD START) 80 A(max) @230VAC
Shall start and function properly when under
full load, with all combinations of input
Power Supply Cold Start
voltage, input frequency, and operating
temperature
Shall be able to withstand an ANSI/IEEE
Power Supply Transient Immunity C62.41-1980 6000V 200 ampere ring wave
transient test with no damage
Shall be able to withstand 1.5 times nominal
Power Supply Line Surge Immunity
line voltage for one cycle with no damage
Shall be able to function properly, without
reset or visible screen artifacts, when