ViewSonic VA2012w-2 User manual

ViewSonic VA2012w-2
VA2012wb-2
Model No. VS10859
20” Color TFT LCD Display
(VA2012w-2_VA2012wb-2_SM Rev. 1aJun. 2006)
ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA- [phone]
Service Manual

ViewSonic Corporation Confidential - Do Not Copy VA2012w-2_VA2012wb-2
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Copyright
Copyright © 2006 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
Opt quest 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 6/19/2006 Initial Release J. Chang

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TABLE OF CONTENTS
1. Precautions and Safety Notices 1
2. Specification 4
3. Front Panel Function Control Description 10
4. Circuit Description 12
5. Adjustment Procedure 25
6. Troubleshooting Flow Chart 50
7. Recommended Spare Parts List 53
8. Exploded Diagram and Exploded Parts List 58
9. Block Diagram 62
10. Schematic Diagrams 63
11. PCB Layout Diagrams 70

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1. Precautions and Safety Notices
1. 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 guide line
2. Safety Check :
Care should be taken while servicing this LCD display. Because of the high voltage used in the inverter circuit. These
voltage are exposed in such areas as the associated transformer circuits .
3. POWER SUPPLY REQUIREMENTS
The external power converter for this display utilizes AC and DC cords , AC cord is detachable , but DC cord is
permanently attached .Any attempt to replace another adapter could result in serious problem on the display .
4. LEAKAGE CURRENT HOT CHECK
4-1 Plug the AC cord directly into the AC outlet. Do not use an isolation transformer during this check.
4-2 Connect a 1500 ohm , 10 watt resistor , paralleled by a 0.15uF capacitor between each metallic part and a good earth
ground
4-3 Use an AC voltmeter with 1000 ohm / volt or more sensitivity and measure the AC voltage across the combination
1500 ohm resistor and 0.15uF capacitor.
4-4 Move the resistor connection to each exposed metallic part and measure the voltage.
4-5 Reverse the polarity of the AC plug in the AC outlet and repeat the above measurement.
4-6 Voltage measured must not exceed 1.5 volt RMS, from any exposed metallic part to the ground.A leakage current
tester may be used in the above hot check, in which case any circuit measured must not exceed 1.0 milliamp. In the
case of a measurement exceeding the 1.0 milliamp value, a rework is required to eliminate the chance of a shock
hazard .
To Metal Parts
V
AC VOLTMETER
1500 10W
0.15u
.
Earth Ground

Take out the monitor with cushion
correct method
Place the monitor on a clean & soft foam pad
Surface of the panel is pressed by fingers &
this may cause “ MURA “
Do not touch the surface of the polarizer .
incorrect method
Take out the monitor by grasping the LCD
panel. That may cause “ MURA“.
could
scratch the surface of panel
Handing and Placing Methods
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when assemble&disassembly
bezel
when assemble&disassembly
bezel
when assemble&disassembly
bracket
when assemble&disassembly
bracket
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2. Specification
GENERAL specification
Test Resolution & Frequency “1680 X 1050” @ 60Hz
Test Image Size Full Size
Contrast and Brightness Controls Factory Default:
Contrast = 70%, Brightness = 100%
VIDEO INTERFACE
Analog Input Connector DB-15 (Analog), refer the appendix A
Digital Input Connector N/A
Default Input Connector Defaults to the first detected input
Video Cable Strain Relief Equal to twice the weight of the monitor for five minutes
Video Cable Connector DB-15 Pin out Compliant DDC 1/2B
Video Signals 1. Video RGB (Analog) :Separate
2. TMDS (Digital)—N/A
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
Sync Compatibility Separate Sync
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, 1600 x
1200, 1680 x 1050
Exclusions Not compatible with interlaced video
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
Power Supply Cold Start
Shall start and function properly when under full load, with all
combinations of input voltage, input frequency, and operating
temperature

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Power Supply Transient Immunity Shall be able to withstand an ANSI/IEEE C62.41-1980 6000V 200
ampere ring wave transient test with no damage
Power Supply Line Surge Immunity Shall be able to withstand 1.5 times nominal line voltage for one
cycle with no damage
Power Supply Missing Cycle Immunity
Shall be able to function properly, without reset or visible screen
artifacts, when ½ cycle ofAC power is randomly missing at
nominal input
Power Supply Acoustics
The power supply shall not produce audible noise that would be
detectable by the user. Audible shall defined to be in compliance
with ISO 7779 (DIN EN27779:1991) Noise measurements of
machines acoustics. Power Switch noise shall not be considered
US Type Power Cable Separate 3-prong NEMA 5-15P type plug. Length = 1.8m.
Connects to AC outlet. Color = Black
European Type Power Cable Schuko CEE7-7. Length = 1.8m, Connects to AC outlet. Color =
Black
Power Saving Operation(Method) VESA DPMS Signaling
Power Consumption ON Mode < 50 W (max) / 47 W (typ)
ACTIVE OFF < 2W
Recovery Time ON Mode = N/A, ACTIVE OFF < 3 sec
ELECTRICAL REQUIREMENT
Horizontal / Vertical Frequency
Horizontal Frequency Analog: 30 – 94 kHz
Vertical Refresh Rate 50 – 75 Hz.
Maximum Pixel Clock Analog: 205 Mhz
Sync Polarity Independent of sync polarity.
Timing Table
Item Timing Analog Digital
1 640 x 350 @ 70Hz, 31.5kHz Yes N/A
2 640 x 400 @ 70Hz, 31.5kHz Yes N/A
3 640 x 480 @ 60Hz, 31.5kHz Yes N/A
4 640 x 480 @ 67Hz, 35.0kHz Yes N/A
5 640 x 480 @ 72Hz, 37.9kHz Yes N/A
6 640 x 480 @ 75Hz, 37.5kHz Yes N/A
7 720 x 400 @ 70Hz, 31.5kHz Yes N/A
8 720 x 480i 59.94/60Hz @ 15.7 kHz Yes N/A
9 720 x 576p 50Hz @ 31.25kHz Yes N/A
10 720 x 576i 50Hz @ 15.62kHz Yes N/A
11 800 x 600 @ 56Hz, 35.1kHz Yes N/A

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12 800 x 600 @ 60Hz, 37.9kHz Yes N/A
13 800 x 600 @ 75Hz, 46.9kHz Yes N/A
14 800 x 600 @ 72Hz, 48.1kHz Yes N/A
15 832 x 624 @ 75Hz, 49.7kHz Yes N/A
16 1024 x 768 @ 60Hz, 48.4kHz Yes N/A
17 1024 x 768 @ 70Hz, 56.5kHz Yes N/A
18 1024 x 768 @ 72Hz, 58.1kHz Yes N/A
19 1024 x 768 @ 75Hz, 60.0kHz Yes N/A
20 1280x720p 50Hz @ 37.5kHz Yes N/A
21 1280x 720p @ 60Hz, 45kHz Yes N/A
22 1280 x 1024 @ 60Hz, 63.4kHz Yes N/A
23 1280 x 1024 @ 75Hz, 79.97kHz Yes N/A
24 1600 x 1200 @ 60Hz, 75kHz Yes N/A
25 1600 x 1200 @ 70Hz, 87.5kkHz Yes N/A
26 1600 x 1200 @ 75Hz, 93.8kHz Yes N/A
27 1680 x 1050 @ 60Hz, 65.3 kHz Yes N/A
28 1680 x 1050 @ 75Hz, 82.3 kHz Yes N/A
29 1920 x 1080i @ 50Hz, 56.5kHz Yes N/A
30 1920 x 1080p @ 50Hz, 62.5kHz Yes N/A
Primary Presets
“1680 x 1050” @ 60Hz
User Presets
Number of User Presets (recognized timings) Available: 10 presets total in FIFO configuration
Changing Modes
zMaximum Mode Change Blank Time for image stability : 3 seconds (Max), excluding “Auto Adjust” time
zUnder DOS mode (640 x 350, 720 x 400 & 640 x 400), it should recall factory setting when execute
“Auto Adjust”
zThe monitor needs to do “Auto Adjust” the first time a new mode is detected
z(see section “0-Touch™ Function Actions”)
zWhile running Change Mode, Auto Adjust or Memory Recall, the image shall blank

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AUDIO INTERFACE (SPEAKER SPECIFICATION)
Line input connection 3.5 mm stereo jack
Line input signal 1.3 Vrms
Line input impedance 10 kOhm
Maximum power output (Electric) 1 W @ < 5% distortion
Signal to Noise Ratio 72 dB
Frequency response 200 Hz – 20 Khz
Distortion < 5 % THD (@1kHz)
Vibration There should be no audible vibration with volume at 100% and
treble / bass at default
Screen image There should be no affect on the screen image stability under any
conditions
Connector PC99 requirement Audio in Lime Green pantone # 577C
Cable type / length 3.5mm stereo cable / 1.8m length
Panel Characteristics:
1st Source Panel QDI QD20AL01
Type TN Technology”
Active Size 433.44 (H) x 270.9 (V)
Pixel Arrangement RGB Vertical Stripe
Pixel Pitch 0.258 mm
Glass Treatment Anti Glare (Hard coating 3H)
# of Backlights 6 CCFL edge-light (3 top / 3 bottom)
Backlight Life 40,000 Hours (Min)
Luminance – Condition:
CT = 6500K, Contrast = Max, Brightness = Max
300 cd/m2 (Typ after 30 minute warm up)
240 cd/m2 (Min after 30 minute warm up)
Brightness Uniformity 77 % Entire Area (typ)
Contrast Ratio 600:1 (Typ), 400:1 (Min)
Color Depth 16.2 million colors (6 bit panel)
Viewing Angle (Horizontal) 140 deg @ CR>10, 160 deg @ CR>5
Viewing Angle (Vertical) 125 deg @ CR>10, 140 deg @ CR>5
Response Time
10%-90% @ Ta=25°C
8 ms (Tr= 2 ms, Tf = 6 ms) (Typ)
16 ms (Tr= XXX ms, Tf = XXX ms) (Max)
Panel Defects Please see Panel Quality Specifications.