Viewsonic VG921M-2 Service Manual

Service Manual

ViewSonic VG921m-2

Model No. VS11313

19” Color TFT LCD Display

(VG921m-2_SM Rev. 1a Jan. 2007)

ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - [phone]

Copyright

Copyright © 2007 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 12/20/2006 Initial Release Jamie Chang

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TABLE OF CONTENTS

1. Precautions and Safety Notices 1

2. Specification 3

3. Front Panel Function Control Description 6

4. Circuit Description 13

5. Adjustment Procedure 14

6. Troubleshooting Flow Chart 34

7. Block Diagram 36

8. Schematic Diagrams 37

9. PCB Layout Diagrams 47

10. Exploded Diagram and Exploded Parts List 55

11. Recommended Spare Parts List 58

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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) Disconnect the power plug from AC outlet if the product is not used for a long period of time.

(5) If smoke, abnormal noise, or strange odor is present, immediately switch the LCD display off.
(6) Do not touch the LCD panel surface with sharp or hard objects.
(7) Do not place heavy objects on the LCD display, video cable, or power cord.
(8) Do not use abrasive cleaners, waxes or solvents for your cleaning.
(9) Do not operate the product under the following conditions:

- Extremely hot, cold or humid environment.

- Areas susceptible to excessive dust and dirt.

- Near any appliance generating a strong magnetic field.

- Place 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. Power Supply Requirements

The external AC power operating range shall be from 90 to 264Vac

5. LCD Module Handling Precautions

5.1. Handling Precautions

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

(2) Be sure to turn off power supply when inserting or disconnecting from input connector.
(3) Wipe off water drop 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 insure human earth when

handling.
(7) Do not open nor modify the Module Assembly.
(8) Do not press the reflector sheet at the back of the module to any directions.

(9) In case if a Module has to be put back into the packing container slot after once it was taken out from

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 nor tilt the Interface

Connector of the TFT Module.

(11) After installation of the TFT Module into an enclosure (LCD monitor housing, for example),

do not twist nor bend the TFT Module even momentary. At designing the enclosure, it should be taken
into consideration that no bending/twisting forces are applied to the TFT Module from outside.
Otherwise the TFT Module may be damaged.

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

ordinances or regulations for disposal.

(13) Small amount of materials having no flammability grade is used in the LCD module. The LCD module

should be supplied by power complied with requirements of Limited Power Source, or be applied
exemption.

(14) The LCD module is designed so that the CFL in it is supplied by Limited Current Circuit.

Do not connect the CFL in Hazardous Voltage Circuit.

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5.2 Handling and Placing Methods
Correct Methods: Incorrect Methods:

1.Take out the monitor with cushions 1.Taking out the monitor by grasping the LCD panel.
That may cause ”Mura”

2.Only touch the metal frame of the LCD panel or the

front cover of the monitor. Do not touch the surface of
the polarizer.

2.Surface of the LCD panel is pressed by fingers and
that may cause ”Mura”.

3.Place the monitor on a clean and soft foam pad. 3.Placing the monitor on foreign objects. That could
scratch the surface of the panel or cause “Mura”.

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2. Specification

FEATURES VG921m

Size

Luminance (Typ)

TFTLCD PANEL

1st

HSD

HSD190SEN1-A04

Input Signal

Sync Compatibility

Compatibility

Power Voltage AC 100-240V, 50/60Hz Yes

Contrast Ratio (Typ) *1 700:1

Colors 16.2 M (6 bits + 2 bits FRC)

Response Time *1 8 ms (on/off)

Viewing Angle (H/V) 150 ° / 135 °@ CR ≥ 10

160 ° / 160 °@ CR ≥ 5

Recommend resolution 1280x1024@60Hz

Analog Yes (75ohms, 0.7/1.0 Vp-p)

Digital NO

Separate Sync Yes

Composite Sync Yes

Sync on Green Yes

PC Yes

Power Mac Yes

19 "

300 cd/㎡

On Mode(Max) ≦ 36 W Power

Consumption

Audio 1.5W / THD 0.5% (Max) Yes

Ergonomics

OSD Control [ 1 ] [ 2 ] [ ] [▼] [▲] [Mute] Yes

Dimension

Weight

Operating

Condition

Storage Condition

Off Mode (Max) ≦1 W

Tilt ( 20 ° - -5 °)

Swivel No

Pivot No

Height Adjust No

Physical (W x H x D) 425.4 mm x 457.7 mm x 205 mm

Package (W x H x D) 497 mm x 516 mm x 158 mm

Physical (Net Weight) 5.2Kg (11.5 lbs)

Package (Gross Weight) 6.8Kg (14.9 lbs)
Temperature (℉/℃) 32℉-104℉ / 0℃-40℃

Humidity (%) 20 % - 80 %
Temperature (℉/℃) -4℉-140℉ / -20℃-60℃

Humidity (%) 10% - 90 % (no condensation)

Yes

UL/CUL, FCC (ICES-003B), CB, CE, TCO'03, GS, ERGO(covers

ISO13406-2 & MPRII), IRAM, VCCI, GOST-R, HYGIENIC (20

Regulation

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copies), Energy Star, CCC, BSMI, PSB, C-TICK, SASO, WEEE,

RoHS, Windows Vista Basic

 Audio Interface (Speaker Specification)

Line input connection 3.5 mm stereo jack
Line input signal 1.0 Vrms
Line input impedance 10 kOhm
Maximum power output (Electric) 1.2 W / ch
Speaker 1.5W / ch (max)
Signal to Noise Ratio 50 dB
Frequency response 100 Hz – 20 kHz
Distortion < 10 % THD (@1kHZ)

Vibration

Screen image

Connector PC99 requirement Audio in Lime Green pantone # 577C
Cable type / length 3.5mm stereo cable / 1.8m length

Audio DPMS

 Panel Characteristics:

1st Source Panel

There should be no audible vibration with
volume at 100% and treble / bass at default.
There should be no affect on the screen
image stability under any conditions.

Speakers should be off when the rest of the
monitor is in power saving.

Model number HSD190SEN1-A04

Type Active Matrix TFT, TN technology

Active Size 19” (376.32mm x 301.056mm)

Pixel Arrangement RGB Vertical Stripe

Pixel Pitch 0.294 mm

Glass Treatment Anti-Glare, Hard coating (3H)

# of Backlights 4 CCFL

Backlight Life 50000 Hrs (Min)

Luminance (Center) –

CT = 6500K,

Contrast/ Brightness = Max

300 cd/m2 (Typ)

240 cd/m2 (Min)

Brightness Uniformity (13 points) 75 % (Min)

Contrast Ratio 700 :1 (Typ)

450 : 1 (Min)

Color Depth 16.2 million colors (6+2 bit panel)

150 degrees (Typ) / 130 degrees (Min) @ CR>10

Horizontal Viewing Angle

160 degrees (Typ) @ CR>5

Vertical Viewing Angle

135 degrees (Typ) / 110 degrees (Min) @ CR>10

160 degrees (Typ) @ CR>5

Response Time

On-Off

10%-90% @ Ta=25°C 8ms (Typ) / 12ms (Max)

Mercury 3.0 mg per lamp

Panel Defects Please see Panel Quality Specifications.

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ELECTRICAL REQUIREMENT

Horizontal / Vertical Frequency

Horizontal Frequency

Vertical Refresh Rate

Maximum Pixel Clock 135 MHz

Sync Polarity Independent of sync polarity

Timing Table

Item Timing

1 640 x 350 @ 70 Hz, 31.5 KHz

2 640 x 400 @ 60 Hz, 31.5 KHz

3 640 x 400 @ 70 Hz, 31.5 KHz

640 x 480 @ 50 Hz, 24.7 KHz

4

5 640 x 480 @ 60 Hz, 31.5 KHz

24 – 82 kHz

50 – 75 Hz

Analog

Composite

Separated











Digital - TMDS

SOG

The image quality might be
worse than 640x480@60Hz

Remark

640 x 480 @ 67 Hz, 35 KHz

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7 640 x 480 @ 72 Hz, 37.9 KHz

8 640 x 480 @ 75 Hz, 37.5 KHz

9 720 x 400 @ 70 Hz, 31.5 KHz

10 800 x 600 @ 56 Hz, 35.1 KHz

11 800 x 600 @ 60 Hz, 37.9 KHz

12 800 x 600 @ 72 Hz, 48.1 KHz

13 800 x 600 @ 75 Hz, 46.9 KHz

14 832 x 624 @ 75 Hz, 49.7 KHz

15 1024 x 768 @ 60 Hz, 48.4 KHz

16 1024 x 768 @ 70 Hz, 56.5 KHz

17 1024 x 768 @ 75 Hz, 60 KHz

18 1152 x 864 @ 75 Hz, 67.5 KHz

19

1152 x 870 @ 75 Hz, 68.7 KHz

20 1280 x 720 @ 60 Hz, 45 KHz































DMT

DMT

DMT

DMT

DMT

DMT

MAC

DMT

DMT

DMT

DMT

For MAC

DTV

21 1280 x 1024 @ 60 Hz, 64 KHz

22 1280 x 1024 @ 75 Hz, 80 KHz

*1. Tolerance ≧ ±2KHz (if no overlapping issue)

*2. Any timing not in the list, it should display as normal or show on “OUT OF RANGE” OSD message without

blanking.

*3. The image quality of 50Hz mode might be worse than 60Hz.

5





DMT

DMT

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3. Front Panel Function Control Description

3.1 Front Panel Hardware Controls

Power Switch (Front Head) Power Control, soft Power Switch.

Power LED (Front Head) Green – ON

Orange – Power Saving Mode

Dark = Soft Power Switch OFF

Front Panel Controls (Head)

[

] [ 1 ] [ 2 ] [▲] [▼] [;X]

Reaction Time OSD must fully appear within 0.5s after pushing Button 1

3.2 Short Cuts Function from the button(s)

[1] Main Menu

[2] Auto Image Adjust

[▼] Brightness adjust

[▲] Contrast adjust

[▼]+ [▲] recall both of Contrast and Brightness to default

[;X] Mute

[

] Power

[ 1 ] BUTTON 1

[ 2 ] Button 2

[▲] UP ARROW BUTTON
[▼] DOWN ARROW BUTTON

Note: Power Button, Button 1 and Button 2 must be one-shot logic

operation. (i.e. there should be no cycling)

[1] + [2] 1. toggle 720x400@70Hz/640x400@70Hz mode when input one of the two mode

2. toggle 640x480@60Hz/640x400@60Hz mode when input one of the two mode

[1] + [▼] + [▲] White Balance.

*1. Not shown on user’s guide

*2. Recommend resolution = 640x480@60Hz)

[1] + [▼] Power Lock

[1] + [▲] OSD Lock

Signal + [1] + [ ] Factory Mode (include burning mode)

Remark : All the short cuts function are only available while OSD off

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3.3 Function descriptions

Main Menu Controls

The Main Menu OSD includes most of control functions.

Please refer to APPENDIX C (Main Menu OSD Table) for the detail.
OSD Lock short cuts function for the buttons

The OSD lock will be activated by pressing the front panel control buttons "(1), & (▲)" for 10 seconds. If the user then tries to

access the OSD by pressing any of the buttons "1", "▼", "▲", "2" a message will appear on the screen for 3 seconds showing

"OSD Locked". The OSD lock will be deactivated by pressing the front panel control buttons "(1), & (▲)" again for 10

seconds.

Note 1: When the OSD is locked will lock all functions, including “Volume” and “Mute”

Note 2: Status bar indicating OSD Lock or Unlock is in progress and when complete it will indicate “OSD Locked”

Note 3: OSD Lock should not lock Power Button and Power Lock function
Power Lock short cuts function for the buttons

The power button lock will be activated by pressing the front panel control buttons "(1), & (▼)" for 10 seconds. Locking the

power button means that the user won't be able to turn off the LCD while the power button is locked. If the user presses the

power button while it is locked, a message will appear on the screen for 3 seconds showing "Power Button Locked". It also

means that with the power button locked, the LCD would automatically turn back "On" when power is restored after a power

failure. If the power button is not in the locked mode, then power should return to it's previous state when power is restored

after a power failure. The power button lock will be deactivated by pressing the front panel control buttons "(1), & (▼)" again

for 10 seconds.

Note 1: Status bar indicating Power Button lock or unlock is in progress and when complete it will indicate “Power Button

Locked”

Note 2: Power should only be lockable in the “On State”

Memory Recall Actions

Memory Recall action as below

1. Recall white balance to factory setting

2. Set the factory defaults as shown in Section 4-8

3. Clean all the mode setting buffer

4. Execute Auto Image Adjust

Note: Memory Recall should have no effect for Language, Power Lock, User Color Settings or Input Priority

Input Signal Notice Actions

1. The Input Signal Notice OSD appears 3 seconds when power turns on or change input signal.

2. The Input Signal Notice OSD position is on the right-bottom side of image. And the OSD background shall be transparent.

(OSD Background = off).

Resolution Notice Ac tions

1. Resolution Notice OSD should show on screen after changing to non-native mode for 30 sec

2. For auto input select function, it shall meet the requirement in Appendix D.

3. The OSD should disappear after 10 sec or by pushing button [1] or [2]

Resolution Notice function should be disabled when push button [2] under Resolution Notice OSD

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0-Touch™ Function Actions

1. Execute Auto Image Adjust when new mode detected, and save the settings to buffer for further use

2. It should be reset by Memory Recall function

(Should not reset by power off, power unplug and others)

OSD Auto Save
The OSD shall save new settings when it is turned off by the user or when it times out. There shall not be a separate save

3.4 Factory Defaults

Item Defaults Item Defaults

Contrast 70% Input Priority N/A

Brightness 100% Resolution Notice On

Color Temperature 6500K Volume 50%

Sharpness 100% Balance N/A

OSD H. Position 50% Treble N/A

OSD V. Position 50% Bass N/A

OSD Time Out 15 720x400 / 640x400 (@70Hz) 720x400

OSD Background On 640x480 / 640x400

(@60Hz)

640x480

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3.5 OSD Menu Controls

Select the menu items shown below by using the up [▲] and down [▼] buttons.

 Main Menu :

 Auto Image Adjust :

To automatically adjust H./ V. Position, Phase adjust and Clock adjust.

REMARK: There may need to select “Manual Image Adjust” to optimized Performance for various VGA tolerance.

 Contrast / Brightness :

To adjust the Contrast of the video and the backlight currency.

REMARK: 1. These functions setting can be recalled to default by [Up] + [Dn].

2. These functions should be disabled and setting to default in sRGB Mode.

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 Audio Adjust :

To adjust the audio volume and mute.

 Color Adjust :

To select the color temperature sRGB, 9300°K, 7500°K ,6500°K, 5400°K or user color.

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 Information:

To display the data about Horizontal / Vertical frequency, Pixel clock, Resolution , Model number and Serial No. of the

monitor.

 Manual Image Adjust:

Horizontal Size: To adjust the horizontal pixel clock of the video.
H./V. Position: To adjust the horizontal and vertical position of the video.
Fine Tune: To adjust the delay time of data and clock.
Sharpness: To select the picture sharpness of display.

REMARK: This function is available under Native Resolution Mode.

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 Setup Menu:

Language Select: To select one of eight languages.(English, French, German, Spanish, Italian, Finnish, Japanese,

Traditional Chinese, and Simplified Chinese)

Resolution Notice: Enable (on) : OSD will notify the best picture quality resolution change the resolution to 1280 x

1024.

OSD Position: To set OSD position.
OSD Timeout: To set the displaying time of OSD ( 5” / 15” / 30” / 60” ).
OSD Background: To select video background brightness.

 Memory Recall:

Restore default settings of Clock, H./V. Position, Phase, Contrast, Brightness, Color temperature, OSD position, OSD

timeout and Sharpness, Volume.

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4. Circuit Description

1. Power supply (DC/DC Converter)

This brick convert is the 110-220AC input voltage to 12V AND 5V output for inverter,

audio, panel and system controller use.

It consists of a PWM IC (CM0565R, U101)

2. Scaling controller

The ADC is to convert RGB analog signal to digital signal that scaling chip can

acknowledge.

The HSYNC input receives a logic signal and provides the frequency reference for

pixel clock generation.

The scaling IC is to converts the input signal ranging from VGA to SXGA.

GENERAL DESCRIPTION

The TSUM57AK is a high performance, and fully integrated graphics processing IC solution

for LCD monitors with resolutions up to SXGA. It is configured with an integrated triple-ADC/PLL,

a high quality scaling engine, an on-screen display controller, a built-in output clock generator,

and LVDS display interface. To further reduce system costs, the TSUM57AK also integrates

intelligent power management .

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5. Adjustment Procedure

1. Function Test

1.1 Product

- 19” LCD Monitor

1.2 Test Equipment

- Color Video Signal & Pattern (or PC with SXGA resolution and a sound card)

1.3 Test Condition

Before function test and alignment, each LCD Monitor should be run-in and warmed

up for at least 30 minutes with the following conditions:

(a) In room temperature,

(b) With full-white screen, RGB, and Black

(c) With cycled display modes,

640*480 (H=37.5kHz, V=75Hz)

800*600 (H=46.9kHz, V=75Hz)

1024*768 (H=60kHz, V=75Hz)

1280*1024 (H=80kHz, V=75Hz)

1.4 Test Display Modes & Pattern

1.4.1 Compatible Modes

Analog

1. 640 x 480 @ 60Hz, 31.5kHz

2. 640 x 480 @ 67Hz, 35.0kHz

3. 640 x 480 @ 72Hz, 37.9kHz

4. 640 x 480 @ 75Hz, 37.5kHz

5. 720 x 400 @ 70Hz, 31.5kHz

6. 800 x 600 @ 56Hz, 35.1kHz

7. 800 x 600 @ 60Hz, 37.9kHz

8. 800 x 600 @ 72Hz, 48.1kHz

9. 800 x 600 @ 75Hz, 46.9kHz

10. 832 x 624 @ 75Hz, 49.7kHz

11. 1024 x 768 @ 60Hz, 48.4kHz

12. 1024 x 768 @ 70Hz, 56.5kHz

13. 1024 x 768 @ 75Hz, 60.0kHz

14. 1280 x 1024 @ 60Hz, 64.0kHz

15. 1280 x 1024 @ 75Hz, 80.0kHz

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1.4.2 Function Test Display Pattern

Item Test Content Pattern Specification Remark

1 Frequency &

Tracking

2 Contrast/Brightness 16 Gray Scale 16 gray levels should be

3 Boundary Horizontal &

4 RGB Color

Performance

5 Screen Uniformity

& Flicker

6 Dead Pixel/Line White Screen &

7 White Balance White & Black

Fine Line Moire Eliminate visual wavy

noise.

distinguishable.

Horizontal and Vertical position
Vertical
Thickness
RGB Color
Intensities
Full White Should be compliant with the

Dark Screen

Pattern

of video should be adjustable to

be within the screen frame.

Contrast of each R, G, B, color

should be normal.

spec.

The numbers of dead pixels

should be compliant with the

spec.

The screen must have the pure

white and black pattern, no other

color.

Figure 1

Figure 2

Figure 3

Figure 4, 5,
6
Figure 7

Figure 7, 8

Figure 9

Fine Line Morie Pattern (Figure1) Gray Scale Pattern (Figure2)

Horizontal & Vertical Thickness Pattern

(Figure 3)

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R. Color Pattern (Figure 4)

G. Color Pattern (Figure5) B. Color Pattern (Figure 6)

Full White Patter (Figure 7) Dark Screen Pattern (Figure 8)

Black-White Pattern (Figure 9)

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