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Service Manual
ViewSonic VG720
Model No VS10791
17" Color TFT LCD Display
Manufacture Date: Aug-10-05
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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 manual or otherwise, without the prior written permission of ViewSonic
Corporation.
Disclaimer
ViewSonic makes no representation or warranties, either expressed or implied, with
respect to the contents hereof and specifically disclaims any warranty of merchantability of
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 Date Description of changes Approval
A00 Aug-10-05 Initial Release YG.WANG
Update the Handing and Placing Methods
A01 Dec-28-05 and the Circuit Description and the YG.WANG
Adjustment Procedure
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TABLE OF CONTENTS
1. Precautions And Safety Notices 4
2. Specification 7
3. Front Panel Control And Indicators 10
4. Circuit Description 16
5. Adjustment Procedure 23
6. Troubleshooting Flow Chart 43
7. Recommended Spare Parts List 44
8. Exploded Diagram And Spare Parts List 61
9. Disassemble Process 64
10. Block Diagram 71
11. Schematic Diagram 72
12. PCB Layout Diagram 79
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1. Precautions And Safety Notices
1.1 SAFETY PRECAUTIONS
This monitor is manufactured and tested on a ground principle that a user's safety comes
first. However, improper use or installation may cause damage to the monitor as well as
the user. Carefully go over the following WARNINGS before installing and keep this guide
handy.
WARNINGS
This monitor should be operated only at the correct power sources indicated on the label
on the rear end of the monitor. If you're unsure of the power supply in your residence,
consult you local dealer or power company.
Use only the special power adapter that comes with this monitor for power input.
Do not try to repair the monitor your self as it contains no user-serviceable parts. This
monitor should only be repaired by a qualified technician.
Do not remove the monitor cabinet. There is high-voltage parts inside that may cause
electric shock to human bodies, even when the power cord is unplugged.
Stop using the monitor if the cabinet is damaged. Have it checked by a service technician.
Put your monitor only in a clean, dry environment. If it gets wet, unplug the power cable
immediately and consult your service technician.
Always unplug the monitor before cleaning it .Clean the cabinet with a clean, dry cloth.
Apply non-ammonia based cleaner onto the cloth, not directly onto the glass screen.
Keep the monitor away from magnetic objects, motors, TV sets, and transformer.
Do not place heavy objects on the monitor or power cord.
1.2 PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety visual inspections
and the protection afforded by them cannot necessarily be obtained by using replacement
components rated for higher voltages, wattage, etc. Before replacing any of these
components read the parts list in this manual carefully. The use of substitute replacement
parts which do not have the same safety characteristics as specified in the parts list may
create shock, fire ,or other hazards.
1.3 SERVICE NOTES
1. When replacing parts or circuit boards, clamp the lead wires around terminals before
soldering.
2. When replacing a high wattage resistor(more than 1W of metal oxide film resistor) in
circuit board, keep the resistor about 5mm away from circuit board.
3. Keep wires away from high voltage, high temperature components and sharp edges.
4. Keep wires in their original position so as to reduce interference.
5. Usage of this product please refer to also user's manual.
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1.4 HANDING AND PLACING METHODS
Correct Methods: Incorrect Methods:
Only touch the metal frame of the LCD
Surface of the LCD panel is pressed by fingers
panel or the front cover of the monitor. Do
and that may cause "Mura."
not touch the surface of the polarizer.
Taking out the monitor by grasping the LCD
Take out the monitor with cushions
panel. That may cause "Mura."
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Placing the monitor on foreign objects. That
Place the monitor on a clean and soft foam
could scratch the surface of the panel or cause
pad.
"Mura."
Place the monitor on the lap, the panel The panel is placed facedown on the lap. That
surface must be upwards. may cause "Mura."
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2. Specification
2.1 PRODUCT SPECIFICATIONS
LCD Panel 17.0" TFT
Recommend Resolution 1280 x1024@60Hz
Pixel Dimension 0.264(H) x 0.264(V)mm
LCD Display Color 16.2M Colors (RGB 6-bit+FRC data)
Horizontal: 140 °
Viewing Angle Vertical: 125 °
Contrast Ratio 600 1 (Typ.)
Brightness 270 cd/ (Typ.)
Response Time 8ms(Typ.)
Active Display Area 337.920(H) x 270.336(V)
Maximum Pixel Clock 135 MHz
Horizontal Frequency 30 82 kHz
Vertical Refresh Rate 50 75 Hz.
Operating: 0°C to +40°C
Temperature
Storage: -20°C to +60°C
Energy Star compliant VESA
Power Management DPMS compatible
<1 W
Input Voltage : 90V~264V
Power
Consumption: 48 Watts(Max.) 43 Watts(Typ.)
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2.2 INTERFACE DESCRIPTION
D-SUB 15 PIN CONNECTOR
Pin Number Pin Function
1 Red video input
1 5
6 10 2 Green video input
11 15
3 Blue video input
4 No Connection
5 Ground
6 Red video ground
7 Green video ground
8 Blue video ground
9 +5V
10 H/V sync ground
11 No connection
12 (SDA)
13 Horizontal sync (Composite sync)
14 Vertical sync
15 (SCL)
SIGNAL LEVEL
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DVI-D 24 PIN CONNECTOR
Pin No. Signal Name Description
1 RX2- TMDS negative differential input, channel 2
2 RX2+ TMDS positive differential input, channel 2
3 GND Logic Ground
4 Reserved 4 Reserved. No connection
5 Reserved 5 Reserved. No connection
6 DDC-CLK DDC2B Clock
7 DDC-DAT DDC2B Data
8 Reserved 8 Reserved. No connection
9 RX1- TMDS negative differential input, channel 1
10 RX1+ TMDS positive differential input, channel 1
11 GND Logic Ground
12 Reserved 12 Reserved. No connection
13 Reserved 13 Reserved. No connection
14 VCCX Power
15 GND Logic Ground
16 SENS SENSE Pin, Pull High
17 RX0- TMDS negative differential input, channel 0
18 RX0+ TMDS positive differential input, channel 0
19 GND Logic Ground
20 Reserved 20 Reserved. No connection
21 Reserved 21 Reserved. No connection
22 GND Logic Ground
23 RXC+ TMDS positive differential input, reference clock
24 RXC- TMDS negative differential input, reference clock
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3. Front Panel Function Controls And Indicators
Mute Audio Mute button turns the sound off
Volume+/ Volume- Decreases or increases volume
Button 1 Scrolls through menu options and adjusts the displayed
control. Also a shortcut to display the Contrast adjustment control
screen.
[] [] Displays the control screen for the highlighted control. Also
toggles between two controls on some screens. Also a shortcut to toggle
analog and digital connection.
Button 2 Displays the control screen for the highlighted control. Also toggles
between two controls on some screens. Also a shortcut to toggle analog and
digital connection.
Power Standby Power On/Off
Green ON
Power LED (Front Head) Orange Active Off
Dark = Soft Power Switch OFF
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Do the following to adjust the display setting:
1. To display the Main Menu, press button [1].
NOTE: All OSD menus and adjustment screens disappear automatically after about 15
seconds. This is adjustable through the OSD timeout setting in the setup menu.
2. To select a control to adjust, press or to scroll up or down in the Main Menu.
3. After the desired control is selected, press button [2]. A control screen like the one
shown below appears.
The command line at the bottom of the control
screen tells what to do next from this screen.
You can toggle between control screens,
adjust the selected option, or exit the screen.
4. To adjust the setting, press the up or down T buttons.
5. To save the adjustments and exit the menu, press button [1] twice.
The following tips may help you optimize your display:
· Adjust the computer's graphics card so that it outputs a 1280 x 1024 @ 60Hz video
signal to the LCD display. (Look for instructions on "changing the refresh rate" in the
graphics card's user guide.)
· If necessary, make small adjustments using H. POSITION and V. POSITION until the
screen image is completely visible. (The black border around the edge of the screen
should barely touch the illuminated "active area" of the LCD display.)
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Main Menu Controls
Adjust the menu items shown below by using the up and down buttons.
Control Explanation
Auto Image Adjust sizes and centers the screen image automatically.
Contrast adjusts the difference between the image background (black level)
and the foreground (white level).
Brightness adjusts background black level of the screen image.
Input Select allows the user to toggle between an analog and a digital signal.
Audio Adjust
Volume increases the volume, decreases the volume, and mutes the audio.
Mute temporarily silences audio output.
Color Adjust provides several color adjustment modes, including preset color
temperatures and a User Color mode which allows independent adjustment of
red (R), green (G), and blue (B). The factory setting for this product is 6500K
(6500 Kelvin).
9300K-Adds blue to the screen image for cooler white (used in most office
settings with fluorescent lighting).
6500K-Adds red to the screen image for warmer white and richer red.
5400K-Adds green to the screen image for a darker color.
User Color Individual adjustments for red (R), green (G), and blue (B).
1. To select color (R, G or B) press button [2].
2. To adjust selected color, press and .
Important: If you select RECALL from the Main Menu when the product is
set to a Preset Timing Mode, colors return to the 6500K factory preset.
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Information displays the timing mode (video signal input) coming from the
graphics card in the computer, the LCD model number, the serial number, and
®
the ViewSonic website URL. See your graphics card's user guide for
instructions on changing the resolution and refresh rate (vertical frequency).
NOTE: VESA 1280 x 1024 @ 60Hz (recommended) means that the resolution
is 1280 x 1024 and the refresh rate is 60 Hertz.
Manual Image Adjust Sub-menu
H. Size (Horizontal Size) adjusts the width of the screen image.
H./V. Position (Horizontal/Vertical Position) moves the screen image left or
right and up or down.
Fine Tune sharpens the focus by aligning text and/or graphics with pixel
boundaries.
NOTE: Try Auto Image Adjust first.
Sharpness adjusts the clarity and focus of the screen image.
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Setup Menu displays the menu shown below:
Language Select allows the user to choose the language used in the menus
and control screens.
Resolution Notice allows the user to enable or disable this notice.
If you enable the Resolution Notice shown above and your computer is set at
a resolution other than 1280 x 1024, the following screen appears.
OSD Position allows the user to move the OSD menus and control screens.
OSD Timeout sets the length of time the OSD screen is displayed. For
example, with a "30 second" setting, if a control is not pushed within 30
seconds, the display screen disappears.
OSD Background allows the user to turn the OSD background On or Off.
Memory Recall returns the adjustments back to factory settings if the display
is operating in a factory Preset Timing Mode listed in the Specifications of this
manual.
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SHORT CUTS FUNCTION FROM THE BUTTONS
[1] Main Menu
[2] Input toggle (Analog or Digital).
To immediately activate Contrast menu. It should be
[] or []
change to Brightness OSD by push button [2]
[] + [] recall both of Contrast and Brightness to default
[ +] or [ -] To immediately activate Volume menu for audio volume.
[ +] + [ X] Recall volume to default
toggle 720x400 and 640x400 mode when input 720x400
[1] + [2]
or 640x400 mode
[1] + [ X] White Balance. (Not shown on user's guide)
· Power Button Lock: Press and hold "[2], & " for 10
seconds. If the power button is pressed the message
Power Button Locked will display for 5 seconds. With or
without this setting, after a power failure, your LCD
[2] + []
display's power will automatically turn ON when power is
restored.
· Power Button Unlock: Press and hold "[2], & " again
for 10 seconds.
· OSD Lock: Press and hold "[1], & ()" for 10 seconds.
If any buttons are pressed the message OSD Locked will
[1] + [] display for 5 seconds.
· OSD Unlock: Press and hold "[1], & " again for 10
seconds.
Remark : All the short cuts function are only available while OSD off
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4. Circuit Description
4.1 LCD MONITOR DESCRIPTION
The LCD MONITOR will contain a Main Board, an Power Board, Key Board which
house the flat panel control logic, brightness control logic and DDC.
Monitor Block Diagram
CCFL Drive. Flat Panel and
CCFL backlight
RS232 Connector
Power Board Main Board
For white balance
(Include: adapter, inverter)
adjustment in factory
mode
Video signal, DDC
Key Board
AC-IN HOST Computer
100V-240V
4.2 MAIN BOARD BLOCK FUNCTION DESCRIPTION
The main board contains panel control logic, brightness control logic, DDC and DC
convert DC circuit and so on.
PWPC board
R
G
B
H Backlight and Panel
V TSUM56AK
SDA
SCL
OSC
Keyboard
EPROM EPROM
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4.3 PWPC BOARD BLOCK FUNCTION DESCRIPTION
PWPC board combines to adapter and inverter, Adapter which commonly consists
of bridge rectifier and filter, start circuit, PWM control circuit, protection circuits and
convert to 12V, 5V DC voltage by input 90V-240V AC voltage that provide power supply
for each chips in the main board and inverter. Inverter is DC TO AC circuit. It changes
the 12v DC of power supply to about 600-800v AC that drives the backlight. It mostly
consists of starting circuit, PWM controller, DC changing circuit, LC surging circuit,
output circuit and protection circuit etc.
Bridge Rectifier
AC input Transformer
EMI filter Rectifier CMOS
and Filter
Start Circuit
R903, R904,R905 CN902
5V
PWM Over 12V
Control IC Voltage
Protect
ON/OF
OSC and MOSFET
Output DC Convert
Circuit Q203
Circuit
Lamp
Feedback Over ON/OFF
Circuit Voltage PWM Control
Control IC
DIM
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4.4 INTRODUCTION OF IC
STUM56AK(U401): integrate ADC, OSD, SCALER, MCU, LVDS, convert analog RGB
into digital and room and shrink scaling output to LCD panel.
PIN Function:
Pin Symbol Description
70 SDO SPI flash serial data output; Input w/5V-tolerant
71 CSZ SPI flash chip select; output
72 SCK SPI flash serial select; output
73 SDI SPI flash serial data input; output
65 DDCA_SDA/RS232_TX DDC data for analog interface; 4mA driving
strength/UART transmitter/GPIO; I/O w/5V-tolrant
66 DDCA_SDA/RS232_RX DDC data for analog interface/UART
transmitter/GPIO;Input w/5V-tolrant
36 DDCD_SDA DDC data for DVI interface; 4mA driving strength;
I/O w/5V-tolerant
37 DDCD_SCL DDC clock for DVI interface; Input w/5V-tolerant
19 RST Chip reset; High reset; Input w/5V-tolerant
22 RSTN Chip reset; Low reset; Input w/5W-toerant
11 VCTRL Regulator control; Output
63 HSYNCO Analog HSYNC input
64 VSYNCO Analog VSYNC input
62 REFP Internal ADC top de-coupling pin
61 REFM Internal ADC bottom de-coupling pin
51 REXT External resistor 390 ohm to AVDD DVI
21 PWM1 PWM1; 4mA driving strength; Output
29 PWM0 PWM0; 4mA driving strength; Output
4 BYPASS For External Bypass Capacitor
33 XIN Xin; Crystal Oscillator Input
34 XOUT Xout; Crystal Oscillator Output
44 50 AVDD DVI DVI Power 3.3V
60 AVDD ADC ADC Power 3.3V
52 AVDD PLL PLL Power 3.3V
34 AVDD MPLL MPLL Power 3.3V
14 67 95
VDDP Digital Output Power 3.3V
103 115
13 38 41 VDDC Digital Core Power 1.8V
47 96 116
AIC1084-33PM (U702): DC power convert, used to 5v convert 3.3v.
LT1117-18(U701): DC power convert, used to 5v convert 3.3v.
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TPA3003D2 (U601): The TPA3003D2 is a audio amplifier IC,3-W efficient, driving
speakers as low as 8 , range of gain from -40dB to 36 dB. The function of
each pin and the inside circuit diagram are as follows:
Circuit Diagram
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PIN Function
TERMINAL
I/O DESCRIPTION
NO. NAME
AGND 9,10,26 - Analog ground for digital/analog cells in core
AVcc 33 - High-voltage analog power supply (8.5V to 14V)
AVDD 29 O 5-V Regulated output
AVDDREF 7 O 5-V Reference output-provided for connection to adjacent VREF terminal.
BSLN 13 I/O Bootstrap I/O for left channel, negative high-side FET
BSLP 24 I/O Bootstrap I/O for left channel, positive high-side FET
BSRN 48 I/O Bootstrap I/O for right channel, negative high-side FET
BSRP 37 I/O Bootstrap I/O for right channel, positive high-side FET
I/O for charge/discharging currents onto capacitor for ramp generator triangle wave
COSC 28 I/O biased at V2P5
Input for controlling volume ramp rate when cycling SD or during power-up. A logic
FADE 30 I low on this pin places the amplifier in fade mode. A logic
high on this pin allows a quick transition to the desired volume setting.
LINN 6 I Negative differential audio input for left channel
LINP 5 I Positive differential audio input for left channel
LOUTN 16,17 O Class-D 1/2-H-bridge negative output for left channel
LOUTP 20,21 O Class-D 1/2-H-bridge positive output for left channel
MUTE 34 I A logic high on this pin disables the outputs. A low on this pin enables the outputs.
NC 31,32,35 - Not internally connected
PGNDL 18,19 - Power ground for left channel H-bridge
PGNDR 42,43 - Power ground for right channel H-bridge
Power supply for left channel H-bridge(tied to pins 22 and 23 internally), not
PVVCCL 14,15 - connected to PVCCR or AVcc
Power supply for left channel H-bridge(tied to pins 14 and 15 internally), not
PVVCCL 22,23 - connected to PVCCR or AVcc
Power supply for right channel H-bridge(tied to pins 46 and 47 internally), not
PVCCR 38,39 - connected to PVCCL or AVcc
Power supply for right channel H-bridge(tied to pins 38 and 39 internally), not
PVCCR 46,47 - connected to PVCCL or AVcc
Ground for gain control circuitry. Connect to AGND. If using a DAC to control the
REFGND 12 - volume, connect the DAC ground to this terminal.
RINP 3 I Positive differential audio input for right channel
RINN 2 I Negative differential audio input for right channel
ROSC 27 I/O Current setting resistor for ramp generator. Nominally equal to 1/8*Vcc
ROUTN 44,45 O Class-D 1/2-H-bridge negative output for right channel
ROUTP 40,41 O Class-D 1/2-H-bridge positive output for right channel
Shutdown signal for IC (low=shutdown, high=operational). TTL logic levels with
SD 1 I compliance to Vcc.
VCLAMPL 25 - Internally generated voltage supply for left channel bootstrap capacitors.
VCLAMPR 36 - Internally generated voltage supply for right channel bootstrap capacitors.
VOLUME 11 I DC voltage that sets the gain of the amplifier.
VREF 8 I Analog reference for gain control section.
2.5-V Reference for analog cells, as well as reference for unused audio input when
V2P5 4 O using single-ended inputs.
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NCP1203D60R2G (IC901): PWM control, high-voltage startup current. The circuit unit
has functions such as over-current protection, over-voltage protection, output
short-circuit protection and etc. The function of each pin and the inside circuit diagram
are as follows:
Pin Pin
Function Pin Description
No. Name
This pin lets you adjust the level at which the cycle
Adjust the skipping
1 Adj skipping process takes place. Shorting this pin to ground,
peak current
permanently disables the skip cycle feature.
By connecting an optocoupler to this pin, the peak current
Sets the peak
2 FB setpoint is adjusted accordingly to the output power
current setpoint
demand. Skip cycle occurs when FB falls below Vpin1.
This pin senses the primary current and routes it to the
3 CS Current sense input
internal comparator via an L.E.B.
4 GND The IC ground -
5 Drv Driving pulses The driver's output to an external MOSFET.
This pin is connected to an external bulk capacitor of
6 VCC Supplies the IC
typically 22 F.
This unconnected pin ensures adequate creepage
7 NC -
distance.
Ensure a clean and Connected to the high-voltage rail, this pin injects a
8 HV lossless startup constant current into the VCC capacitor during the startup
sequence sequence.
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TL1451 (IC201): PWM control, voltage range for working: 3.6~35V, Has such functions
as short-voltage protection, Over-voltage protection, over-current protection and
etc. The function of each pin and the circuit diagram inside are as follows:
Pin Symbol Description Pin Symbol Description
1 CT External timing capacitor 9 VCC Power supply
2 RT External timing resistor 10 2OUT Output 2
3 1IN+ Positive input for error amplifier 1 11 2DTC Output 2 dead time/soft start setting
4 1IN- Positive input for error amplifier 2 12 2FBK Error amplifier 2 output
5 1FBK Error amplifier 1 output 13 2IN+ Positive input for error amplifier
Output 1 dead time/soft start
6 1DTC 14 2IN- Positive input for error amplifier
setting
7 1OUT Output 1 15 SCP Timing latch setting
8 GND Ground 16 REF Reference voltage output (2.5v)
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5. Adjustment Procedure
5.1 ADJUSTMENT CONDITIONS AND PRECAUTIONS
1. Approximately 30 minutes should be allowed for warm up before proceeding.
2. Adjustments should be undertaken only on those necessary elements since most of them
have been carefully preset at the factory.
3. ESD protection is needed before adjustment.
5.2 MAIN ADJUSTMENTS
NO. FUNCTIONS DESIGNATION
1. White Balance Function Key
2. Geometry Function Key
5.3 ALIGNMENT PROCEDURES
Approximately 30 minutes should be allowed for warm up before proceeding
White-Balance adjustment.
1. Adjust of White Balance
1.)How to do the Chroma-7120 MEM .Channel setting
A Reference to chroma 7120 user guide
B Use " SC" key and " NEXT" key to modify xyY value and use "ID" key to modify the
TEXT description Following is the procedure to do white-balance adjust
2.)Setting the color temp. You want
A MEM.CHANNEL9 ( 9300 color):
9300 color temp. parameter is Wx = 0.283 0.03;Wy = 0.298 0.03;
Y = 250 20 cd/m2 ,
B MEM.CHANNEL10 ( 6500 color):
6500 color temp. parameter is Wx = 0.313 0.03;Wy = 0.329 0.03;
Y = 260 20 cd/m2,
C MEM.CHANNEL 11 ( 5400 color):
5400 color temp. parameter is Wx = 0.335 0.03;Wy = 0.350 0.03;
Y = 250 20 cd/m2,
D MEM.CHANNEL10 ( SRGB color):
6500 color temp. parameter is Wx = 0.313 0.03;Wy = 0.329 0.03;
Y = 220 20 cd/m2,
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3.)Into factory mode of VG720
A First Power off, then press Switch 2 button along with press Power button will activate
the factory mode, then MCU will do AUTO LEVEL automatically. Meanwhile press
MENU the OSD screen will located at LEFT TOP OF PANEL.
4.)Bias adjustment :
Set the Contrast to 70
Adjust the Brightness to 100.
5.)Gain adjustment :
Move cursor to "-F-" and press MENU key
A Adjust 9300 color-temperature
(1) Switch the Chroma-7120 to RGB-Mode (with press "MODE" button )
(2) Switch the MEM. channel to Channel 9 ( with up or down arrow on chroma 7120 )
(3) The LCD-indicator on chroma 7120 will show x = 0.283 0.03, y =0.298 0.03,
Y = 250 20 cd/m2
(4) Adjust the RED of color1 on factory window until chroma 7120 indicator reached
the value R=100
(5) Adjust the GREEN of color1 on factory window until chroma 7120 indicator reached
the value G=100
(6) Adjust the BLUE of color1 on factory window until chroma 7120 indicator reached
the value B=100
(7) Repeat above procedure ( item 4,5,6) until chroma 7120 RGB value meet the
tolerance =100 5
B Adjust 6500 color-temperature
(1) Switch the chroma-7120 to RGB-Mode (with press "MODE" button )
(2) Switch the MEM .channel to Channel 10( with up or down arrow on chroma 7120 )
(3) The LCD-indicator on chroma 7120 will show x = 0.313 0.03, y = 0.329 0.03, Y =
260 20 cd/m2
(4) Adjust the RED of color3 on factory window until chroma 7120 indicator reached
the value R=100
(5) Adjust the GREEN of color3 on factory window until chroma 7120 indicator reached
the value G=100
(6) Adjust the BLUE of color3 on factory window until chroma 7120 indicator reached
the value B=100
(7) Repeat above procedure ( item 4,5,6) until chroma 7120 RGB value meet the
tolerance =100 5
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C Adjust 5400 color-temperature
(1) Switch the chroma-7120 to RGB-Mode (with press "MODE" button )
(2) Switch the MEM .channel to Channel 11( with up or down arrow on chroma 7120 )
(3) The LCD-indicator on chroma 7120 will show x = 0.335 0.03, y = 0.350 0.03, Y =
250 20 cd/m2
(4) Adjust the RED of color3 on factory window until chroma 7120 indicator reached the
value R=100
(5) Adjust the GREEN of color3 on factory window until chroma 7120 indicator reached
the value G=100
(6) Adjust the BLUE of color3 on factory window until chroma 7120 indicator reached
the value B=100
(7) Repeat above procedure ( item 4,5,6) until chroma 7120 RGB value meet the
tolerance =100 5
D Adjust SRGB color-temperature
(1) Switch the chroma-7120 to RGB-Mode (with press "MODE" button )
(2) Switch the MEM .channel to Channel 10( with up or down arrow on chroma 7120 )
(3) The LCD-indicator on chroma 7120 will show x = 0.313 0.03, y = 0.329 0.03, Y =
220 20 cd/m2
(4) Adjust the RED of color3 on factory window until chroma 7120 indicator reached
the value R=100
(5) Adjust the GREEN of color3 on factory window until chroma 7120 indicator reached
the value G=100
(6) Adjust the BLUE of color3 on factory window until chroma 7120 indicator reached
the value B=100
(7) Repeat above procedure ( item 4,5,6) until chroma 7120 RGB value meet the
tolerance =100 5
E Press reset key and Turn the Power-button "off to on" to quit from factory mode.
2. Geometry
1).Set cross-hatch pattern and preset timing as timing table listed.
2).Change to each mode in turn and wait for the monitor finish auto-alignment and save
press before change to next mode.
3).Until all of modes are adjusted,exit OSD menu and press POWER OFF to exit factory
mode.
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5.4 Factory Defaults
Item Defaults Item Defaults
Contrast 70% Sharpness 33%
Brightness 100% OSD H. Position 50%
Volume 50% OSD V. Position 50%
Balance 50% OSD Time Out 15 Sec
Bass 50% OSD Background On
Treble 50% OSD PIVOT Off
Color Temperature 6500K Resolution Notice Enabled
720x400/640x400 720x400
5.5 Function Test
1 Product: 17" LCD Monitor
2 Test Equipment: Color Video Signal & Pattern (or PC with SXGA resolution and a
sound card)
3 Test Condition: Before function test and alignment, each LCD Monitor should be
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=43.27kHz, V=85Hz)
800*600 (H=53.7kHz, V=85Hz)
1024*768 (H=68.67kHz, V=85Hz)
1280*1024 (H=79.97kHz, V=75Hz)
4 Test Display Modes & Pattern
Compatible Modes
Analog Digital
640 x 350 @ 70Hz, 31.5kHz 640 x 350 @ 70Hz, 31.5kHz
640 x 400 @ 70Hz, 31.5kHz 640 x 400 @ 70Hz, 31.5kHz
640 x 480 @ 60Hz, 31.5kHz 640 x 480 @ 60Hz, 31.5kHz
640 x 480 @ 67Hz, 35.0kHz 640 x 480 @ 67Hz, 35.0kHz
640 x 480 @ 72Hz, 37.9kHz 640 x 480 @ 72Hz, 37.9kHz
640 x 480 @ 75Hz, 37.5kHz 640 x 480 @ 75Hz, 37.5kHz
720 x 400 @ 70Hz, 31.5kHz 720 x 400 @ 70Hz, 31.5kHz
800 x 600 @ 56Hz, 35.1kHz 800 x 600 @ 56Hz, 35.1kHz
800 x 600 @ 60Hz, 37.9kHz 800 x 600 @ 60Hz, 37.9kHz
800 x 600 @ 75Hz, 46.9kHz 800 x 600 @ 75Hz, 46.9kHz
800 x 600 @ 72Hz, 48.1kHz 800 x 600 @ 72Hz, 48.1kHz
832 x 624 @ 75Hz, 49.7kHz 832 x 624 @ 75Hz, 49.7kHz
1024 x 768 @ 60Hz, 48.4kHz 1024 x 768 @ 60Hz, 48.4kHz
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1024 x 768 @ 70Hz, 56.5kHz 1024 x 768 @ 70Hz, 56.5kHz
1024 x 768 @ 72Hz, 58.1kHz 1024 x 768 @ 72Hz, 58.1kHz
1024 x 768 @ 75Hz, 60.0kHz 1024 x 768 @ 75Hz, 60.0kHz
1280 x 1024 @ 60Hz, 63.4kHz 1280 x 1024 @ 60Hz, 63.4kHz
1280 x 1024 @ 75Hz, 79.97kHz 1280 x 1024 @ 75Hz, 79.97kHz
1280x 720 @ 60Hz, 45kHz 1280x 720 @ 60Hz, 45kHz
Function Test Display Pattern
Item Test Content Pattern Specification Remark
Frequency & Eliminate visual wavy
1 Fine Line Moire Figure 1
Tracking noise.
Contrast/Bright 16 gray levels sh should
2 16 Gray Scale Figure 2
ness be distinguishable.
Horizontal and Vertical
Horizontal&Vertical position of video should
3 Boundary Figure 3
Thickness be adjustable to be
within the screen frame.
Contrast of each R, G,
RGB Color Figure
4 RGB Color Intensities B, color should be
Performance 4,5,6
normal.
Screen
Should be compliant
5 Uniformity & Full White Figure 7
with the spec.
Flicker
The numbers of dead
Dead White Screen & Dark
6 pixels should be Figure 7,8
Pixel/Line Screen
compliant with the spec.
The screen must have
7 White Balance White & Black Pattern the pure white and black Figure 9
pattern, no other color.
Fine Line Morie Pattern (Figure1) Gray Scale Pattern (Figure2)
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Horizontal & Vertical Thickness Pattern R. Color Pattern (Figure 4)
(Figure 3)
G. Color Pattern (Figure 5) B. Color Pattern (Figure 6)
Full White Pattern (Figure 7) Dark Screen Pattern (Figure 8)
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Black-White Pattern (Figure 9)
4.3 Function Test and Alignment Procedure
All Modes Reset
You should do "All Mode Reset" (Refer to Chapter III-3. Hot Keys for Function
Controls) first. This action will allow you to erase all end-user's settings and restore
the factory defaults.
Auto Image Adjust
Please select and enter "Auto Image Adjust" function on Main Menu to see if it is
workable. The "Auto Image Adjust" function is aimed to offer a better screen quality
by built-in ASIC. For optimum screen quality, the user has to adjust each function
manually.
Firmware
Test Pattern: Burn In Mode (Refer to Chapter III-3. Hot Keys for Function Controls)
- Make sure the F/W is the latest version.
DDC
Test Pattern: EDID program
Make sure it can pass test program.
Fine Tune and Sharpness
Test Signal: 1280*1024@60Hz
Test Pattern: Line Moire Pattern
Check and see if the image has noise and focus performs well. Eliminate visual
line bar.
If not, readjust by the following steps:
(a)Select and enter "Fine Tune" function on "Manual Image Adjust" to adjust the
image to eliminate visual wavy noise.
(b)Then, select and enter "Sharpness" function to adjust the clarity and focus of
the screen image.
Boundary
Test Signal: 1280*1024@60Hz
Test Pattern: Horizontal & Vertical Line Thickness Pattern
Check and see if the image boundary is within the screen frame.
If not, readjust by the following steps:
(a)Select and enter "Manual Image Adjust" function on OSD Main Menu.
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(b)Then, select and enter "Horizontal Size" or "Horizontal/Vertical Position" function
to adjust the video boundary to be full scanned and within screen frame.
White Balance
Test Signal: 640*480@60Hz
Test Pattern: White and Black Pattern
1.5.8 R, G, B, Colors Contrast
Test Signal: 1280*1024@60Hz
Test Pattern: R, G, B, Color Intensities Pattern and 16 Gray Scale Pattern
- Check and see if each color is normal and distinguishable.
- If not, please return the unit to repair area.
Screen Uniformity and Flicker
Test Signal: 1280*1024@60Hz
Test Pattern: Full White Pattern
- Check and see if it is in normal condition.
1.5.10 Dead Pixel and Line
Test Signal: 1280*1024@60Hz
Test Pattern: Dark and White Screen Pattern
- Check and see if there are dead pixels on LCD panel with shadow gauge and
filter film.
- The total numbers and distance of dead pixels should be compliant with the
spec.
Mura
Test Pattern: White, RGB, Black, & Grey
Test Tool: 10% ND Filter
- Check if the Mura can pass 10% ND Filter.
Audio
Test Signal: Voice signal (optional, depend on model)
Test Pattern: liberty
- Make sure there is audio output.
- Make sure that audio function (volume 80%) is working without noise and
resonance.
- Make sure that the sound of right and left speakers are in balance.
Check for Secondary Display Modes
Test Signal:
Analog: 640*350@70Hz; 640*480@60/67/72/75/85Hz;
720*400@70Hz; 800*600@56/60/72/75/85Hz;
832*624@75Hz, 1024*768@60/70/72/75/85Hz;
1280*1024@60/75Hz
Digital: 640*350@70Hz; 640*480@60/72/75/85Hz;
720*400@70Hz; 800*600@56/60/72/75/85Hz;
1024*768@60/70/72/75/85Hz; 1152*870@75Hz,
1280*720@60Hz, 1280*1024@60Hz
- Normally when the primary mode 1280*1024@60Hz is well adjusted and
compliant with the specification, the secondary display modes will also be
compliant with the spec. But we still have to check with the general test pattern to
make sure every secondary is compliant with the specification.
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All Modes Reset
After final QC step, we have to erase all saved changes again and restore the
factory defaults. You should do "All Mode Reset" again.
Power Off Monitor
Turn off the monitor by pressing "Power" button.
5.6 Firmware Upgrade Procedure
When you receive the returned monitor, please check whether the firmware version is
the latest. If not, please do the following procedures to upgrade it to the latest version.
1 Equipment Needed
- VG720/VG920 Monitor
- Fixture for Firmware Upgrade
- Power Adapter (P/N: 47.58201.001) *1 for Fixture
- VGA Cable (P/N: 42.59901.003) *1(Pin 4, 11 should be connected to GND)
- PC (Personal Computer)
- LPT Cable (P/N: 42.59906.001) *1
- Firmware Upgrade Program
- One additional monitor for checking the program execution
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2 Setup Procedure
2.1 Connect P2 of Fixture with printer port of PC by LPT Cable.
2.2 Connect P1 of Fixture with VG720/VG920 Monitor by VGA Cable.
2.3 Plug Power Adapter to Fixture.
2.4 Connect Power Cord to VG720/VG920 Monitor.
2.5 Connect P3 to the Signal Generator (eg.Chroma2326) for verifying it after the
operation being completed.
2.6 Connect PC to the additional monitor.
JP1 to Power Adapter
P1 to VGA Cable
P3 to Signal Generator
P2 to LPT Cable
3 Firmware Upgrade Procedure
Step 1. Let VG720/VG920 set to be connected with AC cable and VGA cable.
Step 2.Execute the MSstar ISP tool.
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Step 3. Click "Config" button . Select the Port Type: LPT1 and the Base Addr : 0x378
on "Communication Setting" flame,and then the Speed: 47 on "E2PROM Device
Setting" flame
Step 4. Click "Connect" button. (On this step, if the connection is successful, the "Entry
ISP Mode" Dialog will be showed. If not, the error dialog will be done.)
Step 5. Click "Device" button. Select the "PMC25LV010" or "SST25VF010" viewed on
your set.
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Step 6. Click "Read" button. Select the object bincode on your corresponding directory.
Step 7. Click "Auto" button. Execute the flashing action by clicking the "Run" button.
Step 8. If the flashing F/W has been completed, "Ok" message will be showed on the
right TextBox.
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Step 9. Unplug and replug power cord of VG720/VG920 set and then check the OSD
operation and image on srceen.
Step 10. At last, do "Memory Recall."
3.2 Setup Procedure
3.2.1 Connect P2 and P4 of Fixture with VGA ports of VG720 VG720/VG920by VGA
Cable.
3.2.2 Connect P3 of Fixture with DVI port of VG720 by DVI-DVI Cable.
3.2.3 Connect P1 of Fixture with Printer port of PC by LPT Cable.
3.2.4 Plug Power Adapter to Fixture.
3.2.5 Connect Power Cord to VG720/VG920 Monitor.
3.2.6 Connect PC to the additional monitor.
JP1 Power Adapter
P3 DVI-DVI Cable
P2 VGA Cable
P1 to LTP Cable
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3.3 DDC Key In Procedure
Sep1.Select and execute DDc Key In program
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Sep2:Inpute the S/N and execute "Enter"
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Sep3:Key the "Enter" and write the data
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Sep4:If ddc program OK and show "data compare ok"
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5.7 Packing For Shipping
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Packing Part List
ITEM DESCRIPITON PART NUMBER Q'TY
1 CARTON C 44G3778709 1A 1
HANDLE1 50G 600 2 1
2
HANDLE2 50G 600 3 1
3 PE BAG 45G 76 28 V3 1
4 CD MANUAL 70G1701709 5B 1
5 QSG 41G7801709 4A 1
6 EPE COVER 45G 88609 4 1
7 MONITOR T780KQ6HKGVWABP 1
8 EPE COVER 45G 88609 B 1
9 PE BAG 45G 88607 1
44G3778 1 1
10 EPS
44G3778 2 1
11 AUDIO CABLE 89G 173 56507 1
12 POWER CORD 89G402A18N LS 1
13 SIGNAL CABLE 89G 728GAA902 1
14 DVI CABLE 89G1748GAA 11 1
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6. Troubleshooting Flow Chart
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7. Recommended Spare Part List VG720 BOM list T780KQ6HKGVWABP
ViewSonic Universal
Item Ref. P/N Description Location Q'ty
P/N number#
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8. Exploded Diagram And Spare Parts List
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9. Disassemble Process
9.1 Units Disassemble Process
Tools
Glove
Big cross screwdriver
Small cross screwdriver
Prize equipment or abandoned IC card
Screw box
Cushion
Six angle sleeve spanner
9.1.2 Disassemble process
1 Tide up the worktable, spread straight cushion, put the monitor on it, the front side
adown.(Picture 1)
2 Disassemble the 4 screws that fix the stand, remove the stand..(Picture 2, 3, 4)
3 Disassemble the 2 screws of the back cover. Picture 5
4 Use equipment or abandoned IC card to prize up the bezel through the bottom flute,
as showed in the following the picture 6, and rip up the back cover downwards.( as
showed in the following the picture 7,8)
5 Disassemble the 6 screw M3*6MM through six angle sleeve spanner, showed in the
following picture 9.
6 Disassemble the 2 fixed screws in the shield, remove the shield as the direction
arrowhead showed, refer to the following picture ,10.
7 Disassemble the 5 screws and 4 pins of the PWPC board, remove the PWPC
board.(symbolized the following picture 11 with red color)
8 Disassemble the 3 screws and 3 pins of the main board, remove the main board.
(symbolized the following picture 11 with blue color)
9 Disassemble the 2 screws of the audio board, remove the audio board. (symbolized
the following picture 11,12 with yellow color)
10 Disassemble the 4 screws of the speaker, remove the speaker, refer to the following
picture 13
11 Disassemble the 4 fixed screws of the main frame, as showed in the following the
picture 14
12 Disassemble the connect pins of the key board, as showed in the following the
picture 15. remove the bezel as the direction arrowhead showed, refer to the
following picture ,16,17.
13 Disassemble the 4 fixed screws of the panel, remove the main frame, as showed in
the following the picture 18,19. Do not damage the cable of the panel.
14 That's all. The disassemble process of the unit is over.
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9.1.3 Show pictures
Picture 1 Picture 2
Picture 3 Picture 4
Picture 5 Picture 6
Picture 7 Picture 8
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Picture 9 Picture 10
Picture 11
Picture 12 Picture 13
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Picture 14 Picture 15
Picture 16 Picture 17
Picture 18
Picture 19
Picture 20
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9.2 Stand A'ssy Disassemble Process
Picture 1 Picture 2
Picture 3 Picture 4
Picture 5 Picture 6
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Picture 7 Picture 8
Picture 9 Picture 10
Picture 11