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VA703B-1
Service Manual
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Service Manual
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Viewsonic VA703B-1, VA703M-1, VA703M- 2, VA703M- 3, VA703M -4 Service Manual

Service Manual
ViewSonic VA703b-1
VA703m-1
Model No. VS11280
17” Color TFT LCD Display
(VA703b-1_VA703m-1_SM Rev. 1b Oct. 2006)
ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583
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
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 7/28/2006 Initial Release Jamie C.
1b 10/24/2006 VS-E060297 Add 2nd panel source (CPT) Jamie C.
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TABLE OF CONTENTS
1. Precautions and Safety Notices 1
2. Specification 4
3. Front Panel Function Control Description 6
4. Circuit Description 12
5. Adjustment Procedure 20
6. Troubleshooting Flow Chart 44
7. Recommended Spare Parts List 45
8. Exploded Diagram and Exploded Parts List 49
9. Block Diagram 53
10. Schematic Diagrams 54
11. PCB Layout Diagrams 63
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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 panel or the front cover of the monitor. Do not touch the surface of the polarizer.
Surface of the LCD panel is pressed by fingers and that may cause “Mura.”
Take out the monitor with cushions
Taking out the monitor by grasping the LCD panel. That may cause “Mura.”
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Place the monitor on a clean and soft foam pad.
Place the monitor on the lap, the panel surface must be upwards.
Placing the monitor on foreign objects. That could scratch the surface of the panel or cause “Mura.”
The panel is placed facedown on the lap. That may cause “Mura.”
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2. Specification
2.1 PRODUCT SPECIFICATIONS
LCD Panel 17.0” TFT
Recommend Resolution 1280 x 1024@60Hz
Pixel Dimension 0.264(H) x 0.264(V)mm
LCD Display Color 16.2M Colors (6+2bit panel)
Viewing Angle
Contrast Ratio 700：1 (Typ.)
Brightness 300 cd/㎡(Typ.)
Response Time 8ms(Typ.)
Active Display Area 337.92mm(H) x 270.336mm(V)
Maximum Pixel Clock 135 MHz
Horizontal Frequency 30 – 82 kHz
Vertical Refresh Rate 50 – 85 Hz.
Temperature
Power Management
Horizontal: 150 Vertical: 135 °
Operating: 0°C to +40°C Storage: -20°C to +60°C
Energy Star compliant VESA DPMS compatible <1 W
°
Input Voltage : 100V~240V
Power
Consumption: ON Mode < 35 W (max)
POWER SAVING < 2W OFF < 1W
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2.2 INTERFACE DESCRIPTION
D-SUB 15 PIN CONNECTOR
15
6
11 15
10
SIGNAL LEVEL
Pin Number Pin Function
1 Red video input
2 Green video input
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)
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3. Front Panel Function Control Description
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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 line at the bottom of the screen shows the current functions of buttons 1 and 2: Exit or select the Brightness control.
4. To adjust the control, 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 1024 x 768 @ 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 should barely touch the illuminated “active area” of the LCD display.)
. (The black border around the edge of the screen
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Main Menu Controls
Adjust the menu items shown below by using the up S and down T buttons.
Control Explanation
Auto Image Adjust automatically sizes, centers, and fine tunes the video signal to eliminate waviness and distortion. Press the [2] button to obtain a sharper image.
NOTE: Auto Image Adjust works with most common video cards. If this function does not work on your LCD display, then lower the video refresh rate to 60 Hz and set the resolution to its pre-set value.
Contrast adjusts the difference between the image background (black level) and the foreground (white level).
Brightness adjusts background black level of the screen image.
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).
sRGB-This is quickly becoming the industry standard for color management, with support being included in many of the latest applications. Enabling this setting allows the LCD display to more accurately display colors the way they were originally intended. Enabling the sRGB setting will cause the Contrast and Brightness adjustments to be disabled.
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.
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Control Explanation
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, pressSandT.
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.
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 displays the Manual Image Adjust 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.
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Control Explanation
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.
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 displays the Resolution Notice menu shown below.
Resolution Notice advises the optimal resolution to use.
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 “15 second” setting, if a control is not pushed within 15 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. Exception: This control does not affect changes made with the User Color control, Language Select or Power Lock setting.
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SHORT CUTS FUNCTION FROM THE BUTTONS
[1]
Main Menu
[2]
[▼] or [▲]
[▼] + [▲]
[1] + [2]
[1] + [▼] + [▲]
(keep pushing 5 sec)
[1] + [▼]
[1] + [▲]
Auto Image Adjust
To immediately activate Contrast menu. It should be change to Brightness OSD by push button [2]
recall both of Contrast and Brightness to default
toggle 720x400 and 640x400 mode when input 720x400 or 640x400 mode
White Balance (Not shown on user’s guide)
Power Lock
OSD Lock
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
Power Board
(Include: adapter, inverter)
AC-IN
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.
R G B H
V SDA SCL
CCFL Drive.
Key Board
EPROM EPROM
Flat Panel and CCFL backlight
Main Board
HOST Computer
PWPC board
TSUM16AK
OSC
RS232 Connector For white balance adjustment in factory mode
Video signal, DDC
Backlight and Panel
Keyboard
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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.
AC input
EMI filter
Lamp
OSC and Output Circuit
Feedback Circuit
Bridge Rectifier and Filter
Start Circuit R903, R904,R905
PWM
Control IC
DC Convert Circuit
Over Voltage
Transformer
MOSFET Q203
PWM Control IC
Rectifier CMOS
Over Vol tage Protect
CN902
5V
12V
ON/OF
ON/OFF Control
DIM
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4.4 INTRODUCTION OF IC
TSUM16AK(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
66 DDCA_SDA/RS232_RX DDC data for analog interface/UART
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
21 PWM1 PWM1; 4mA driving strength; Output 29 PWM0 PWM0; 4mA driving strength; Output
4 BYPASS For External Bypass Capacitor 32 XIN Xin; Crystal Oscillator Input 33 XOUT Xout; Crystal Oscillator Output
44、50、60 AVDD＿ADC
52 34
14、67、95、
103、115
12、68、97、
117
AIC1084-33PM (U702): DC power convert, used to 5v convert 3.3v. LT1117-18(U701): DC power convert, used to 5v convert 3.3v. PM25LV010-25SCE (U402): The PM25LV010 are 512 Kbit/1 Mbits 3.0 Volt-only serial
Flash memories. These devices are designed to use a single low voltage, ranging from 2.7 Volt to 3.6 Volt for 25MHz or from 3.0 Volt to 3.6 Volt for 33MHz to perform read, erase and program operations. The devices can be programmed in standard EPROM programmers as well.
AVDD＿PLL
AVDD＿MPLL
strength/UART transmitter/GPIO; I/O w/5V-tolrant
transmitter/GPIO; Input w/5V-tolrant
External resistor 390 ohm to AVDD＿ADC
ADC Power 3.3V PLL Power 3.3V MPLL Power 3.3V
VDDP Digital Output Power 3.3V
VDDC Digital Core Power 1.8V
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PIN Descriptions:
Symbol Type Description
CE# INPUT Chip Enable: CE# goes low activates the device’s internal
circuitries for device operation. CE# goes high deselects the device and switches into standby mode to reduce the power consumption. When the device is not selected, data will not be accepted via the serial input pin (SI), and the serial output pin (SO) will remain in a high impedance state.
SCK INPUT Serial Data Clock
SI INPUT Serial Data Input
SO OUTPUT Serial Data Output
GND Ground
Vcc Device Power Supply
WP# INPUT
HOLD# INPUT
Write Protect: When the WP# pin brought to low and WPEN bit is “1”, all write operations to the status register are inhibited. Hold: Pause serial communication with the master device without resetting the serial sequence.
Circuit Diagram
5
1
TDA7496L(U201): The TDA7496L is a stereo 2W+2W class AB power amplifier, specially
designed for high quality sound, TV and Monitor applications. Features of the UTC TDA7496L include linear volume control, Stand-by and mute functions. The function of each pin and the inside circuit diagram are as follows:
Block Diagram
PIN Function
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1
LD7575 PS (IC901): The LD7575 is a current-mode PWM controller with excellent
power-saving operation. The embedded over voltage protection, over load protection and the special green-mode control provide the solution for users to design a high performance power circuit easily and etc. The function of each pin and the inside circuit diagram are as follows:
PIN Descriptions:
Pin Name Function
1 RT 2 COMP
This pin is to program the switching frequency. By connection a resistor to ground to set the switching frequency.
Voltage feedback pin(same as the COMP pin in UC384X), By connecting a
photo-coupler to close the control loop and achieve the regulation. 3 CS Current sense pin, connect to sense the MOSFET current 4 GND Ground 5 OUT Gate drive output to drive the external MOSFET 6 VCC Supply voltage pin 7 NC Unconnected Pin
Connect this pin to positive of bulk capacitor to provide the startup current for the 8 HV
controller, when Vcc voltage trips the UVLO(on), this HV loop will be off to save
the power loss on the startup circuit.
Block Diagram
7
1
OZ9938GN(IC801): The OZ9938 is high performance, cost-effective CCFL controller designed
for driving large-size LCD applications requiring 2 to 6 CCFLs.PWM control, 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 Descriptions:
Pin Names Description
1 DRV1 Drive output 2 VDDA Supply voltage input 3 TIMER Timing capacitor to set striking time and shutdown delay time
4 DIM
Analog dimming or Internal LPWM dimming or external PWM pulse input for dimming function
5 ISEN Current sense feedback 6 VSEN Voltage sense feedback 7 OVPT Over-voltage/ over-current protection threshold setting pin 8 NC No connection 9 NC No connection
10 ENA ON/OFF control of IC 11 LCT
Timing capacitor to set internal PWM dimming frequency and also a pin for analog dimming selection
12 SSECMP Capacitor for soft start time and loop compensation 13 CT Timing resistor and capacitor for operation and striking frequency 14 GNDA Ground for analog signals 15 DRV2 Drive output 16 PGND Ground for power paths
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Block Diagram
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