ViewSonic VA503b-2, VA503m-2, VS11357 Service manual

Service Manual

ViewSonic VA503b-2

VA503m-2

Model No. VS11357

15” Color TFT LCD Display

(VA503b-2_VA503m-2_SM Rev. 1a Aug. 2006)

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

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 8/21/2006 Initial Release Jamie. Chang

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TABLE OF CONTENTS

1. Precautions and Safety Notices 1

2. Specification 4

3. Front Panel Function Control Description 9

4. Circuit Description 15

5. Adjustment Procedure 24

6. Troubleshooting Flow Chart 38

7. Recommended Spare Parts List 46

8. Exploded Diagram and Exploded Parts List 49

9. Block Diagram 54

10. Schematic Diagrams 55

11. PCB Layout Diagrams 62

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1. Precautions and Safety Notices

1. SAFETY PRECAUTIONS

This monitor is manufactured and tested on a ground principle that a user’s safety comes first. However, improper
used or installation may cause damage to the monitor as well as to the user.

WARNINGS:

z This monitor should be operated only at the correct power sources indicated on the label on the rear of the monitor. If

you’re unsure of the power supply in you residence, consult your local dealer or Power Company.

z Use only the special power adapter that comes with this monitor for power input.
z Do not try to repair the monitor by yourself, as it contains no user-serviceable parts. Only the qualified technician can

repair it.

z Do not remove the monitor cabinet. There are high-voltage parts inside that may cause electric shock to human

bodies.

z Stop using the monitor if the cabinet is damaged. Have it checked by a service technician.
z Put your monitor only in a lean, cool, dry environment. If it gets wet, unplug the power cable immediately and consult

your closed dealer.

z 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.

z Do not place heavy objects on the monitor or power cord.

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 voltage, 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.

3. SERVICE NOTES

z When replacing parts or circuit boards, clamp the lead wires around terminals before soldering.

z Keep wires away from high voltage, high temperature components and sharp edges.

z Keep wires in their original position so as to reduce interference.

z Adjustment of this product please refers to the user’ manual.

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4. Handling and Placing Methods

Correct Methods: Incorrect Methods:

Only touch the metal of the LCD panel or the front
cover of he 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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Correct Methods: Incorrect Methods:

Place the monitor on a clean and soft foam pad.

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

1. INTPRODUCTION

FEATURES
Size 15 “
Luminance (Typ)
Contrast Ratio (Typ) 600:1

TFTLCD PANEL

Input Signal

Sync Compatibility

Compatibility

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

Power Consumption

Audio Yes(For VA503m Only)

Ergonomics

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

Dimension

Weight

Operating Condition

Storage Condition

Regulation

Colors (6 bits + 2 bits FRC) 16.2 M
Response Time (Typ) 8 ms
Viewing Angle (H/V) 150 ° / 130 °

Recommend resolution 1024 x 768 @60Hz

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

Digital No

Separate Sync Yes
Composite Sync No
Sync on Green No
PC Yes
Power Mac Yes

TV Box (NextVision 6) Yes

On Mode(Max)

Off Mode (Max)

Tilt ( 20 ° - -4 °) Yes
Swivel No
Pivot No
Height Adjust No

Physical (W x H x D) 378 x 400 x 210 mm
Package (W x H x D) 440 x 485 x 147 mm
Physical (Net Weight) 4.0 kg
Package (Gross Weight) 5.1 kg
Temperature ( / )℉℃ 32℉-104 / 0℉℃-40℃
Humidity (%) 20 % - 90 %
Temperature ( / )℉℃ -4℉-140 / ℉ -20℃-60℃
Humidity (%) 5 % - 90 %
UL/cUL, FCC DOC, CB, CE, NOM, MIC, IRAM/S, GS(Nemko), ERGO,
ISO13406-2 PAR Part 2, TCO’03, GOST, SASO, BSMI, CCC, (PSB),C-TICK,
EPA(Ver.4.0), Energy Star

VA503b-2 / VA503m-2

250 cd/㎡

≦ 23 W

≦ 1 W

2 GENERAL specification

Test Resolution & Frequency 1024 x 768 @ 60Hz

Test Image Size Full Size

Contrast and Brightness Controls

Factory Default:
Contrast = 70%, Brightness = 100%

3 VIDEO INTERFACE

Analog Input Connector DB-15 (Analog), refer the appendix A

Video Cable Strain Relief

Video Cable Connector DB-15 Pin out Compliant DDC 1/2B

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Equal to twice the weight of the monitor for five
minutes

Video Signals Video RGB (Analog) - Separate
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
DDC 1/2B Compliant with Revision 1.3
Sync Compatibility Separate Sync

Video Compatibility

Resolution Compatibility

Exclusions Not compatible with interlaced video

Shall be compatible with all PC type 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

4 POWER SUPPLY

Internal Power Supply

Part Number: ILPI-019
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 5 A typical at 14 VDC
Leakage Current 3.5 mA (Max) at 254VAC / 60Hz
Efficiency 80 % typical at 115VAC Full Load

Fuse Internal and not user replaceable
Power Dissipation 23 Watts (max)
Max Input AC Current 1.2 Arms @ 100VAC, 0.6 Arms @240VAC
Inrush Current (Cold Start) 40A @ 120 VAC, 60 A(max) @ 220 VAC

Shall start and function properly when

Power Supply Cold Start

under full load, with all combinations of

input 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
Power Supply Line Surge Immunity

nominal line voltage for one cycle with no

damage

Shall be able to function properly, without

Power Supply Missing Cycle Immunity

reset or visible screen artifacts, when ½

cycle of AC power is randomly missing at

nominal input

The power supply shall not produce audible

noise that would be detectable by the user.

Power Supply Acoustics

Audible shall define 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

Length = 1.8m. Connects to AC/DC Power

Color = Black
Power Saving Operation(Method) VESA DPMS Signaling

Power Consumption

ON Mode < 23 W (max)

POWER SAVING < 2W ,OFF < 1W
Recovery Time On Mode = N/A, Active Off < 3 sec

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5 ELECTRICAL REQUIREMENT

Horizontal / Vertical Frequency

Horizontal Frequency 30 – 62 kHz

50 – 85* Hz.

Vertical Refresh Rate

Maximum Pixel Clock 80 MHz
Sync Polarity

Timing Table

Item Timing Analog

1 640 x 350 @ 70Hz, 31.5kHz
2 640 x 400 @ 70Hz
3 640 x 480 @ 50Hz
4 640 x 480 @ 60Hz, 31.5kHz
5 640 x 480 @ 67Hz, 35.0kHz
6 640 x 480 @ 72Hz, 37.9kHz
7 640 x 480 @ 75Hz, 37.5kHz
8 640 x 480 @ 85Hz, 43.27kHz

9 720 x 400 @ 70Hz, 31.5kHz
10 800 x 600 @ 56Hz, 35.1kHz
11 800 x 600 @ 60Hz, 37.9kHz
12 800 x 600 @ 72Hz, 48.1kHz
13 800 x 600 @ 75Hz, 46.9kHz
14 800 x 600 @ 85Hz, 53.7kHz
15 832 x 624 @ 75Hz, 49.7kHz
16 1024 x 768 @ 60Hz, 48.4kHz
17 1024 x 768 @ 70Hz, 56.5kHz
18 1024 x 768 @ 72Hz, 58.1kHz
19 1024 x 768 @ 75Hz, 60.0kHz

*1. Tolerance ≧ ± 2kHz.
*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 85Hz mode might be worse than 75Hz.

Primary Presets

1024 x 768 @ 60Hz

User Presets

Number of User Presets (recognized timings) Available: 10 presets total in FIFO configuration

Changing Modes

● Maximum Mode Change Blank Time for image stability: 3 seconds (Max), excluding “Auto Image Adjust” time.

● Under DOS mode (640 x 350, 720 x 400 & 640 x 400), it should recall factory setting when execute “Auto Image

Adjust”.

The monitor needs to do “Auto Image Adjust” the first time when a new mode is detected. (See section “0-Touch™

* When the resolution is set to 1024 x 768 , the vertical refresh
rate may be up to 75 Hz; for other resolutions, the vertical refresh
rate may be up to 85Hz.

Independent of sync polarity.

Yes
Yes
Yes
Yes
Yes
Yes
Yes

*3

Yes

Yes
Yes
Yes
Yes
Yes

*3

Yes

Yes
Yes
Yes
Yes
Yes

Function Actions”)

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Main Menu Controls
Auto Image Adjust

Contrast/Brightness*
Audio Adjust (For VA503m only)

1

Volume*3, Mute*3

Color Adjust

sRGB, 9300K, 6500K(default), 5400, User Color [R, G, B]
Information
H Frequency, V Frequency, Pixel Clock, Resolution, Serial Number, Model Number,

“www.ViewSonic.com

Manual Image Adjust

H. Size, H/V Position

”

,

Fine Tune, Sharpness*2

Setup Menu

Language [English, French, German, Italian, Spanish, Finnish, Simplified Chinese

1

Traditional Chinese, Japanese], Resolution Notice, OSD Position*

4

Timeout*

Memory Recall

1

These functions can be recalled to default by [▼]+ [▲]

*

2

These functions are not available under Native Resolution Mode

*

3

These functions setting can be recalled to default by [▼]+[▲] under audio mode

*

4

The function execute are 5,15,30,60sec

*

, OSD Background

, OSD

[Remark] Please refer to the detail in the Appendix C

Factory Defaults

Item Defaults Item Defaults

Contrast 70% Volume

(For VA503m only)

50%

Brightness 100% Balance N/A
Color Temperature 6500K Treble N/A
Sharpness 0% Bass N/A
OSD H. Position 50% 720x400/640x400 720x400

OSD V. Position 50%

OSD Time Out 15 Sec

640x480@60Hz
720x480@60Hz

In SOG and Composite,

720x480@60Hz

640x480@60Hz

N/A

640x480@60Hz

In SOG and Composite,

OSD Background Enabled

1152x864@75Hz

N/A

1152x870@75Hz

In SOG and Composite,

Resolution Notice Enabled

1280x768@60/75/85Hz
1024x768@60/75/85Hz

N/A

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AUDIO INTERFACE (SPEAKER SPECIFICATION) --- (For VA503m only)

Line input connection 3.5 mm stereo jack
Line input signal 1.0Vrms
Line input impedance >10 kOhm
Maximum power output (Electric) 1 W @ < 8% distortion
Signal to Noise Ratio 50 dB
Frequency response 500 Hz – 20 Khz

Distortion

< 8 % THD (@1kHz)

There should be no audible vibration with

Vibration

volume at 100%. (Input signal within 1.0
Vrms)

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

Note: There is no guarantee <1 W power
Audio DPMS

consumption in Active Off mode, when the

Audio Cable is connected

TFT LCD PANEL

st

Panel Source

1

INN MT150XN03 V0
Type TN, LVDS
Active Size 304.1 mm (H) x 228.1mm (V)
Pixel Arrangement RGB Vertical Stripe
Pixel Pitch 0.297 mm
Glass Treatment Anti Glare (Hard coating 3H)
# of Backlights 2 CCFL edge-light
Backlight Life 30,000 Hours (Min) (@8mA)
Luminance –Condition: CT = 6500 K

Contrast = Max, Brightness = Max

250 cd/m2 (Typ after 30 minute warm up)

200 cd/m2 (Min after 30 minute warm up)

Brightness Uniformity 80% (typ) / 75 % (min)
Contrast Ratio 700 :1 (Typ), 500 :1 (Min)
Color Depth Vertical) 16.2 million colors (6+2 bit panel)
Viewing Angle (Horizontal) 150 deg (Typ)@ CR>10
Viewing Angle (Vertical) 130 deg (Typ) @ CR>10
Response Time
10%-90% @ Ta=25°C

8 ms (Tr= 2 ms, Tf = 6 ms) (Typ)

16 ms (Tr= 4 ms, Tf = 12 ms) (max)

Panel Defects Please see Panel Quality Specifications.

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3. Front Panel Function Control Description

Adjusting the Screen Image

Use the buttons on the front control panel to display and adjust the OSD controls which display
on the screen. The OSD controls are explained at the top of the next page and are defined in
“Main Menu Controls” on page 10.

Main Menu

with OSD controls

Displays the control screen

for the highlighted control.

Also toggles between two

controls on some screens.

Also a shortcut to Auto

Image Adjust.

Displays the

Main Menu or

exits the

control screen

and saves

adjustments.

Front Control Panel

shown below in detail

Power light
Green = ON
Orange = Power Saving

Standby Power
On/Off

Scrolls through
menu options and
adjusts the
displayed control.

Also a shortcut to
display the
Contrast
adjustment control
screen.

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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, pressSorTto 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 S 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. (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 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.

Audio Adjust
Vol ume 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).

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 1024 x 768 @ 60Hz (recommended) means that the resolution is
1024 x 768 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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4. Circuit Description

2. Electronic Circuit Theory

2.1 Switching Mode Power Supply

2.1.1 AC Current Input Circuit

P801 is a connector for connecting AC Power. F801 is a fuse to protect all the circuit. AC input voltage is from
90V to 264V. R820 and R821 joined between two inputting main circuit to prevent man from shock. L801 is used to
clear up low frequency wave. C801 and C806 are used to discharge the waves that L801 produced. High
frequency waves are damped by C801 and C806. D801 is a rectifier which composed of 4 build-in diodes, it inverts
AC to DC.

2.1.2 High Voltage to Low Voltage Control Circuit

C805 is used to smooth the wave from rectifier. IC802 is a highly integrated PWM controller, which build-in a
power MOSFET. When rectified DC high voltage is applied to the DRAIN pin during start-up, the MOSFET is off
initially, and the CONTROL pin capacitor is charged through a switched high voltage current source connected
internally between the DRAIN and CONTROL pins. When the CONTROL pin voltage Vc reaches approximately

5.8V, the control circuitry is activated and the soft-start begins. The soft-start circuit gradually increases the duty
cycle of the MOSFET from zero to the maximum value over approximately 10ms. If no external feedback/supply
current is fed into the CONTROL pin by the end of the soft-start, the high voltage current source is turned off and
the CONTROL pin will start discharging in response to the supply current drawn by the control circuitry.

Resistor R803, R807, R824 and R825 are for line over voltage shut-down (OVP) and line under-voltage
detection (UVP).Resistors R801, R805, R822, and R823 are for external current limit adjustment, and used to
reduce the current limit externally to a value close to the operating peak current of primary about 1.35A. The mean
is power will protected when the primary current over about 1.35A.

When PWM is turned off, the main current flow will be consumed through D804 and ZD802, This will prevent
MOSFET which built-in IC802 from being damaged under large current impulse and voltage spike.

D806 and C815 provide internal Auxiliary current to CONTROL pin during normal operation. In addition, error
amplifier and feedback current to the CONTROL pin are for duty cycle control.

2.1.3 DC_5V and DC_14V Output Circuit

For DC 5V, D805 is used to rectify the inducted current. R806 and C811 are used to store energy when current
is reversed. The parts including C812, C814, C822, C821, B801 and L803 are used to smooth the current waves.

For DC 14V, D803 is used to rectify the inducted current. R802 and C802 are used to store energy when
current is reversed. The parts including C808, C810 and L802 are used to smooth the current waves.

2.1.4 Feedback and OVP Protect Circuit

Pin R of IC803 is supplied 2.5V stable voltage. It is connected to 5V and 14V output through R811,
R810 and R818. R811, R810 and R818 are output sampling resistor. When the sampling voltage more
than 2.5V or less than 2.5V, feedback current of IC802 will change, this can change the voltage from
transformer T801.

Q802, R827, R828 and ZD801 make up of dummy loading circuit. For start-up sequence, during 5V
output take place high loading first, this dummy loading circuit operated to insure 14V not be increased.

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2. 2 Inverter Circuit

2.2.1 Low voltage to high voltage circuit

14VDC provides the power for IC501; the control signals Brightness and ON/OFF come from I/F board.

ON/OFF signal connect to pin10 of IC501 and makes IC501 enable. Brightness signal connect to pin4 of IC501
and regulates the panel brightness, R526, R529, C505 make up a network of delaying time circuit and R523, R524
make up a divided voltage network, C504 is used to dump noise. The operation frequency is determined by the
external Resistor R522 and capacitor C529 connected to pin13 of IC501. BURST MODE regulated dimming
frequency is determined by the external resistor R527 and capacitor C506 connected to pin11 of IC501. C508 is
used for soft start and compensation, C507, C505 are used for dump noise.

The output drives, include DRV1, DRV2 (pins1,15 respectively) output square pulses to drive MOSFET U501,
U502, and each of U501, U502 , is consist of a N channel MOSFET. U501,OR U502 work as Push-Pull- topology, it
is high efficient, PWM switching.

During start up, VSEN (pin6) senses the voltage at the transformer secondary. When VSEN reaches 3.0V, the

output voltage is regulated. If no current is sensed approximately 2seconds IC501 shut off.

The current flowing through CCFL is sensed and regulated through sense resistor R509, R534. The feedback
voltage connected to Pin5 (ISEN), then compared with a reference voltage (1.5V) via a current amplifier, resulting in
PWM drive outputs to PUSH-PULL switches.

2.2.2 Protection circuit

Over Voltage Protection and over-current protection are monitored by the voltage on VSEN(Pin 6) During
normal operation , if a CCFL is damaged or removed ,the voltage at VSEN (Pin6) increases .Once the voltage at
VSEN exceeds 2.0V (OVPT Setting) the driver output duty cycle is regulated and the shutdown delay timer is
activated.OVPT set the overall protection threshold voltage that is lower than 3V (VSEN threshold). Once the
voltage at TIMER pin reached about 3v ,the IC will shut down and latch .R501, R503,C525,C527 are connected in
high voltage output connector, the divided AC voltage is inverted DC voltage through D503,
D504,D507,D508 ,R530 and C516are used to rectify wave & dump noise. Then the voltage signal reaches Pin6
VSEN of IC501, when the voltage changes, build-in PWM of IC501 will adjust output voltage.

Open Lamp Protection: In normal operation, R509 are sensed a high level DC voltage,If a CCFL is removed
or damaged during normal ,the voltage at SSTCMP(Pin12) rises rapidly .when the voltage at SSTCMP reaches a
threshold of approximately 2.5V,a current source charges the capacitor(C511)connected to TIMER(Pin3).Once the
voltage level at the TIMER pin reaches a threshold of approximately 3v,The drive outputs shut down and latch.

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2.3 I/F Board Circuit

2.3.1 Power Input

+3.3V is from the power board and supply for U101(LD1117AL-1.8V)﹑U102(AT24C02N) ﹑U103(TSUM16AL) ﹑
U104(SST25VF010A) ﹑U105(AT24C04N) ﹑panel and LED. +1.8V output is generated from +3.3V through C104
and C105 filtering, and U101 outputs. +1.8V is only used for U105.

2.3.2 MCU & Scaler(TSUM16AL)

The frequency of XTAL1 is 14.318MHz. U103 # 48 is defined as panel-enable. When the I/O port is low, Q106 and
Q105 are conducted. And then after C116 and C117 filtering, obtain the voltage of VLCD, which will be connected
to CN104. U103 # 85 is defined as CCFL-enable. When the I/O port is low, Q102 is pulled up and the backlights
are on; When the I/O port is high, Q106 is conducted and the backlights are off. U103 # 35 is defined as DET-VGA,
connected with CN103 # 5. U103 # 84 is a pin of hardwire reset. U103 # 54-# 55,# 58-# 65 output LVDS digital
data of 8 bit to panel control circuit through CN104. U103 # 86 generates a PWM waveform by regulating the duty
to control the brightness of the backlights.
U102 is EEPROM used for saving EDID data, which is connected by SCL and SDA pins with # 31 and # 30 of
TSUM16AL.
U104 is a flash memory, U104 # 2, # 1, # 6, # 5 are the communications with U103 # 37-# 40.
U105 is EEPROM used for saving user’s OSD setting. U105 is connected by SCL and SDA pin with # 44 and # 43
of TSUM16AL.

2.3.3 VGA Input

Signal R, G, B input through CN103 # 1, # 2, # 3, and C116, C117 and C118 filtering the high frequency noise.
Signal HSYNC and VSYNC input through CN103 #13 and #14, and C126, R131, C125, R130 filtering. Then the
analog signal enters U103, and then U103 deals with it internally. In addition, D101, D102, D103, D104 (the four
are BAV99), ZD101, ZD102, ZD103, ZD104, ZD105 (they are constant voltage diode of 5V6) are ESD protector.
Signal DDC-SCL inputs via CN103 # 15, and then passes through ZD101 for ESD protection, goes into EDID
EEPROM IC U102. Signal DDC-SDA inputs via CN103 #12, and then passes through ZD105 for ESD protection,
goes into EDID EEPROM IC U102. CN103 # 5 is defined as cable detect pin, this detector realizes via R126 and
U103 # 35,The PC-5V of U102 is supplied by PC via CN103 # 9 with ZD102 for ESD protection, or supplied by
Monitor self via D105.U105 is an EEPROM IC, which is a kind of memory and used for saving EDID data.

2.3.4 Button Control

Button “Key-Power” is defined as power on/off, which is connected to U103 # 90 through CN101 # 6.
Button “Key-2” is defined as two functions of selecting and adjustment, which is connected to U103 # 94 through
CN101 # 5.
Button “Key-Up” is defined as plus, which is connected to U103 # 95 through CN101 # 8.
Button “Key-Down” is defined as minus, which is connected to U103 # 99 through CN101 # 7.
Button “Key-1” is defined as two functions of menu and exit, which is connected to U105 # 89 through CN105 # 4.
LED indicator on the front bezel is defined as follows:
a. When press button “Key-Power”, U103 # 91 is pulled low and U103 # 92 is pulled high, so Q103 is conducted

and the LED indicator is green.

b. When in power-saving mode, U103 # 91 is pulled high and U103 # 92 is pulled low, so Q104 is conducted and

the LED indicator is orange.

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3. FACTORY PRESET TIMING TABLE

TIMING

640x350@70Hz

640x400@70Hz

720x400@70Hz

640x480@50Hz

640x480@60Hz

640x480@67Hz

FH(KHz)
FV(Hz)

31.469 + 800 640 96 48

70.086 − 449 350 2 60

31.469 − 800 640 96 48 IBM

70.086 − 449 400 2 35

31.469 − 900 720 108 54 IBM

70.087 + 449 400 2 35

24.700 − 800 640 96 48

50.000 − 494 480 2 8

31.469 − 800 640 96 40 VESA

59.940 − 525 480 2 25

35.000 ( 864 640 64 96

66.667 ( 525 480 3 39

Sync
Polarity

Total
(Dot/Line)

37.861 ( 832 640 40 120 VESA

640x480@72Hz

72.809 ( 520 480 3 20

37.500 ( 840 640 64 120 VESA

640x480@75Hz
VESA

640*480@85Hz

800x600@56Hz

800x600@60Hz

800x600@72Hz

800x600@75Hz

VESA
800*600@85Hz

832x624@75Hz

1024x768@60Hz

1024*768@70Hz

1024*768@75Hz

1024*768@72Hz

75.000 ( 500 480 3 16

43.269 ( 832

85.008

35.156 + 1024 800 72 128 VESA

56.250 + 625 600 2 22

37.879 + 1056 800 128 88 VESA

60.317 + 628 600 4 23

48.077 + 1040 800 120 64 VESA

72.188 + 666 600 6 23

46.875 + 1056 800 80 160 VESA

75.000 + 625 600 3 21

−

53.674 + 1048 800 64 152

85.061 + 631 600 3 27

49.726 − 1152 832 64 224 MAC

74.550 − 667 632 3 39

48.363 − 1344 1024 136 160 VESA

60.004 − 806 768 6 29

56.476 − 1328 1024 136 144 VESA

70.069 − 806 768 6 29

60.023 + 1312 1024 96 176 VESA

75.029 + 800 768 3 28

57.700 − 1360 1024 136 144

72.125 − 800 768 6 26

509 480 3 25

Active
(Dot/Line)

Sync Width
(Dot/Line)

Back Porch
(Dot/Line)

640 56 80

Pixel
Freq.(MHz)

25.175

25.175

28.322

19.760

25.175

30.240

31.500

31.500

36.000

36.000

40.000

50.000

49.500

56.250

57.283

65.000

75.000

78.750

78.472

4. Power On/Off Sequence

4.1 Hardware Power ON

When power cord is plugged into AC socket, SMPS starts work and provides U103 with VCC3.3V. When VCC3.3V
inputs, U103 resets circuit active, sets U103 all registers to preset modes, and then monitor goes into stand-by
mode. That means hardware power on has been completed.

4.2 Software Power ON/OFF

When press power key, U103 # 90 recieves low pulse,and then U103 will do the power on/off.

- If Power ON, U105 # 91(LED_Green) will send out Low potential, and then LED green on.

- If Power OFF, U105 # 91(LED_Green) will send out High potential, and then LED Off.

The Panel_Vcc, Backlight_En, CLK/DATA output to panel will follow the following sequency.

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T1 (ms) T2 (ms) T3 (ms) T4 (ms) T5 (ms) T6 (ms) T7 (ms)

0.5~10 0~50 > 200 > 200 0~50

5. AC Outlet Pin Assignment

3

1 2

Pin Symbol Description

1 L Live

2 N Neutral

﹤100

> 500

P801

3 E GND

6. Inner Connector Pin Assignment

6.1 CN501, CN502, CN503, CN504 (Connect to Panel Backlight, SM02B-BHSS-1-TB or equivalent)

Pin Symbol Description

1 H.V. High voltage for lamp
2 L.V. Low voltage for lamp

6.2 CN101 (Power BD to Interface BD)

Pin No. Symbol Description

1 VCC3.3 +3.4V INPUT

2 VCC3.3 +3.4V INPUT

3 GND GND

4 ON/OFF CCFL on/off control

5 BRIGHTNESS Panel luminance control (CCFL brightness)

6 GND Ground

7 VOL Volume control input (For VA503m only)

8 MUTE Mute control input (For VA503m only)

6.3 CN106 (Interface BD to Keypad)

Pin

No.

1 LED_ORANGE Orange LED lighting control

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Symbol Description

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