ViewSonic VLCDS27955-1W User manual

Model No. VLCDS27955-1W/-2W
15” Color TFT LCD Display
Service Manual
ViewSonic VG510b/s-1
ViewSonic
381 Brea Canyon Road, Walnut, California 91789 USA - [phone]
(VG510b/s_SM_722 Rev. 1aApr. 2004)

Copyright
Copyright
¤
2004by ViewSonic Corporation. All rights reserved. No partof 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
ViewSonic is a registered trademark of ViewSonic Corporation.
All other trademarks used within this document are the property of their respective owners.
Optiquest is a registered trademark of ViewSonic Corporation.
Revision History
Revision Date Description Of Changes Approval
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1a 04/14/04 Initial Release DCN-3611 Angela Lu

TABLE OF CONTENTS
2. Specification
3. Front Panel Function Control Description
4. Circuit Description
6. Trouble Shooting Flow Chart
9. Block Diagram
10. Schematic Diagrams
7. Recommended Spare Parts List
1. Precautions and Safety Notices
5. Adjusting Procedure
8. Exploded Diagram And Spare Parts List
11. PCB Layout Diagrams
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Prior to using this manual, please ensure that you have carefully followed all the procedures
outlined in the user manual for this product.
Read all of these instructions.
Save these instructions for later use.
Follow all warnings and instructions marked on the product.
Do not use this product near water.
This display should be installed on a solid horizontal base.
When cleaning, use only a neutral detergent cleaner with a soft damp cloth. Do not spray with
liquid or aerosol cleaners.
Do not expose this display to direct sunlight or heat. Hot air may cause damage to the cabinet
and other parts.
Adequate ventilation must be maintained to ensure reliable and continued operation and to
protect the display from overheating. Do not block ventilation slots and openings with
objects or install the display in a place where ventilation may be hindered.
Do not install this display near a motor or transformer where strong magnetism is generated.
Images on the display will become distorted and the color irregular.
Do not allow metal pieces or objects of any kind fall into the display from ventilation holes.
Slots and openings in the cabinet and the back or bottom are provided for ventilation, to ensure
reliable operation of the product and to protect it from overheating, those openings muse not
be blocked or covered. The openings should never be blocked by placing the product on a bed,
sofa, rug, or other similar surface. This product should never be placed near or over a radiator
or heat register. This product should not be placed in a built-in installation unless proper ventilation
1. Precautions and Safety Notices
is provided.
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2.1. PRODUCT SPECIFICATIONS
LCD panel type 15.0” TFT (15.0” Diagonal)
Displayable resolution XGA 1024 x 768 maximum
Pixel dimension 0.297 mm horizontal x 0.297 mm vertical
LCD display color 16.8M Colors Max.
OSD control AUTO CONFIG, BRIGHTNSS,
CONTRAST, COLOR (R, G, B, BLACK LEVEL ADJUST),
POSITION(H-POSITION, V-POSITION ),IMAGE (PHASE,
CLOCK ),
SETUP MENU (RESET,OSD POSITION, SYSTEM INFO )
Manualcontrolbuttons MENU, Select, Adjust(up,down), Power.Mute,+,-
Viewing angle Horizontal: ±60 , Vertical: -45~+55.
Tilt +20°, -5°.
Contrast ratio 350:1 (typ) , 250:1 (min)
Brightness 250 cd/m2 (typ), 200 cd/m2 (min)
Response time 25ms (typ) tr+tf , 60ms (max) tr+tf
Active display area 304.1 mm (H) x228.1mm (V)
AC/DC adapter Input: AC 100 ~ 240V, 50 ~ 60 Hz
Output: +12 V DC.
Input signal Video: Analog 0.7 Vp-p. 75 ohms
Sync. : TTL Level, Positive/ Negative, Separate Sync.
Input connector 15 Pin D-Sub.
Power management yes
Dimensions ( WxHxD ) 34.6 cm x 35.5 cm x 15.6 cm.
Weight 2.7 kgs. (LCD Module only)
3.4kgs. (unit)
Accessory VGA cable, AC/DC adapter, power cord.
Temperature Operation : 0 ~ 50°C
Storage : -20 ~ 60°C
Color temp (white) White x 0.313±0.03 , white y 0.329±0.03
2. Specification
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2.2. FACTORY SUPPORTING MODES
Prim
Factory Preset Modes
ary Preset VESA 1024 x 768 @ 60 Hz
1. 640 x 350 @ 70Hz, 31.5kHz
2. 640 x 480 @ 60Hz, 31.5kHz
3. 640 x 480 @ 67Hz, 35.0kHz
4. 640 x 480 @ 75Hz, 37.5kHz
5. 640 x 480 @ 72Hz, 37.9kHz
6. 720 x 400 @ 70Hz, 31.5kHz
7. 800 x 600 @ 56Hz, 35.1kHz
8. 800 x 600 @ 60Hz, 37.9kHz
9. 800 x 600 @ 75Hz, 46.9kHz
10. 800 x 600 @ 72Hz, 48.1kHz
11. 800 x 600 @ 85Hz, 53.7kHz
12. 832 x 624 @ 75Hz, 49.7kHz
13. 1024 x 768 @ 60Hz, 48.4kHz
14. 1024 x 768 @ 70Hz, 56.5kHz
15. 1024 x 768 @ 72Hz, 58.1kHz
16.1024 x 768 @ 75Hz, 60.0kHz
2.3. D-SUB CONNECTOR
This section describes the pin assignment of the LCD’s video connector. It is called 15 Pin
Pin NO. Signal Connector
1 Red Video Signal
2 Green Video Signal
3 Blue Video Signal
4 N.C.
5 Ground
6 Ground
7 Ground
8 Ground
9 +5V
10 Ground
11 N.C.
12 DDC data
13 Horizontal sync signal
14 Vertical sync signal
15 DDC clock
Mini D-sub Connector.
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Table 3.1: 15 pin D-sub connector pin assignment
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 Ground
11 No connection
12 (SDA)
13 Horizontal sync (Composite sync)
14 Vertical sync
15 (SCL)
Table 3.2: 24 pin DVI-D connector pin assignment
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 Control Description

2) SELECT:
To confirm the current selection. It also used for go back to previous menu for sub-menu,
and the change data will be save to memory.
3)ADJUST :
To scroll up in sub menu or to increase value of selected item.
4) ADJUST▲:
To scroll down in sub menu or to decrease value of selected item.
5) POWER SWITCH
Pushing the power switch will turn the monitor on. Pushing it again to turn the monitor off.
6) POWER INDICATOR
The LED will light with green color in normal on state, and will light with orange
color in power saving mode.
7) BRIGHTNESS/CONTRAST:
Press button UP/DOWN
8)AUTOIMAGEADIUST:
press button [2]
9) OSD LOCK AND UNLOCK:
press two buttons [1] & [UP] simultaneously for 10 seconds
10)POWER LOCK AND UNLOCK:
press two buttons [1] & [DOWN] simultaneously for 10 seconds
11) ALL RESET:
First,power off the monitor, un-plug the AC cord, then press [2] key at the same time and
12) FACTORY MODE:
First,power off the monitor, un-plug the AC cord and be sure the signal cable is connected
(D-sub connected),then press[ ] key at the same time and plug the AC cord.
13) RUN-IN MODE:
First ,power off the monitor, up-plug the AC cord and be sure the cable is not connected
D-Sub not connected),then press [1] key at the same time and plugthe AC cord.
14) AUTO COLOR:
press three buttons [1] & [up] & [down], this function only use for 1024x768 60hz patten
42/of Chroma 2135 signal generator.
NOTE:
chroma Patten 42
1) MENU:
Enter to the OSD adjustment menu. It also used for go back to previous menu for sub-menu,
and the change data don’t save to memory.
plug the AC cord
▼
▲
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WORKING THEOREM
A. DC-DC CONVERTER
This brick converts the 12V input voltage to 5V for panel use and 3.3V for controller use.
It consists of a PWM IC (AP1501), flywheel Diode (D1), buck choke (L2), and capacitor (C70,71).
AP1501 is a PWM generator working at 150Khz.
Self protection features include a two stage frequency reducing current limitfor the output
switch and an over temperature shutdown for complete protection under fault condition.
B. A/D converter
The MRT V3 is a highlyintegrated TFT LCD controller chipwiththe latest MRT advanced imageprocessing
technology and an integrated ADC/PLL. The MV3 has advanced programmable non-linear parametric
cubic based scaling engine with proprietary sharpness adjustment and text enhancement. MV3 supportsboth
analog and digital interfaced inputs with an internal ADC/PLL.
The MV3 has robust handling of a wide variety of TFT LCD panels and strong support of standard
or non-standard input timings.
. Integrated high speed triple 8-bit ADC/PLL support up to 140MHz for XGA-75Hz
. Advanced image processing with proprietary non linear parametric cubic based scaling engineSupport dual
interface with an integrated ADC/PLL
. Robust auto configuration for input mode detection and
clock frequency and phase recovery for standard or nonstandard input timing
. Support video processing with on-chip 2D de-interlacing
and color space conversion
. Support programmable Gamma Correction
. GPIO pins for flexible system design
D. MCU:
The MTV312M64 micro-controller isan 8051 CPU core embedded device speciallytailored toLCD monitor
applications. It include an 8051 CPU core, 1024-byte SRAM, 14 built-in PWM DACs, VESA DDC interface,
4 channel 6bit A/D converter, a 64 K-byteinternal program Flash-ROM .
4. Circuit Description
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