ViewSonic VLCDS27955-1W, VLCDS27955-2W Service 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 - (800) 888-8583

(VG510b/s_SM_722 Rev. 1a Apr. 2004)

2004 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

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

1 2 5 7

14 22 24 25 33

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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

Red Video Signal

Green Video Signal

Blue Video Signal

N.C.

Ground

+5V

Ground

N.C.

DDC data

Horizontal sync signal

Vertical sync signal

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 plug the 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 limit for the output switch and an over temperature shutdown for complete protection under fault condition.

B. A/D converter

The MRT V3 is a highly integrated TFT LCD controller chip with the 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 supports both 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 is an 8051 CPU core embedded device specially tailored to LCD 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-byte internal program Flash-ROM .

4. Circuit Description

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First, power off the monitor, un-plug the AC cord and be sure the signal cable is

connected(D-sub connected) , then press “2” key at the same time and plug the AC cord to factory.

5. Adjusting Procedure

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START

Use Analog Native mode (Window Pattern )

Picture

visible?

Yes

Backlight

on?

On Off

Power LED

Green LED &

key pad work?

Yes

(1)Panel no power (2)Panel cable not connected (3)H/V sync process to panel

(1)Check Scaler H/V sync correct? (2)Measure at Scaler side

Check Inverter

Green

Check H/V sync

at 7414 output

Orange

Check Scaler

(1)Scaler no power (2)Scaler changed no OSC

Abnormal

Check input source Check 7414

Green + Orange

Check DC power 12V,5V,3.3V,2.5V ,MCU 3.3V

Check MCU crystal

Check MCU or Reprogram MCU

6. Trouble Shooting Flow Chart

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+ 26 hidden pages

ViewSonic VLCDS27955-1W, VLCDS27955-2W Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual