ViewSonic VG150m-1, VG150mb-1, VLCDS23587-3W, VLCDS23587-4W Service Manual

ViewSonic VG150m-1

Model No.VLCDS23587-3W

Service Manual

15” Color TFT LCD Display

( VG150m-1_SM_547-R ev.1 a –Dec 2 0 02 )

ViewSonic

“ 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-858

3

VG150mb-1

VLCDS23587-4W

Copyright

Copyright © 2002 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.

Revision History

Revision Date Description Approval

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1a 12/17/02 Initial Release DCN-2256 C.Shen

TABLE OF CONTENTS

Chapter 1 Precautions and Notices…………………………………………1

Chapter 2 Specification…………………………………………………….....3

2-1 General Specification………………………………………....3

2-2 Factory Preset Timing…………………………………….......4

2-3 D-Sub Connector Pin Assignment…………………………...5

Chapter 3 Disassembly / Assembly Instructions………………………...6
Chapter 4 Electronic Circuit Description…………………………………..7

4-1 Block Diagram………………………………………………….7
4-2 Main Board I/O Connections………………………………….8
4-3 Inverter Board I/O Connections………………………………8
4-4 Theory of Circuit Operation……………………………………9

Chapter 5 Adjustment………………………………………………………….24
Chapter 6 Troubleshooting Flow Chart…………………………………..26

6-1 Figures of Wave Form……………………………………….26
6-2 Troubleshooting Flow Chart…………………...……………29

Chapter 7 Schematic Diagrams…………………………………………….33
Chapter 8 PCB Layout…………………………………………………………37
Chapter 9 Exploded Diagram and Mechanical Parts List…………………41
Chapter 10 Recommended Spare Parts List………………………………….43
Chapter 11 Complete Parts List……………………………………………...44

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Appendix

Reader's Response

1. Precautions and Notices

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 must 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 is
provided.

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FCC Statement

This equipment has been tested and found to comply with the limits of Class B digital device, pursuant to part
15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference
in a residential installation. This equipment generates and can radiate radio frequency energy, and if
not installed and used in accordance with the instructions, may cause harmful interference to radio
communication. However, there is no guarantee that the interference will not occur in a particular installation.
If this equipment does cause unacceptable interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the interference by
one or more of following measures

Κ



Reorient or relocate the receiving antenna.



Increase the separation between equipment and receiver.



Connect into an outlet on circuit different from that to which the receiver is connected.



Consult the dealer or an experience radio/TV technician for help.

FCC Warning

To assure continued FCC compliance the user must use a grounded power supply cord and the provided
shielded video interface cable with bonded ferrite cores. Also, unauthorized changes or modifications to
ViewSonic products will void the usercs authority to operate this device. Thus ViewSonic will not be held
responsible for the product and its safety.

CE Certification

This device complies with the requirements of the ECC directive 89/3366/EEC with regard to
sElectromagnetic compatibility.s

Safety Guidelines

Caution: Use a power cable properly grounded. Always use the AC Mains cords listed below for each area

Κ

USA

(UL)

Canada

(CSA)

Germany

(VDE)

Switzerland

(SEV)

Britain

(BASE/BS)

Japan

(Electric Appliance Control Act)

In other areas, use AC cord which meets the local safety standards.

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2. Specification

2-1 General Specification

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Characteristic Description

LCD Panel Mitsubishi 15.0” AA150XC01, 0.297mm (H/V), Anti-glare
Maximum Viewing Angles Horizontal: 150 degrees @ CRЊ10

Vertical: 110 degrees @ CRЊ10

Signal Input VideoΚRGB analog

SyncΚH.V. Separate Sync, H.V. Composite Sync

(TTL Compatible), Sync. On Green
HorizontalΚ30 to 62KHz
Vertical Κ50 to 75Hz

Connector Analog: 15 Pin Mini D-Sub
Maximum Resolution 1024x768
Video Bandwidth 85 MHz nominal
Display Area 304.1 mm (H) x 228.1 mm (V)
Power Voltage 87~264VAC @ 47~63 Hz
Power Consumption 40W max. (Adaptor plus monitor)
Operating Conditions Temperature : 32л to 104л (0к to 40к)

Humidity : 10% to 90% (no condensation)
Altitude : 0 to +3,000 meters

Storage Conditions Temperature : -4л to +140л (-20к to +60к)

Humidity : 10% to 90% (no condensation)
Altitude : 0 to +12,000 meters

Mechanical Dimensions Width: 359.0mm / 14.13”

Height: 325.0mm / 12.8”
Depth: 190.5mm / 7.5”
Depth side view panel w/o base: 49.0mm / 1.92”
Monitor Weight: 3.3Kg / 7.3 lbs

Package Dimensions Width: 480.0mm / 18.9“

Height: 425.0mm / 16.7”
Depth: 110.0mm / 4.3”
Gross: 5.1Kg (11.2 lbs)

2-2 Factory Preset Timing

This timing chart is already preset for the TFT LCD monitors.

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Timing Horizontal

Polarity

Horizontal

Frequency

Vertical
Polarity

Vertical

Frequency

VGA 640x350 + 31.47 kHz - 70.09 Hz
VGA 720x400 - 31.46 + 70.08
VGA 640x400 - 31.46 + 70.08

VGA 640x480 - 31.47 - 60.05
VESA 640x480 - 37.86 - 72.81
VESA 640x480 - 37.50 - 75.00

MAC 640x480 Composite 35.00 Ѻ 66.66
VESA 800x600 + 35.15 + 56.25
VESA 800x600 + 37.87 + 60.31
VESA 800x600 + 48.07 + 72.18
VESA 800x600 + 46.87 + 75.00

MAC 832x624 SOG 37.86 Ѻ 72.80

VESA 1024x768 - 48.36 - 60.00
VESA 1024x768 - 56.47 - 70.06
VESA 1024x768 - 58.03 - 71.91
VESA 1024x768 + 60.02 + 75.02

MAC 1024x768 Composite 60.24 Ѻ 74.92

2-3 D-Sub connector Pin Assignment

The TFT LCD analog display monitors use a 15 Pin Mini D-Sub connector
as video input source.

Pin Number Pin Description

1 Red video input
2 Green video input
3 Blue video input
4 Ground
5 Ground
6 R video ground
7 G video ground
8 B video ground

9 +5V
10 Ground
11 No Connection
12 (SDA)
13 Horizontal sync (Composite sync)
14 Vertical sync
15 (SCL)

5

11

1

6

10

15

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3. Disassembly / Assembly Instructions

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AUDIO IN

SPEAKER

AC Outlet

Adaptor

Main Board

Inverter

ControlBrightness

TFT

LCD

Panel

Digital

Signal

Analog

Signal

Video Card

12V

12V

VA C

Volume control & Mute on/off

Speaker

Audio in

DC/DC

Converter

+5V

VLCD

+3.3V

+12V

Clamp

Video Gain

Video Level

ADC

MUX

Scaling

Engine

Sync detect

Phase calibration

OSD Generator

OSD overlay

MCU port

Dithering

Output control

Output

LCD

Panel

R, G, B

Sync

Buffer

U6

SYNCMOS

SM5964

MCU

HS

VS

HS

VS

U1 MRT

MASCOT

R, G, B offset

Gamma control

Audio amp.

4. Electronic Circuit Description

4-1 Block Diagram

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4-2 Main Board I/O Connections

P3 C

ONNECTION "INVERTER CONTROL"

Pin Description

1 N.C
2 CON
3 VEE
4 GND
5 VDD

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P5 CONNECTION "OSD CONTROL"

Pin Description

1 POW 1
2 GND
3 LED1
4 LED2
5 KEY1
6 KEY2
7 KEY3
8 KEY4

9 +
10 ­11 MUTE

4-3 Inverter Board I/O Connections

NOTE: MANUF ACTURER’S NAME MUST BE ON THE PRINTED SIDE FOR THE INVERTER BOARD TO

BE F A CING UP.

CON
VEE
GND
VDD

1

HV out
HV out

RTN
RTN

HV out

HV out

RTN
RTN

CN1

CN3

CN2

CN4

CN5

compatibles, Power PC and Macintosh. VG150m uses a TFT LCD panel with a 0.297mm pixel pitch,
provides 16.7 millions color images.

As the previous block diagram illustrates, VG150m uses a highly integrated solution (U1: Mascot V)
that combines a high performance ADC with an advanced image process controller. Using advanced
image scaling algorithms, Mascot V has intelligently adaptive sub-algorithms that will automatically
optimize the display quality for different images – the text is sharper and the graphics is smoother.

Furthermore, each TFT LCD monitor uses the 24LC02 (U14) chip to provide DDC1/2B¥ with
Analog Plug&Play, the DDC data format is EDID v1.3.

Digital process and control system allows users to control OSD menu values to change monitor
settings. The follow sections are major part discussions of the TFT LCD display control board.

POWER SYSTEM

This product uses an external power adapter to provide DC+12V. It is the source of other voltages +5VX,

3.3VX, and VLCD.

The voltage of +5VX is produced by regulator LM2596-5V (U5) and external components that can realize DC
to DC conversion from +12V to +5V. For some chips (MPU, ADC) that are sensitive to any voltage variance,
we need LDO 1084-3.3V (U11) to produce a stable voltage 3.3VX.

There is still an important consideration about power consumption. We must greatly reduce the power
consumption even up to 90% in power saving mode. So we need to switch off the power that needn’t exist
when the system enters to this mode. We use the P-channel MOSFET TRLML6402 (Q1) to control the on/off
state of the panel’s power VLCD.
See FIG1-1.

FIG1-1

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4-4 Theory of Circuit Operation

VG150m/mb is a multi-frequency and multi-mode color TFT LCD monitor. It supports different
resolutions including XGA, SVGA, VGA and other various high resolution up to 1024x768 for IBM, PC

ANALOG SIGNAL INPUT and EDID

This product uses the internal function of Mascot V (U1) as a signal detector in order to support separate SYNC.
The analog input Horizontal and Vertical Synchronal signals pass through the Schmitt trigger buffer U4 to stabilize

then input to

Mascot U1 pin38 VGA_VSYNC, pin39 VGA_HSYNC or pin40 SOGI and the image processing.

Then

Mascot will detect the signal type if it is separate SYNC, composite SYNC or SOG. MPU (U6) reads the

input signal type from IIC protocol and does the correct procedure to generate the proper signals to the whole
system.

24LC02 (U14) chip provide DDC1/2B¥ with Analog Plug&Play , and the DDC data format is EDID v1.3.
See FIG1-2.

FIG1-2

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ANALOG to DIGITAL CONVERSION and PROCESSING

General Description of Mascot

Mascot V is a highly integrated solution (U1) that combines a high performance ADC with an advanced image
process controller . Using a dvanced ima ge scaling alg orithms, Mascot V has i nte lligently adaptive sub -algo rithms
that will automatically optimize the display quality for different images – the text is sharper and the graphics is
smoother.
The build-in analog interface includes an 80MHz, 8-bit 3-channel ADC, pre-amplifier, and VGA, allowing
seamless support to resolution from VGA to XGA. ADC function block diagram, see FIG3-1.

FIG3-1 ADC Functional Block Diagram

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Clock Re-Generator Functional Block Diagram

FIG3-2 Clock Re-Generator

ADC Block Description

Variable Gain Amplifier (VGA)

The front-end circuit is designed to provide four major functions:
Provide AC coupled interface with single-ended R/G/B input signal, convert single-ended sign al to
differential signal, and define common mode voltage.
Define CLAMPING voltage level with respect to ground for image brightness control.
Perform user programmable precision gain amplification.
Provide low impedance differential driver for ADC.

Phase Locked Loop (PLL) and Multi-Phase Generation

The phase locked loop (PLL) generates desired ADC sampling cl ock frequency (30 MHz to 80 MHz) from
external line clock CKREF. The exact frequency is register programmable and rel ated to the input line clock
CKREF as follows:

Freq (PLL) = Freq (CKREF)* Ndiv <12:0>

To ease the graphic interface, a phase programmable output clock is also generated for external use. The exact
phase delay with respect to VCO output clock is register programmable and can be formulated as follows:

T

DELAY

= IJ+Tclk * phase<4:0> / 32

Where there is a systematic delay. Due to the periodic nature of the clock, user can practically program the ADC
sampling anywhere with respect to data in the step size of Tclk/32.

ADC

Based on the requirements for this ADC (high speed, low power and small size). The sub ranging architecture is
used to minimize the number of comparators. The interpolation technique is also used to reduce the number of
preamplifiers. Two ide ntical 8bit ADC converters are used to increase the throughput of sub ranging ADC to one
conversion per clock cycle.
Each ADC operates in two-step sub range, i.e. coarse (3 bits) and fine (5 bits). One to four interpolations is

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performed in fine conversion step to minimize the number of preamplifier and to improve differential non-linearity
errors (DNL). In addition, in order to prevent potential error occurred during coarse conversion, digital error
correction technique is also used.

Clock Re-Generator Functional Block Diagram

FIG3-3 Clock Re-Generator

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Host Interface Control

Host interface controller is an interface between Mascot V and an external CPU. The access to Mascot V internal
internal registers, SRAM, programmable fonts, gamma tables, and ROM is performed by interface controller.
Mascot V provides single read/write and incremental read/write. Mascot V supports I2C bus and SPI protocols.
The bus protocol selection is determined by pin CONFIG[4], and Mascot V slave address is determined by pin
CONFIG[3:0].

GPIO (General Purpose Input/Output)

Gerenal Purpose Input/Output
Mascot V has provided three pins for general purpose input/output(GPIO); these pins can be programmed
as input or output pins; each GPIO pin has three registers for programming: GPIO Input/output control register,
GPIO output data register and GPIO input register; When GPIO is programmed as output pin, GPIO Input/output
control register is programmed as I (output), and the output data is provided by GPIO output data register; When
programmed as input pin, GPIO Input/output control register is programmed as 0(input), the input value can be
accessed thrugh GPIO input register.

PWM (Pulse Width Modulation)

Mascot V has provided two sets of PWM, each PWM can generate programmable periodic square waves. The
generated wave consists of low period and high period. The low period and high period can be programmed
separately. Each period can be programmed to be 0Д255 basic cycles. The basic cycle is defined by design,
which also has four kinds of basic cycles can be chosen by programming.

Sync Processor

Sync Processor is used to detect input source (analog RGB or 24-bit RGB) and generate interruption to an
external CPU if input source changes. Then the CPU can program Mascot V correctly according to different input
sources. Sync Processor can generate interruption when there are frequency changes, Hsync and Vsync polarity
changes, and when there is no input signal. Sync processor provides h_counter and v_counter which are stored
in registers CR0B, CR0C, CR0D, and CR0E. V frequency can be calculated by (refclk/64) / v_counter or

187.5kHz/ v_counter for using 12MHz refclk. H frequency is calculated by (refclk/512k) * h_counter or 46.5Hz *
h_counter or 46.5Hz * h_counter for using 12MHz refclk.

Mascot V Sync Processor can also support composite Sync and sync-on-green inputs. If sync Processor detects
the input source is composite sync or sync-on-green input, Mascot V will separate composite sync or sync-on-green
to Hsync and Vsync.

Calibration

Calibration block performs position calibration, color calibration and phase calibration. In position calibration,
non-zero data are detected horizontally and vertically. The Left most and right most positions and their
corresponding pitch can be found.Also Horizontal Total & Vertical Total are calculated.
Color calibration includes maximum color component detection, co lor read back from specified position and
maximum color difference in 2 neighboring pixels.

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In maximum color calibration, the pixel which has the maximum color component (based on CRB1[3:0]) can be
found. In color read back calibration, the color component (based on CRB[3:0]) for specific position can be read
back. In maximum color difference calibration, for specific color component, color differences between every 2
neighboring pixels are compared from first till the last pair within a frame. The position which has the largest color
difference with its neighboring data is found.
Phase calibration can report pixel mismatch in up to 32 frames based on 2 specified points.

Capture Controller

Capture Controller is used to generate synchronization signals which are used for internal Mascot V. Within
Capture Controller block(FIG3-4), incoming data are processed, filtered, minimized and aligned with
controlling signals. Important internal synchronization signals in clude H_cnt, V_cnt, internal blank, and
end_of_frames.

FIG3-4 Capture Controller block

YUV to RGB Block

This block performs color space format conversion. Mascot V can convert 16 Bit YUV, RGB into 24 Bit RGB data
format.

Scaling Down

This block is used to conditionally drop incoming data if the incoming resolution is greater than 1024x768 which
is the physical resolution of the panel. A modified version of the Bresenham line-drawing algorithm is used to

determine which incoming data not to discard.

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Zoom Buffer

Zoom Buffer is used to store input data for scaling (zoom) function.

Zoom Buffer Write Control and Zoom Buffer Read Control

This Block generates write and read control signal to access zoom buffer.

Vertical Zoom Filter and Horizontal Zoom Filter

The

Mascot V scaling engine uses an advanced scaling technology and provides high quality scaling of text

images, graphic images and real-time video.

Display Control

FIG3-5 Display Control

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