ViewSonic VA1903wb, VA1903wm, VS11618 Schematic

Service Manual

ViewSonic VA1903wb/VA1903wm

Model No VS11618

19” Color TFT LCD Display

Manufacture Date: Dec-25-06

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Copyright © ViewSonic Macintosh and Power Macintosh are registered trademarks of Apple Computer, Inc. Microsoft, Windows, Windows NT, and the Windows logo are registered trademarks of Microsoft Corporation in the United States and other countries. ViewSonic, the three birds logo, OnView, ViewMatch, and ViewMeter are registered trademarks of ViewSonic Corporation. VESA is a registered trademark of the Video Electronics Standards Association. DPMS and DDC are trademarks of VESA.

ENERGY STAR (EPA). As an ENERGY STAR product meets the ENERGY STAR

Disclaimer: ViewSonic Corporation shall not be liable for technical or editorial errors or omissions contained herein; nor for incidental or consequential damages resulting from furnishing this material, or the performance or use of this product. In the interest of continuing product improvement, ViewSonic Corporation reserves the right to change product specifications without notice. Information in this document may change without notice. No part of this document may be copied, reproduced, or transmitted by any means, for any purpose without prior written permission from ViewSonic Corporation.

any language or manual or otherwise, without the prior written permission of ViewSonic Corporation.

is a registered trademark of the U.S. Environmental Protection Agency

partner, ViewSonic Corporation has determined that this

guidelines for energy efficiency.

Revision History

Revision Date Description of changes Approval

A00 Dec-25-06 Initial Release YG.WANG

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TABLE OF CONTENTS

1. Precautions And Safety Notices 4

2. Specification 7

3. Front Panel Control And Indicators 9

4. Circuit Description 15

5. Adjustment Procedure 25

6. Troubleshooting Flow Chart 44

7. Recommended Spare Parts List 45

8. Exploded Diagram And Spare Parts List 60

9. Disassemble Process 64

10. Block Diagram 69

11. Schematic Diagram 70

12. PCB Layout Diagram 79

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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

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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

Type

19.0” (full 19” wide viewable diagonal area), TFT(Thin Film Transistor),Active Matrix WXGA+ LCD

Color Filter RGB vertical stripe

Glass Surface Anti-Glate

Input Signal Video Sync

RGB analog(0.7/1.0 Vp-p, 75ohms) Separate Syic, Fh:24-82 kHz, Fv:50-75 Hz

Compatibility PC

Macintosh

Resolution Recommended

and supported

Up to 1440 x 900 Non-interlaced Power Macintosh up to 1440 x 900

1440 x 900 @ 60, 75 Hz 1280 x 1024 @ 60, 75 Hz 1024 x768 @ 60, 70, 72, 75 Hz 800 x 600 @ 56, 60, 72, 75 Hz 640 x 480 @ 60, 75 Hz 720 x 400 @ 70 Hz

Power Voltage 100V~240 VAC, 50/60Hz (auto switch) 1.2A

Display area Full Scan

408.24mm(H) x 255.15mm(V)

16.07”(H) x 10.04”(V)

Operating conditions

Storage conditions

Temperature Humidity Altitude

32°F to + 104°F( 0°C to + 40°C) 10%C to + 90%(non-condensing) To 10,000 feet

-4°F to + 104°F( -20°C to + 60°C) 10%C to + 90%(non-condensing) To 40,000 feet

Weight Physical 10.41b(4.7 kg)

BSMI, CCC, PSB, C-Tick, VCC1,

Regulations

Power saving modes

On Off

CE, GS, Ergo, Gost-R/Hygienc, SASO, TCO’03, UL/cUL, FCC-B, ICES-B, TUV-S, ENERGY STAR

Normal (green LED) <2W (orange LED)

Preset Timing Mode (pre-adjusted to VESA® 1440 x 900 @ 60 Hz) Warning: Do not set the graphics card in your computer to exceed these refresh rates;

doing so may result in permanent damage to the LCD display.

Macintosh computers older than G3 require a ViewSonic® Macintosh adapter. To order an

adapter, contact ViewSonic.

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2.2 INTERFACE DESCRIPTION

D-SUB 15 PIN CONNECTOR

11 15

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 co n nection

12 (SDA)

13 Horizontal sync (Composite sync)

14 Vertical sync

15 (SCL)

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Front Panel Function Controls And Indicators

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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.)

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. (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

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（For VA1903wm only） Volume 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).

and down buttons.

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. Enabing the intended. Enabling the sRGB setting will cause 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.

User Color Individual adjustments for red (R), green (G), and blue (B).

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1. To select color (R, G or B) press button [2].

2. To adjust selected color, press

▼

and ▲. 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 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.

Fine Tune sharpens the focus by aligning text and/or graphics with pixel boundaries.

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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]

[▼]

[▲]

[▼] + [▲]

[1] + [2]

Input toggle（Analog or Digital；refer to Appendix D）

Contrast adjust

recall both of Contrast and Brightness to default

toggle 720x400 and 640x400 mode when input 720x400 or 640x400 mode

[1] + [▼] + [▲] White Balance (Not shown on user’s guide)

[1] + [▼]

[1] + [▲]

Power Lock

OSD Lock

No signal + [2] + [ ] Burning mode

Signal + [2] + [ ] Factory mode

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

CCFL Drive.

Power Board

(Include: adapter, inverter)

100V-240V

AC-IN

Key Board

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

EPROM

Main Board

EPROM

Flat Panel and CCFL backlight

HOST Computer

PWPC board

TSUM16AL-1

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

Bridge Rectifier and Filter

Transformer

Rectifier CMOS

Start Circuit R931, R904,R938

Lamp

OSC and Output Circuit

Feedback Circuit

PWM

Control IC

Over Voltage

DC Convert Circuit

MOSFET Q805,Q806

PWM Control IC

Over Vol tage Protect

12V

ON/OF

ON/OFF Control

DIM

CN902

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4.4 INTRODUCTION OF IC

TSUM16AL-1(U401): integrate ADC, OSD, SCALER, MCU, LVDS, convert analog RGB

into digital and room and shrink scaling output to LCD panel.

Pin Diagram:

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PIN Function:

Pin Symbol Description

37 SDO SPI flash serial data output 38 CSZ SPI flash chip select 39 SCK SPI flash serial select 40 SDI SPI flash serial data input 30 DDCA_SDA/RS232_TX DDC data for analog interface; 4mA driving

strength/UART transmitter/GPIO

31 DDCA_SDA/RS232_RX DDC data for analog interface/UART

transmitter/GPIO 84 RST Chip reset; High reset 87 RSTN Chip reset; Low reset 81 VCTRL Regulator control 27 HSYNCO Analog HSYNC input 28 VSYNCO Analog VSYNC input 26 REFP Internal ADC top de-coupling pin 25 REFM Internal ADC bottom de-coupling pin 15 REXT

External resistor 390 ohm to AVDD＿ADC 86 PWM1/GPIO_P25 Pulse Width Modulation Output; 4mA driving

strength/General Purpose Input/Output; 4mA

driving strength 93 PWM0 Pulse Width Modulation Output; 4mA driving

strength/General Purpose Input/Output; 4mA

driving strength 80 BYPASS For External Bypass Capacitor 96 XIN Xin; Crystal Oscillator Input 97 XOUT Xout; Crystal Oscillator Output

8、14、24 AVDD＿ADC

16 98

32、49、56、

34、51、66、

AVDD＿PLL

AVDD＿MPLL

VDDP Digital Output Power 3.3V

VDDC Digital Core Power 1.8V

ADC Power 3.3V

PLL Power 3.3V

MPLL Power 3.3V

AP1117E33LA (U701): DC power convert, used to 5v convert 3.3v.

AP1117E18LA(U702): DC power convert, used to 5v convert 1.8v.

Pm25LV512A/010A/020/040(U402): The PM25LV010 are 512 Kbit/1 Mbits/2 Mbit/4

Mbit3.0 Volt-only Serial Peripheral Interface(SPI) Flash memories. The devices are designed to support 33MHz fastest clock rate in the industry in normal read mode, 100MHz in fast read mode and the bottom 4Kbyte sector into four smaller 1 Kbyte sectors features(except Pm25LV512A), The devices use a single low voltage, ranging from 2.7 Volt to 3.6 Volt, power supper to perform read, erase

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and program operations. The devices can be programmed in standard EPROM programmers as well.

Pin Diagram:

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.

SO OUTPUT Serial Data Output

WP# INPUT Write Protect A hardware program/erase protection for all or

partial of memory array. When the WP# pin is pulled t low, whole or partial of memory array is write protected depends on the setting of BP2, BP1 and BP0 bits in the Status Register, When the WP# is pulled high, the devices are not write protected.

GND Ground

Vcc Device Power Supply

HOLD# INPUT Hold: Pause serial communication with the master device

without resetting the serial sequence.

SCK INPUT Serial Data Clock

SI INPUT Serial Data Input

Circuit Diagram

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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

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PIN Function

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:

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PIN Descriptions:

Pin Name Function

1 RT

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

2 COMP

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 8 HV

current for the 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

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:

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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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5. Adjustment Procedure

5.1 ADJUSTMENT CONDITIONS AND PRECAUTIONS

1. Approximately 30 minutes should be allowed for warm up before proceeding.

2. Adjustments should be undertaken only on those necessary elements since most of them have been carefully preset at the factory.

3. ESD protection is needed before adjustment.

5.2 MAIN ADJUSTMENTS

NO. FUNCTIONS DESIGNATION

1. White Balance Function Key

2. Geometry Function Key

5.3 ALIGNMENT PROCEDURES

Approximately 30 minutes should be allowed for warm up before proceeding White-Balance adjustment.

1. Adjust of White Balance

1.)How to do the Chroma-7120 MEM .Channel setting

A、Reference to chroma 7120 user guide B、Use “ SC” key and “ NEXT” key to modify xyY value and use “ID” key to modify the TEXT description Following is the procedure to do white-balance adjust

2.)Setting the color temp. You want

A、MEM.CHANNEL9 ( 9300 color): 9300 color temp. parameter is Wx = 0.283 ±0.03;Wy = 0.298 ±0.03;

Y = 250 ±20 cd/m

B、MEM.CHANNEL10 ( 6500 color):

6500 color temp. parameter is Wx = 0.313±0.03;Wy = 0.329 ±0.03; Y = 260 ±20 cd/m

C、MEM.CHANNEL 11 ( 5400 color):

5400 color temp. parameter is Wx = 0.335±0.03;Wy = 0.350 ±0.03; Y = 250 ±20 cd/m

D、MEM.CHANNEL10 ( SRGB color):

6500 color temp. parameter is Wx = 0.313±0.03;Wy = 0.329 ±0.03; Y = 220 ±20 cd/m

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3.)Into factory mode of VA1903wb/VA1903wm

A、First Power off, then press Switch 2 button along with press Power button will activate

the factory mode, then MCU will do AUTO LEVEL automatically. Meanwhile press MENU the OSD screen will located at LEFT TOP OF PANEL.

4.)Bias adjustment :

Set the Contrast

Adjust the Brightness

to 70

to 100.

5.)Gain adjustment : Move cursor to “-F-” and press MENU key

A、Adjust 9300 color-temperature

(1)、Switch the Chroma-7120 to RGB-Mode (with press “MODE” button ) (2)、Switch the MEM. channel to Channel 9 ( with up or down arrow on chroma 7120 ) (3)、The LCD-indicator on chroma 7120 will show x = 0.283 ±0.03, y =0.298 ±0.03,

Y = 250 ±20 cd/m

(4)、Adjust the RED of color1 on factory window until chroma 7120 indicator reached

the value R=100

(5)、Adjust the GREEN of color1 on factory window until chroma 7120 indicator reached

the value G=100

(6)、Adjust the BLUE of color1 on factory window until chroma 7120 indicator reached

the value B=100

(7)、Repeat above procedure ( item 4,5,6) until chroma 7120 RGB value meet the

tolerance =100±5

B、Adjust 6500 color-temperature

(1)、Switch the chroma-7120 to RGB-Mode (with press “MODE” button ) (2)、Switch the MEM .channel to Channel 10( with up or down arrow on chroma 7120 ) (3)、The LCD-indicator on chroma 7120 will show x = 0.313 ±0.03, y = 0.329 ±0.03, Y =

260 ±20 cd/m

(4)、Adjust the RED of color3 on factory window until chroma 7120 indicator reached

the value R=100

(5)、Adjust the GREEN of color3 on factory window until chroma 7120 indicator reached

the value G=100

(6)、Adjust the BLUE of color3 on factory window until chroma 7120 indicator reached

the value B=100

(7)、Repeat above procedure ( item 4,5,6) until chroma 7120 RGB value meet the

tolerance =100±5

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