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Service Manual
ViewSonic VG2427wm
Model No. VSXXXXX
23.6” Color TFT LCD Display
(VG2427wm_SM Rev. 1a Mar. 2009)
ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583
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Copyright Copyright © 2008 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,
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TABLE OF CONTENTS 1. Precautions and Safety Notices ......................................................................................... 4 2. Specification ....................................................................................................................... 7 3. Front Panel Function Control Description ....................................................................... 8 4. Circuit Description.................................................................
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1. Precautions and Safety Notices 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
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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 Surface of the LCD panel is pressed by fingers and that front cover of the monitor. Do not touch the surface of may cause “Mura.” the polarizer. Taking out the monitor by grasping the LCD panel. That Take out the monitor may cause “Mura.” 5
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Placing the monitor on foreign objects. That could Place the monitor on a clean and soft foam pad. scratch the surface of the panel or cause “Mura.” Place the monitor on the lap, the panel surface must The panel is placed facedown on the lap. That may be upwards. cause “Mura.” 6
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2. Specification 7
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3. Front Panel Function Control Description 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”. 8
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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
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Main Menu Controls Adjust the menu items shown below by using the up and down 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 ad
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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 1920 x 1080 @ 60Hz (recommended) means that the resolution is 1920 x 1080 and the refresh rate is 60 Hertz. Manual Image Adjust displays the Manual Image Adjust menu. H./V. Posi
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Language Select allows the user to choose the language used in the menus and control screens. 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 retu
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4. Circuit Description 4.1 Main Board U401 NT68667UFG/C The NT68667 is a highly integrated flat panel display controller that interfaces analog, digital, and video inputs. It combines a triple ADC, a DVI compliant TMDS receiver, a digital YUV receiver, a high quality zoom and shrink engine , a multi-color on screen display (OSD) controller , an advanced color engine , and many other functions in a single chip. It provides the user wit
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Pin Assignment 14
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U701 AP1117D33L and U704 AP1117E18LA: DC power convert, convert to 3.3v and 1.8v. AP1117 is a low dropout positive adjustable or fixed-mode regulator with 1A output current capability. The product is specifically designed to provide well-regulated supply for low voltage IC applications such as high-speed bus termination and low current 3.3V logic supply. AP1117 is also well suited for other applications such as VGA cards. AP1117 is guaranteed to have lower than 1.4V dropout at full l
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Pin Descriptions Name I/O Pin # Function A resistor divider from this pin to the Vout pin and ground sets the output voltage. Adj (GND) I 1 (Ground only for Fixed-Mode) The output of the regulator. A minimum of 10uF capacitor (0.15 Ω ≤ESR ≤20 Ω) Vout O 2 must be connected from this pin to ground to insure stability. The input pin of regulator. Typically a large storage capacitor (0.15 Ω ≤ESR ≤20 Ω) is connected from this pin to ground to insure that the input voltage do
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4.2 Power Board IC901 LD7576 The LD7576X series bring high performance, combines with highly integrated functions, protections and EMI-improve solution. It’s an ideal solution for those cost-sensitive system, reducing component count and overall system cost. The LD7576X series features near-lossless high voltage startup circuit, green-mode power-saving operation, leading-edge blanking of the current sensing and internal slope compensation. They also consist with more protections of O
