ViewSonic Vx2255wmb-2 Service Manual

							
 
 
ViewSonic VX2255wmb-2  VX2255wmh-2 
Model No. VS11661 
22” wide Color TFT LCD  Display 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
(VX2255wmb-2_VX2255wmh-2_SM Rev. 1a Apr. 2007) 
ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583 
Service Manual  
						

							
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ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
  VX2255wmh-2 
Copyright 
Copyright © 2007 by ViewSonic Corporation.    All rights reserved.    No part of this publication 
may be reproduced, transmitted, tran scribed, 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 ot herwise, 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 
Optiquest is a registered trademar k of ViewSonic Corporation. 
ViewSonic is a registered trademar k of ViewSonic Corporation. 
All other trademarks used within this document ar e the property of their respective owners. 
 
Product disposal at end of product life 
The lamp in this product contains mercury. Pleas e dispose of in accordance with local, state or 
federal laws. 
 
Revision History 
Revision  SM Editing Date  ECR Number  Description of Changes  Editor 
1a  4/24/2007      Initial Release  Jamie Chang 
       
       
       
       
       
        
						

							
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ViewSonic Corporation 
Confidential - Do Not Copy    VX2255wmb-2 
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TABLE OF CONTENTS 
 
 
1.  Precautions and Safety Notices  1 
2. Specification   4 
3.  Front Panel Function Control Description    13 
4. Circuit Description  19 
5. Adjusting Procedure 41 
6.  Trouble Shooting Flow Chart 53 
7. Block Diagrams  62 
8. Schematic Diagrams  63 
9.  PCB Layout Diagrams   69 
10.  Exploded Diagram And Spare Parts List  73 
11.  Recommended Spare Parts List   78 
 
  
						

							
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1. Precautions and Safety Notices 
 
1. SAFETY PRECAUTIONS 
This monitor is manufactured and tested on a  ground principle that a user’s safety comes 
first. However, improper used or installation may cause damage to the monitor as well as to 
the user. 
WARNINGS:  z This monitor should be operated only at th e correct power sources indicated on the 
label on the rear of the monito r. If you’re unsure of the power supply in you residence, 
consult your local dealer or Power Company. 
z  Use only the special power adapter that comes with this monitor for power input. 
z  Do not try to repair the monitor by yourself,  as it contains no user-serviceable parts. 
Only the qualified technician can repair it. 
z  Do not remove the monitor cabinet. There are  high-voltage parts inside that may cause 
electric shock to human bodies. 
z  Stop using the monitor if the cabinet is damaged. Have it checked by a service 
technician. 
z  Put your monitor only in a lean, cool, dry  environment. If it gets wet, unplug the 
power cable immediately and  consult your closed dealer. 
z  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. 
z  Do not place heavy objects on the monitor or power cord. 
2.  PRODUCT SAFETY NOTICE 
Many electrical and mechanical parts in this ch assis have special safety visual inspections 
and the protection afforded by them cannot ne cessarily be obtained by using replacement 
components rated for higher voltage, watta ge, etc. Before replacing any of these 
components read the parts list in this manua l carefully. The use of substitute replacement 
parts, which do not have the same safety charac teristics as specified in the parts list, may 
create shock, fire, or other hazards. 
3.  SERVICE NOTES 
z   When replacing parts or circ uit boards, clamp the lead wires around terminals before 
soldering. 
z   Keep wires away from high voltage, high te mperature components and sharp edges. 
z   Keep wires in their original posi tion so as to reduce interference. 
z   Adjustment of this product please refers to the user’ manual.  
						

							
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4 Handling and Placing Methods  
						

							
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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2. Specification 
INTRODUCTION 
FEATURES VX2255wmb/wmh-2 
Size 
22 wide 
Luminance (Typ) 300 cd/㎡ 
Contrast Ratio (Typ)  1000:1 
Colors 16.7 M  (6 bits + 2 bits FRC) 
Response Time   5 ms(on/off) 
Viewing Angle (H/V)  170° / 160 ° 
TFTLCD PANEL 
1st  
Recommend resolution  1680x1050@60Hz 
Analog  Yes (75ohms, 0.7/1.0 Vp-p) Input Signal 
Digital Yes 
Separate Sync   Yes 
Composite Sync  Yes Sync Compatibility 
Sync on Green  Yes 
PC Yes  
Power Mac Yes Compatibility 
TV Box  Yes 
Power Voltage  AC 100-240V, 50/60Hz  Yes 
On Mode(Typ) < 45 W (without audio) Power Consumption 
Off Mode (Max)  ≦1 W 
Audio  2W / THD 10% (Max)  Yes 
WebCam 1.3M / USB2.0 / Windows XP 
Cable (type A to type B)  Yes 
Tilt ( 20 
° - -5 ° )  Yes 
Swivel 
360° 
Pivot No Ergonomics 
Height Adjust  80mm 
OSD Control [ 1 ] [▲] [▼ ] [ 2 ] // [] Yes 
Physical (W x H x D) 528(W) x 450(H) x 225(D) mm Dimension 
Package (W x H x D) 572(W) x 525(H) x 267(D) mm 
Physical (Net Weight)  6.0 Kg /  13.3 lbs Weight 
Package (Gross Weight)  8.4 Kg  / 18.6 lbs 
Temperature (℉/℃ )  32℉
-104 /℉+0℃-+40℃  Operating Condition 
Humidity (%)  10 % - 90 % 
Temperature (℉/℃ )  -4
℉ -140 / ℉-20 ℃-60 ℃ Storage Condition 
Humidity (%)  10 % - 90 % 
Regulation Global: CB, MPR II,WEEE,ROHS 
VSA:UL, cUL, FCC-B, TUV-S, NOM, Energy Star 
VSE:TUV/ERGO(covers ISO13406-2&MPR II), TUV/GS,CE  
         GOST-R+Hygienic ,SASO , ENERGY, Ukraine 
VSI: BSMI, PSB, C-TICK, MIC, VCCI, Green Mark 
VSCN:CCC 
  
						

							
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 2-1 GENERAL specification 
Test Resolution & Frequency  1680x1050@ 60Hz 
Test Image Size Full Size 
Contrast and Brightness Controls  Factory Default:   
Contrast = 70%, Brightness = 100% 
 
2-2 VIDEO INTERFACE 
Analog Input Connector  DB-15 (Analog), refer the appendix A 
Digital Input Connector  DVI-D 
Audio input 1  3.5Mini Jack 
Headphone output 3.5Mini Jack 
Default Input Connector  Defaults to the first detected input 
Video Cable Strain Relief Equal to twice the weight of the monitor for five 
minutes 
Video Cable Connector DB-15 
Pin out Compliant DDC/CI / DDC/2B 
Video Signals 1. Video RGB (Analog) 
Separate, Composite, and Sync on Green 
2. TMDS (Digital) 
Video Impedance 
75 Ohms (Analog), 100 Ohms (Digital) 
Maximum PC Video Signal  950 mV with no damage to monitor 
Maximum Mac Video Signal  1250 mV with no damage to monitor 
Sync Signals TTL 
DDC/2B Compliant with Revision 1.3 
DDC/CI Compliant with Revision 1.1 
HDCP  HDCP code inside and compatible 
Sync Compatibility  Separate Sync, Composite Sync, SOG 
Video Compatibility Shall be compatible with all PC type computers, 
Macintosh computers, and after market  video cards
640x350 640x400 640x480 720x400 
720x480 800x600 832x624 1024x768 
1152x864 1152x870 1280x720 1280x768 
1280x960 1280x1024 1360x768 1400x1050
1440x900 1600x1200 1680x1050  
Resolution Compatibility 
The image vertical size might not be full screen.  
But the image vertical position should be at the 
center. 
Exclusions  Not compatible with interlaced video 
  
						

							
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2-3 POWER SUPPLY 
Internal Power Supply  Part Number: 790961400600R  
INPUT VOLTAGE RANGE  AC90~264 (Worldwide) 
Input Frequency Range  47  to 64 Hertz 
Short Circuit Protection Output can be shorted without damage 
Over Current Protection 3.3~4.5A  typ. at 5 VDC  
( Protect when short circuit ) 
Leakage Current 
3.5mA (Max) at 264VAC / 50Hz 
EFFICIENCY 80 % typical at 115VAC Full Load 
Fuse  Internal and not user replaceable 
Power Dissipation 
< 45 Watts (typ) (WITHOUT AUDIO) 
Max Input AC Current  1.6A (max) 
INRUSH CURRENT  
(COLD START) 80 A Max./ 240VAC / 50Hz   
(Cold Start at 25 ℃,Full Load) 
Power Supply Cold Start 
Shall start and function properly when under full load, with all 
combinations of input voltage, input frequency, and operating 
temperature 
Power Supply Transient Immunity Shall be able to withstand an ANSI/IEEE C62.41-1980 6000V 200 
ampere ring wave transient test with no damage 
Power Supply Line Surge 
Immunity Shall be able to withstand 1.5 times nominal line voltage for one 
cycle with no damage 
Power Supply Missing Cycle 
Immunity  Shall be able to function properly, without reset or visible screen 
artifacts, when ½ cycle of AC power is randomly missing at 
nominal input 
Power Supply Acoustics 
The power supply shall not produce audible noise that would be 
detectable by the user.  Audible shall define to be in compliance 
with ISO 7779 (DIN EN27779:1991) Noise measurements of 
machines acoustics. Power Switch noise shall not be considered 
US Type Power Cable  
Color = Black  Separate 3-prong NEMA 5-15P type plug.  Length = 1.8m. 
Connects to display. 
European Type Power Cable 
Color = Black Schuko CEE7-7 type plug. 
Length = 1.8m, Connects to display.  
CCC Type Power Cable  
Color = Black Separate 3-prong type plug.   
Length = 1.8m. Connects to display. 
PSE Type Power Cable 
Color = Black Separate 2-prong NEMA 1-15P type plug.   
Length = 1.8m. Connects to display. 
Power Saving Operation(Method)  VESA DPMS Signaling 
Power Consumption On Mode 
						

							
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2-4 ELECTRICAL REQUIREMENT 
Horizontal / Vertical Frequency 
Horizontal Frequency  24 – 82 KHZ  
Vertical Refresh Rate  50 – 85* HZ 
Maximum Pixel Clock  165MHz, 
Sync Polarity Independent of sync polarity. 
 
Timing Table 
Analog 
Item Timing 
Separate 
Composite  SOG 
Digital - TMDS 
Remark 
1  640 x 350  @  70  Hz,  32  kHz V V V V
  
2  640 x 400  @  60  Hz,  32  kHz V V V V   
3  640 x 400  @  70  Hz,  32  kHz V V V V   
4  640 x 400  @  85  Hz,  38  kHz V V V V   
5  640 x 480  @  50  Hz,  25  kHz V V V V   
6  640 x 480  @  60  Hz,  32  kHz V V V V   
7  640 x 480  @  67  Hz,  35  kHz V V V V   
8  640 x 480  @  72  Hz  38  kHz V V V V   
9  640 x 480  @  75  Hz,  38  kHz V V V V   
10  640 x 480  @  85  Hz,  43  kHz V V V V   
11  720 x 400  @  70  Hz,  32  kHz V V V V   
12  720 x 400  @  85  Hz,  38  kHz V V V V   
13  720 x 480  @  60  Hz,  29.8  kHz V V V V   
14  720 x 576  @  50  Hz,  31.3  kHz V V V V   
15  800 x 600  @  56  Hz,  35.1  kHz V V V V   
16  800 x 600  @  60  Hz,  38  kHz V V V V   
17  800 x 600  @  72  Hz,  48  kHz V V V V   
18  800 x 600  @  75  Hz,  47  kHz V V V V   
19  800 x 600  @  85  Hz,  54  kHz V V V V   
20  832 x 624  @  75  Hz,  50  kHz V V V V   
21  1024 x 768  @  50  Hz,  40  kHz V V V V   
22  1024 x 768  @  60  Hz,  48  kHz V V V V   
23  1024 x 768  @  70  Hz,  57  kHz V V V V   
24  1024 x 768  @  72  Hz,  58.1  KHz V V V V   
25  1024 x 768  @  75  Hz,  60  KHz V V V V   
26  1024 x 768  @  75  Hz,  60.2  KHz V V V V   
27  1024 x 768  @  85  Hz,  69  KHz V V V V   
28  1152 x 864  @  75  Hz,  68  KHz V V V V   
29  1152 x 870  @  75  Hz,  69  KHz V V V V   
30  1152 x 900  @  67  Hz,  62.5  KHz V V V V   
31  1280 x 720  @  50  Hz,  37  KHz V
XXV
  
32  1280 x 720  @  60  Hz,  45  KHz V V V V   
33  1280 x 768  @  50  Hz,  40  KHz V V V V   
34  1280 x 768  @  60  Hz,  47.8  KHz V V V V   
35  1280 x 768  @  75  Hz,  60  KHz V V V V   
36  1280 x 768  @  85  Hz,  69  KHz V V V V   
37  1280 x 960  @  50  Hz,  49  KHz V V V V   
38  1280 x 960  @  60  Hz,  60  KHz V V V V   
39  1280 x 960  @  75  Hz,  75  KHz V V V V   
40  1280 x 1024  @  50  Hz,  53  KHz V V V V   
41  1280 x 1024  @  60  Hz,  64  KHz V V V V   
42  1280 x 1024  @  75  Hz,  80  KHz V V V V   
43  1360 x 768  @  60  Hz,  48  kHz V V V V  
44  1400 x 1050  @  50  Hz,  54  kHz V V V V   
45  1400 x 1050  @  60  Hz,  65.3  kHz V V
XVFor analog sync,  
Switch 1400 x 1050@60Hz and 1680 x