ViewSonic VA902 Service Manual

Model No. VS1078019” Color TFT LCD DisplayService ManualViewSonic VA902/bViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-858

Button “Key-2” is defined as two functions of selecting and adjustment

T1 (ms) T2 (ms) T3 (ms) T4 (ms) T5 (ms) T6 (ms) T7 (ms) 0.1~10

6.4 CN103 (Connect I/F BD to panel, FI-X30S-H or Equivalent) Pin No.

7. Key Parts Pin Assignment 7.1 IC802 (TOP246Y, Power Control IC) Pi

Pin Symbol I/O Description 20GNDGround21 VDDP O Digital Output Pow

Pin Symbol I/O Description 74 PWM1 O PWM1; 4mA driving strength 75 NC Not connected76 NC Not connected 77 AD1 I/O DDR direct bus AD1; 8

Pin Symbol I/O Description 119 LVB3M O B-Link Negative LVDS Differential Data Output 120 LVBCKP O B-Link Positive LVDS Differential Clock Outp

7.4 U105 (Micro-controller: W78E65P-40) Pin Symbol I/O Description

ModelTitleDate Rev:ViewSonic Corporation 15ViewSonic Corporation Confidential - Do Not Copy VA902/b4. Disassembly & Assembly1. Exploded Dia

ViewSonic Model Number: VS10780-1WRev: 1aSerial No. Prefix: PSS / PSWItem ViewSonic P/N Ref. P/N Description Q'ty1 C-00003659/C-00003677 71403000

CopyrightCopyright¤ 2005 by ViewSonic Corporation. All rights reserved. No part of this publication may bereproduced, transmitted, transcribed, stor

2. Disassembly Block NOTE: The arrow is the direction of disassembly. HINGE COVER*2 BEZEL SUB-ASSM *1 (SCREW,P,

3. Assembly Block . NOTE: The arrow is the direction of assembly. CHASSIS*1 INSULATOR,MYLAR*1

5. TEST AND ADJUSTMENT 1. Key Function Description CONTROL KEY KEYS FUNCTION [AUTO] [2] By pressing [AUTO] key, “Auto Image Adjust” is performed

3. OSD Control 3.1 OSD table Layer 1 Layer 2 Layer 3 Auto Image Adjust Contrast (+ / -) Contrast/Brightness Brightness (+ / -) Srg

3.3 Power lock Menu function Power Lock Menu Function Check Item Method Phenomenon Activate Power Lock [1] + [▼] 10S

6. EDID (Rewrite EDID data to EEPROM) If we need to rewrite the EEPROM data, please confirm the following steps. 1. Plug in VGA Cable; we can rewrit

8 After repair, to ensure the quality you should do the following test and adjustment Item Content Equipment Test OSD function 1.Signal is set as

6. TROUBLE SHOOTING 1. Common Acknowledge z If you change the interface board, be sure that the U105, U106 and U103 these three components also

2. No Power & Power LED Off

3. DC output voltage is unstable Output Voltage Unstable Check Vbe of Q801 below 0.3V Check circuit if short Check ZD801, ZD802, ZD803, D8

TABLE OF CONTENTS 2. Service Tools & Equipment Required3. Circuit Theory4. Disassembly & Assembly6. Troubleshooting9. PCB Layout Diagrams7.

4. Output power is unstable Unstable power Check sampling Circuit Check R810, R8

5. Backlight can’t be turned on Is there high-level voltage on pin8 of IC501? Is t

6. Black Screen and backlight turn on 29ViewSonic Corporation Confidential - Do Not Copy VA902/b

7. White Screen White ScreenWorkmanshipLVDS Cable ReinsertChange LVDS CableCheck VLCD is 5VCheck Panel-Enable ofU105(pin2) is lowLVDS Cable NGCheck

8. Bad Screen Bad ScreenWorkmanshipLVDS Cable NG1.CheckX101,C154,C1552.CheckX102,C126,C168Check ALE/RDZ/WRZ/AD0/AD1/AD2/AD3/HWRESETCheck the pins

Rev: 1aSerial No. Prefix: PSSItem ECR/ECN ViewSonic P/N Ref. P/N Location Universal number# Q'ty1 Power Cord (Australia) A-00003671 453070800420R

Rev: 1aSerial No. Prefix: PSWItem ECR/ECN ViewSonic P/N Ref.P/N Location Universal number# Q'ty1 Power Cord (Australia) A-00003671 453070800420R

Rev: 1aSerial No. Prefix: PSSItem ViewSonic P/N Ref. P/N Description Location1 #N/A 506250005001 LBL,AGENCY(VA902), LE1909.CCC MARK For VSCN &VSI

Item ViewSonic P/N Ref. P/N Description Location Qty.60 #N/A 506102000400LOGO PLATE,VIEWSONIC, LE1709(THREEBIRDS) For VSCN &VSI & VSE &VSE

Rev: 1aSerial No. Prefix: PSWItem ViewSonic P/N Ref. P/N Description Location1 #N/A 506250005001 LBL,AGENCY(VA902), LE1909.CCC MARK For VSA 1 PC2 #N/A

1. Appropriate Operation (1) Turn off the product before cleaning. (2) Use only a dry soft cloth when cleaning the LCD panel surface. (3) Use a so

Item ViewSonic P/N Ref. P/N Description Location Qty.61 #N/A 506380002100TAPE,WRAPPINGTYPE(VIEWSONIC),50mmx75M,LE1709 For VSA 0.0083 ROL62 #N/A 506431

38ViewSonic Corporation Confidential - Do Not Copy VA902/b 8. SCHEMATIC DIAGRAMPower Supply R824510KZD8035.6VR8233M3R8183K3 1%R8166R8ON/OF

39ViewSonic Corporation Confidential - Do Not Copy VA902/b Inverter +14VC5112.2uF/25VR5130R D502BAV991231.4KQ5012N7002132D5121N4148WIS3C5

40ViewSonic Corporation Confidential - Do Not Copy VA902/b DC Input R10610KVLCDBRIGHTNESSVCC3.3VAA1VCC5V+C106100uF/16VQ103PMBT3904VCC5VC108

41ViewSonic Corporation Confidential - Do Not Copy VA902/b VGA Input R11275 1%C165NCD103SN4148HPD_VGADDC_SDA_VGANC/C118 1000P/50VR121 47R

42ViewSonic Corporation Confidential - Do Not Copy VA902/b Scaler AD3C1710.1/50VVPLLPA8C1320.1/50VPB0C1350.1/50VPB1FB102BEAD60OHMPB3PA5C1

43ViewSonic Corporation Confidential - Do Not Copy VA902/b Panel Interface PB6RXE1-RXO1-PB1RXO0-PB[0..9]RXE0-PA7RXE2+RXO0-PA5PA2RXO3-RXEC-R

44ViewSonic Corporation Confidential - Do Not Copy VA902/b MUC U105Winbond W78E65P12345672021222425262728293032353637383940111314161741424

45ViewSonic Corporation Confidential - Do Not Copy VA902/b Key Pad POWER DOWNSW101SW TACTLED_ORANGEKEY_UPSW102SW TACTUPKEY_SELECT/AUT

46ViewSonic Corporation Confidential - Do Not Copy VA902/b 9. PCB Layout Main board Top layout

(11) After installation of the TFT Module into an enclosure (LCD monitor housing, for example), do not twist orbend the TFT Module even momentarily. W

47ViewSonic Corporation Confidential - Do Not Copy VA902/b POWER board

*Readers Response*Dear Readers:Thank you in advance for your feedback on our Service Manual, which allows continuous improvementof our products. We w

2. SERVICE TOOLS & EQUIPMENT REQUIRED 1. SIGNAL GENERATOR 2. MU

3. CIRCUIT THEORY 1. Block Diagram XTAL122.118MHzTOP246YOPP/OCPLDO5V

2. Electronic Circuit Theory 2.1 Switching Mode Power Supply 2.1.1 AC Current Input Circuit P801 is a connector for connecting AC Power. F801 is a

dimming frequency is determined by R527 and C506. C502 is used for soft