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Iiyama AS3921U Service Manual
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Iiyama AS3921U Service Manual

Iiyama AS3921U Service Manual

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Contents
SERVICE MANUAL
AS3921U
1. REPLACING THE BACKLIGHT
2. SET-UP ADJUSTMENTS
3. CIRCUIT DESCRIPTION
4. SERVICE PARTS LIST
5. EXPLODED VIEW
6. DIAGRAMS

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Summary of Contents for Iiyama AS3921U

  • Page 1 Contents SERVICE MANUAL AS3921U 1. REPLACING THE BACKLIGHT 2. SET-UP ADJUSTMENTS 3. CIRCUIT DESCRIPTION 4. SERVICE PARTS LIST 5. EXPLODED VIEW 6. DIAGRAMS...

  • Page 2: Service Manual

    NO. S1500E04 Revision SERVICE MANUAL October 27, 2000 AS3921U Copyright Iiyama Corporation 710-1 Kitaowaribe, Nagano-shi 381-0014 JAPAN...
  • Page 3 [ Revision Record ] Rev. Section Contents...

  • Page 4: Table Of Contents

    CONTENTS - Page- i - ii SAFETY PRECAUTION ................... 1. REPLACING THE BACKLIGHT ..............2. SET-UP ADJUSTMENTS ................2 - 5 3. CIRCUIT DESCRIPTION ................6 - 9 4. SERVICE PARTS LIST ................10 - 25 5. EXPLODED VIEW ..................26 - 38 6.

  • Page 5: Safety Precaution

    š SAFETY PRECAUTION › 1. The design of this product contains special hardware, many circuits and components specially for safety purposes. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Service should be performed by qualified personnel only.
  • Page 6 Alternate Check Method Plug the AC line cord directly into the AC outlet (do not use a line isolation transformer during this check.). Use an AC voltmeter having 1,000 ohms per volt or more sensitivity in the following manner. Connect a 1,500Ω 10W resistor paralleled by a 0.15uF AC-type capacitor between an exposed metal part and a known good earth ground (water pipe etc.).

  • Page 7: Replacing The Backlight

    1. REPLACING THE BACKLIGHT Note: Replacing the Backlight should be performed by qualified personnel only. <Replacement procedure> LCD module Separate the LCD module from the chassis. (See Figure 1) Refer to ASSY-LCD in 5. EXPLODED VIEW for taking LCD panel apart. Pull down A Stopper toward A with –...

  • Page 8: Set-Up Adjustments

    Headphones CD player Audio-LR confirmation equipment USB compliant computer Short-connector for LCD (Iiyama handmade) <Preparation> Connect the signal cable from the signal generator to the monitor. Adjustment data is automatically saved in the memory when the on screen display disappears.
  • Page 9 LOCK OUT FACILITY User adjustable items can be restricted to OSD Position and Language by setting the lock out facility. PROCEDURE 1. To make the lock out facility available 1) Turn ON the Power Switch while pressing the Menu Button, and then turn OFF the Power Switch. 2) Turn ON the Power Switch again while pressing the + Button, and then turn OFF the Power Switch.
  • Page 10 3) Double-click “Universal serial bus controller” as shown in Fig 1 on next page. 4) Confirm that “Generic USB Hub” or “Iiyama USB Hub” appears as shown in Fig 2. 5) Disconnect the USB Cable from the USB compliant computer.
  • Page 11 Fig. 1 Double-click here Fig. 2 Fig. 3 “Generic USB Hub” or “Iiyama USB Hub” - 5 -...

  • Page 12: Circuit Description

    3. CIRCUIT DESCRIPTION 3-1. POWER circuit The Power source of AC90-264V is converted to DC12V, DC 5V (USB) and DC14V by the POWER-UNIT. Converted DC12V is supplied to PWB-MAIN, inverter and the backlight as a power source. DC12V and DC14V supplied to PWB-MAIN is regulated to power source of each block by the regulator IC.
  • Page 13 3-2. SYNC PROCESSING circuit H/V Sync signal from the PWB-A/V is passed to the SYNC PROCESSING IC (IC204) via Schmitt input BUFFER (IC202). Sync On Green is separated into VIDEO signal and Sync signal by IC203. The output of IC203 is passed via the BUFFER (IC202) to IC204.
  • Page 14 3-4. FREQUENCY CONVERSION circuit The input signals from DC-AC CONVERTER (IC401) to TFT CONTROLLER (IC501) are memorized in the MEMORY (IC502 and IC503). The input signals are converted to SXGA at 60Hz when read out from the MEMORY. The same frequency as the input signal R,G,B, DATA MEMORY R,G,B, DATA...
  • Page 15 3-6. BACKLIGHT and INVERTER (BRIGHTNESS) CONTROL circuit The inverter converts DC12V to the power source of AC650Vrms for lighting the backlight by the DC-AC CONVERTER, and turns on the cold cathode tube. Signals controlled by the MICROPROCESSOR (IC701) are as follows: BKLTC signal: Turn ON and OFF the inverter output and applied for picture mute.

  • Page 16: Service Parts List

    4. SERVICE PARTS LIST WARNING ! The components identified by “ ! ” in this manual are critical for safety. Replace only with part number specified. - Page- <CONTENTS> Abbreviations and Marks .................. FAMILY-TREE ....................ASSY-PACKING ....................ASSY-LCD ....................... ASSY-PWB-MAIN ................... 14-21 ASSY-PWB-MIX2 .....................
  • Page 17 ELECTRICAL PARTS LIST š Abbreviations in PART section › Abbreviation Meaning Resistor-Carbon R-MB Resistor-Metal Capacitor-Ceramic Capacitor-Electrolytic C-E-NP Capacitor-Electrolytic Non-Polar C-MF Capacitor-Stacked Metallized Plastic Film Diode Zener Diode Transistor Variable Resistor Switch š Marks in DESCRIPTION section › <Resistor> <Capacitor> Mark Tolerance Mark Tolerance...

  • Page 18: Exploded View

    5. EXPLODED VIEW Note: The numbers in this exploded view are the same as the reference numbers in the Chapter 4. ASSY-LCD ×2 L=100mm - 26 -...
  • Page 19 15-20 L=30mm ×2 USB Hub Windows 95/98/2000Plug&Play JAPAN GOLF TOUR 10-20 FRONT L=600mm L=600mm - 27 -...
  • Page 20 Note: Except where indicate otherwise, all screw torcue is 8±1kgf-cm in ASSY-LCD. ASSY-1 ×2 L=15 INVERTER-CARD FRAME-MAIN UL-TAPE ×5 L=50 ×4 ×4 ×3 50±5 - 28 -...
  • Page 21 ASSY-2 ×4 torque 4±0.5kgf-cm to INVERTER to INVERTER BUTTON-PUSH CHIP-LED - 29 -...
  • Page 22 ASSY-3 ×2 ×2 ×2 ×2 ×2 ×2 ×2 ×2 from LCD module from LCD module - 30 -...
  • Page 23 ASSY-4 ×4 CN101 ×3 ×2 PWB-MAIN ×2 ×2 ×3 PWB-CONTROL ×2 ASSY-5 PWB-AUDIO ×2 PWB-JACK PWB-AC ×2 PWB-JACK - 31 -...
  • Page 24 ASSY-6 PWB-MAIN CLAMPER LEAD PWB-JACK C-CN-N,J CN101-J PWB-AUDIO CN101-J PWB-AC P-CN1 POWER-UNIT CN101-J,S CN101 PWB-CONT ASSY-7 ×4 ×6 ×4 ×2 - 32 -...
  • Page 25 ASSY-8 ×2 ×4 ASSY-STAND ×4 torque 11-13kgf-cm - 33 -...
  • Page 26 Note: Except where indicate otherwise, all screw torcue is 3-5kgf-cm in ASSY-PWB-MAIN. 1+# ASSY-PWB-MAIN - 34 -...
  • Page 27 AC-INLET IC301 AA AB S911 - 35 -...
  • Page 28 Note: Except where indicate otherwise, all screw ASSY-1-A torcue is 6-8kgf-cm in ASSY-STAND. ×3 torque 11-13kgf-cm PWB-USB ×3 60mm PWB-USB - 36 -...
  • Page 29 ASSY-1-B Bule:+ / Yellow:- Red:+ / Black:- ×3 ×2 ×2 SANYO,MINEBEA MATSUSHITA - 37 -...
  • Page 30 ASSY-2 ×4 torque 11-13kgf-cm ×2 ×6 torque 11-13kgf-cm UL-TUBE ×2 ×4 torque 11-13kgf-cm - 38 -...

  • Page 31: Diagrams

    6. DIAGRAMS BACK-LIGHT VIDEO / SYNC CONTROL CONTROL LCD-MODULE PWB-MAIN +12V INVERTER +12V VIDEO / SYNC +12V MENU MINI PWB-JACK VOLUME JACK – MINI D-SUB PWB-CONT JACK MINI 15PIN POWER-UNIT VIDEO IN AUDIO IN AUDIO / CONTROL AUDIO +12V PWB-AUDIO POWER SPEAKER LEFT...