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Service Guide OL800 / OL820
Chapter 0 About This Manual

OL800 // OL820

LED Page Printers

Adobe Acrobat printable reference copy of the OKIDATA Service Training Manual. 09/17/97
Note: This Adobe Acrobat version of the Okidata Service Training Manual was built with the pictures rendered at 300 dpi, which is ideal for printing, but does not view on most displays well.

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

Table of Contents

Page

Service Guide OL800 / OL820
0 About This Manual Front Cover Copyright Manual Part Number and Revision 1 Product Specifications 1.1 Overview 1.2 Print Specifications 1.3 Physical Specifications 1.4 Power Requirements 1.5 Paper Specifications 1.6 Environmental Conditions 1.7 Agency Approvals 1.8 Options ....1.8.01 RAM Expansion Board ....1.8.02 RAM Expansion Chip Set ....1.8.03 Font ROM Cards ....1.8.04 Paper Trays ....1.8.05 Multiport Interface Boards ....1.8.06 Second Paper Feed Mechanism ....1.8.07 OkiXpress 1.9 Consumables 1.10 Reliability Data 2 Principles of Operation 2.1 Printer Overview 2.2 Main Control Unit ....2.2.01 Main Control Board (CTLZ) ....2.2.02 Program Cartridge Board (PRGZ) ....2.2.03 Font Card Board (CMBZ) ....2.2.04 Program Cartridge Connection Board (LNKZ) ....2.2.05 Extended RAM Board (MEMZ) (Option) ....2.2.06 Multi-Port Centronics Parallel Interface Board (CMIZ) (Option) ....2.2.07 Multi-port RS232-C Serial Interface Board (RMIZ) (Option) ....2.2.08 Font Card (Option) ....2.2.09 OL820 Board (OkiXpress Upgrade) 2.3 Printer Control Unit ....2.3.02 Engine Board (LLAB-2) ....2.3.03 Power Supply Unit ....2.3.04 Fuser Unit ....2.3.05 Main Motor (Drum Motor) ....2.3.06 LED Head 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

Table of Contents ....2.3.07 Resist Motor ....2.3.08 DC Fan ....2.3.09 Operation Panel ....2.3.10 Second Paper Tray Mechanism (Option) 2.4 Mechanical Operation Description ....2.4.03 Process Descriptions 2.5 Sensors And Switches ....2.5.02 Sensor Functions 3 Maintenance & Disassembly 3.1 Maintenance ....3.1.02 Maintenance Tools ....3.1.03 Maintenance Precautions 3.2 Disassembly/Assembly Procedures ....3.2.01 Upper Cover ....3.2.02 LED Head ....3.2.03 Interface Board ....3.2.04 RAM Board (Option) ....3.2.05 Main Controller Board ....3.2.06 Engine Controller Circuit Board (LLAB) ....3.2.07 Main Motor ....3.2.08 DC Fan Assembly ....3.2.09 Idle Gears "A" and "B", and the Reduction Gear ....3.2.10 Power Supply Unit ....3.2.11 Upper Unit ....3.2.12 Fusing Unit ....3.2.13 Backup Roller ....3.2.14 Transfer Charger Assembly ....3.2.15 Resist Roller Assembly ....3.2.16 Idle Gear C ....3.2.17 Paper Supply Unit ....3.2.18 Resist Motor ....3.2.19 Engine Connection Board ....3.2.20 Hopping Roller ....3.2.21 Separator ....3.2.22 Ozone Filter 3.3 Adjustments And Service Checks 3.3.02 Actual Page Count ....3.3.03 Modified Page Count ....3.3.04 Vertical Print Start Position Adjustment ....3.3.05 Setting the LED Head Drive Time ....3.3.06 Voltage Adjustment (+5 vdc) ....3.3.07 Darkness Control 3.4 Cleaning 4 Failure & Repair Analysis

Page 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79

Table of Contents 4.1 Overview 4.2 Troubleshooting Updates 4.3 Reporting Problems 4.4 Troubleshooting Tips 4.5 Fault Alarms ....4.5.02 Error Messages Table ....4.5.03 Output Samples 4.6 Repair Analysis Procedures ....4.6.02 RAP Index ........RAP 01 Printer Does Not Initialize ........RAP 2a Paper Feed Jam 1 Alarm ........RAP 2b Paper Feed Jam 2 Alarm ........RAP 03 Paper Jam Alarm ........RAP 04 Size Tray Error Alarm ........RAP 05 Engine Error Fusing Problem Alarm ........RAP 06 Error Engine Alarm ........RAP 07 Error Operator Panel Interface Timeout ........RAP 08 Loop Test Failure (RS232C) ........RAP 09 Error Resident RAM Check ........RAP 10 Error Option RAM Check ........RAP 11 No Operator Panel Display ........RAP 12 Light or Blurred Output ........RAP 13 Dark Background ........RAP 14 Blank Output ........RAP 15 Vertical Black Stripes ........RAP 16 Repeating Marks ........RAP 17 Blank Spots ........RAP 18 Vertical White Stripes ........RAP 19 Black Output ........RAP 20 Poor Fusing 4.7 Self-Tests A Reference Charts A.1 Overview A.2 Index to Charts ....A.2.01 Main Controller Board (CTLZ) ....A.2.02 Engine Controller Board (LLAB-2) ....A.2.03 Operator Panel Board (LLJA) ....A.2.04 Power Connection Board (LLID) ....A.2.05 Engine Connection Board (LLCC) ....A.2.06 Font Card Board (CMBZ) ....A.2.07 Program Cartridge Board (PRGZ) ....A.2.08 Power Supply Unit ....A.2.09 Connection Board (LLIC) ....A.2.10 Program Cartridge Connection Board (LNKZ)

Page 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122

Table of Contents ....A.2.11 Second Tray Driver Board (LLFC) (Option) ....A.2.12 RAM Board (MEMZ) (Option) ....A.2.13 Multi-Port Centronics Interface Board (CMIZ - Option) ....A.2.14 Multi-Port RS-232C Interface Board (RMIZ) (Option) ....A.2.15 OL820 Controller Board (OkiXpress) B Illustrated Parts Listing B.1 Illustrated Parts Listing ....B.1.02 Definitions of Terms ....B.1.03 Parts Ordering Information B.2 CHARTS ....B.2.01 Illustrated Parts Listing (1 of 7) ....B.2.02 llustrated Parts Listing (2 of 7) ....B.2.03 Illustrated Parts Listing (3 of 7) ....B.2.04 Illustrated Parts Listing (4 of 7) ....B.2.05 Illustrated Parts Listing (5 of 7) ....B.2.06 Illustrated Parts Listing (6 of 7) ....B.2.07 Illustrated Parts Listing (7 of 7)

Page 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138

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Service Guide OL800 / OL820
Chapter 0 About This Manual

This document may not be reproduced without written permission of the Okidata® Technical Training Group. Every effort has been made to ensure the accuracy of the information contained in this training course. Okidata is not responsible for errors beyond its control. Please address any comments on this publication to: Technical Training Group Okidata 532 Fellowship Road Mount Laurel, NJ 08054-3499 Fax Number: (609) 235-2600, ext. 7034 Okilink Login Name: Technical Training Okidata is a registered trademark of Oki Electric Industry Company, Ltd.; marques deposee de Oki Electric Industry Company, Ltd.; marca registrada, Oki Electric Industry Company, Ltd. Microline is a registered trademark of Oki Electric Industry Company, Ltd. OkiXpress is a registered trademark of Oki Electric Industry Company, Ltd. Centronics is a registered trademark of Centronics Inc. Diablo is a registered trademark of Xerox Corporation Epson is a registered trademark of Seiko Epson Corporation IBM is a registered trademark of International Business Machines, Inc. LaserJet and LaserJet+ are registered trademarks of Hewlett Packard Corporation Proprinter is a registered trademark of International Business Machines, Inc. Note: The OL800/820 Service Training course is part of the OL-Series Training Course and can not be purchased separately.

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Service Guide OL800 / OL820
Chapter 0 About This Manual

Note: The OL800/820 Service Training course is part of the OL-Series Training Course and can not be purchased separately. © 1994 by Okidata All rights reserved. First Edition, March 1992 Second Edition May, 1994 Written and produced by the Okidata Technical Training Group THE OL400/800/820/830/840 VIDEO TRAINING KIT covers the following products: o OL400 o OL800 o OL820 o OL830 o OL840 The following items are included in the kit: o OL400 Service Handbook o OL800/820 Service Handbook o OL830 Service Handbook o OL840 Service Handbook o Service Training Video o OL400/800/820 User's Documentation o OL830 User's Documentation o OL840 User's Documentation Price: $95.00 ($124.00 Canadian) P/N 58226902

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.1

OVERVIEW

1.1.01 General Information The OL800 is a desktop, page printer, using a stationary LED head and dry electrophotography as its exposure and development methods. The printer has a resolution of 300 x 300 dots per inch and a continuous print speed of 8 letter-sized sheets per minute. A 512Kbyte page memory is standard on the OL800; this can be expanded in 1 Mbyte increments to 4.5 Mbyte with an optional RAM printed circuit board and memory chips. The OL800 has three emulations. The HP Laserjet Series II emulation has 36 resident fonts. The Diablo 630 emulation has 18 resident fonts and the IBM Proprinter XL emulation includes twenty-six fonts. Two optional font cards can be installed with the Diablo and HP emulations. Six cards are available at this time. The OL800 also accepts downloadable fonts. Both a Centronics parallel interface and an RS-232C serial interface are standard. Two consumables are used in the printer. The toner cartridge kit contains a toner cartridge, a fuser cleaner pad, and an LED lens cleaner. The other consumable, the image drum cartridge kit, includes an image drum cartridge and an ozone filter. A letter-size paper tray is included with the printer, and legal, envelope, executive, and A4 trays are also available. Paper feeding can be done automatically or manually. The printer will print on a variety of paper types, labels, envelopes, and transparencies. The OL820 includes all the features of the OL800, plus thirteen resident Bitstream typefaces. An OL800 may be upgraded to an OL820 with the addition of OkiXpress. This feature provides instant scaling of typefaces from 4 points to 240 points by using a proprietary font scaling chip and Okidata provided software drivers.

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.2

SPECIFICATIONS

1.2.01 Print Specifications Development method: Dry electrophotography Exposure method: Stationary LED head 1.2.02 Print Speed First print: 28 seconds maximum (letter size) Continuous print: 8 sheets/minute (letter size) Warm-up time: 40 seconds maximum [at room temperature 77oF (25oC) and rated voltage (120 VAC)] 1.2.03 Symbol Sets Thirty-nine symbol sets are available through the OL800. 1.2.04 Available Fonts The resident fonts in the OL800 and 820 are: HP Emulation: 36 resident fonts Diablo 630 Emulation: 18 resident fonts IBM Proprinter XL Emulation: 26 resident fonts The resident fonts specific to the OL820 are: 13 resident Bitstream scalable typefaces in the HP Emulation (using an OL820 software driver) 1.2.05 Paper Feed Method Automatic feed Manual Feed 1.2.06 Paper Delivery Method Face down/face up 1.2.07 Print Resolution 300 x 300 dots/inch Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.3

PHYSICAL SPECIFICATIONS

1.3.01 Outside Dimensions Width: 17.72" Height:9.49" Length: 17.72" 1.3.02 Printer Weight 37 lbs. 1.3.03 LED Array Number of LED Elements - 2560

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.4

POWER REQUIREMENTS

1.4.01 Input Power 120 VAC +5.5%, -15% 220/240 VAC +/-10% 1.4.02 Power Consumption Approximately 800 W maximum during operation

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.5

PAPER SPECIFICATIONS

1.5.01 Paper Types Letter Size: 8.5" x 11" Feed: Automatic or Manual Weight: Minimum 16 lbs Maximum 24 lbs Recommended 20 lbs Legal Size: 8.5" x 14" Feed: Automatic (with optional paper tray) or Manual Weight: Minimum 16 lbs Maximum 24 lbs Recommended 20 lbs Executive Size:7.25" x 10.5" Feed: Automatic (with optional paper tray) or Manual Weight: Minimum 16 lbs Maximum 24 lbs Recommended 20 lbs A4 Size:8.27" x 11.69" Feed: Automatic (with optional paper tray) or Manual Weight: Minimum 16 lbs Maximum 24 lbs Recommended 20 lbs Envelope Size:Minimum 3.5" x 7.5" Maximum 7.2" x 10.1" Feed: Automatic (with optional paper tray) or Manual Weight: Minimum 16 lbs Maximum 24 lbs Recommended 20 lbs Labels - Manual feed / Face up delivery only Use labels designed specifically for laser printers. Transparencies - Manual feed / Face up delivery only Must be able to withstand the heat of the fusing process.

CAUTION: Envelopes, labels, and transparencies should only be fed from the top paper tray. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.6

ENVIRONMENTAL CONDITIONS

1.6.01 Ambient Temperature and Relative Humidity Operation 50° to 89° F (10° to 32° C) 20 to 80% Relative Humidity Storage 14° to 122° F (10° to 50° C) 1.6.02 Printer Noise Level During operation: 50 dB maximum At standby: 43 dB maximum Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.7

AGENCY APPROVALS FCC Class B UL 478 Ver.5 CSA 22.2 220

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8

OPTIONS Ram Expansion Board ........................ ( Ram Expansion Chip Set .................... ( Font ROM Cards ................................ ( Paper Trays ....................................... ( Multiport Interface Boards .................... ( Second paper Feed Mechanism ............( OkiXpress ........................................... ( ) ) ) ) ) ) )

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.01 RAM Expansion Board 1 megabyte (expands printer memory to 1.5 megabytes)

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.02 RAM Expansion Chip Set 1 megabyte memory expansion chip set used in conjunction with the RAM Expansion Board option (expands printer memory up to 4.5 megabytes in 1 megabyte increments).

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.03 Font ROM Cards Letter Gothic Prestige Elite Tax Barcodes Plus MicroDocs OKIPRO

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.04 Paper Trays Letter size Legal size Envelope Executive A4

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.05 Multiport Interface Boards RS-232C Serial Provides two additional RS-232C serial connectors. One or all three interfaces may be selected and each port can be individually configured.

Centronics Parallel Provides two additional Centronics parallel connectors. One or all three interfaces may be selected and each port can be individually configured.

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.06 Second Paper Feed Mechanism Converts printer to allow paper feeding from two paper trays. The second paper tray must be purchased separately.

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.8.07 OkiXpress A printed circuit board which upgrades an OL800 to an OL820. The proprietary font scaling chip mathematically sizes fonts, allowing instantaneous printing. Scalable fonts are accessible in the HP emulation using an OL820 software driver.

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.9

CONSUMABLES Toner Cartridge Kit (P/N 52104201) (1) Toner Cartridge (1) Fuser Cleaner Pad (1) LED Head Cleaning Pad

I

Image Drum Cartridge (P/N 56106601) (1) Image Drum Cartridge (1) Ozone Filter

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Service Guide OL800 / OL820
Chapter 1 Product Specifications

1.10

RELIABILITY DATA

1.10.01 Printer Mean Page Between Failure (MPBF) Approximately 32,000 pages 1.10.02 Printer Mean Time To Repair (MTTR) Approximately 20 minutes 1.10.03 Estimated Printer Life Approximately 360,000 pages 1.10.04 Estimated Fuser Life Approximately 180,000 pages 1.10.05 Printer Duty Cycle Approximately 5,000 pages per month @ 5% print density

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.1

PRINTER OVERVIEW

2.1.01 General Information This section describes the operation of the printer in the order listed below. Main Control Function Printer Control Function Mechanical Operation Sensors and Switches

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2

MAIN CONTROL UNIT

The main control unit controls the reception of data from the host interface (interface), processes command signals, processes the image signals, controls the printer unit, outputs data, and controls the operation panel. The principal hardware configuration of the main control unit is listed below. Main Control Board Program Cartridge Board Font card board Program Cartridge Connection Board Extended RAM Board (Option) Multi-Parallel Interface Board (Option) Multi-Serial Interface Board (Option) Font Card (Option) OL820 Controller Board (OkiXpress Upgrade)

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.01 Main Control Board (CTLZ) The Main Control Board consists of the Motorola 68000 CPU, font ROM, RAM, and two gate arrays. The Main Control Board is connected to a host system through a Centronics parallel interface or an RS-232C serial interface. Either of the two interface ports can be used when specified by the control panel. The unused interface port outputs a busy signal. The Main Control Board receives print data and string commands from the host system, and generates bit image data. The programs for these procedures are stored in the Program ROM installed on the Program Cartridge Board.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.02

Program Cartridge Board (PRGZ)

Two EPROMS IC3 and IC5 (1Mbit) are mounted on the Program Cartridge Board. The Program Cartridge, which is installed in the control unit, provides programs for the three printers listed below. LaserJet Series II®: Hewlett Packard Diablo 630®: Xerox IBM ProPrinter XL®: IBM The emulation can be selected through the printer menu or via software commands from the host.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.03

Font Card Board (CMBZ)

The connectors for the optional font cards are provided on the Font Card Board. The font data is sent to the Main Control Board (CTLZ) through the Program Cartridge Connection Board (LNKZ).

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.04 Program Cartridge Connection Board (LNKZ) This connection board is housed in the cabinet and relays data between the program cartridge (PRGZ Board) and CPU bus. The connection board also contains the bus buffer to enable the optional font card data to be loaded on the Main Control Board (CTLZ) via the data bus.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.05 Extended RAM Board (MEMZ) (Option) The extended RAM Board includes 1 Mbyte of RAM , and IC sockets for an additional 3 Mbyte. This 4 Mbyte plus 512 Kbyte on the Main Control Board extends RAM to 4.5 Mbyte. RAM is extended in 1 Mbyte increments. The CPU detects the extended RAM board by sending the MEMEXIST signal. The RAM capacity is identified during the Power-on sequence. Also, RAM capacity is output during Menu Print.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.06 Multi-Port Centronics Parallel Interface Board (CMIZ) (Option) The multi-port parallel interface is equipped with two Centronics parallel port connectors, in addition to the resident parallel port. When the multi-port parallel interface is installed, and enabled through the menu, three parallel ports are put in the on-line state and are polled for data. When data is received from any one port, the port that has received data is locked in the on-line state. When the locked port does not receive data for more than 15 seconds, it automatically enters the polling mode.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.07 Multi-port RS232-C Serial Interface Board (RMIZ) (Option) The multi-port RS232-C Serial interface Board provides two serial ports in addition to the resident serial port. It operates under the same time sharing principals as the Multi-port Centronics Parallel Board. Since a polling sequence is used, the serial multi-port interface will only function in the Ready/Busy (Hardware Handshake) mode.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.08 Font Card (Option) Up to two font cards for additional bit map fonts can be installed. A ROM on the font card provides the optional fonts. If the printer is in the off-line state (the READY lamp is off), the card can be inserted and removed . When the font card is inserted and removed in the on-line state (the READY lamp is on), a CARD REMOVED ON-LINE error message appears on the LCD display.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.2.09 OL820 Board (OkiXpress Upgrade) The heart of this board is the Blue Point font scaling chip, which is a 20K gate array graphics co-processor specially designed for font generation. It generates characters as a bit mapped image in system band buffer RAM from instructions stored in the font ROM's. These instructions tell the font scaling chip to draw lines that form the characters and to fill the space enclosed by the lines with any desired pattern including full black as in normal printing. The OL820 Program ROMs are located at Q52 and Q53. This board also contains the four 1Mbit ROMs are located at Q40 thru Q43.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3 PRINTER CONTROL UNIT 2.3.01 General Information The principal hardware components of the printer control unit are listed below. Engine Board Power Supply Unit Fuser Unit Main Motor LED Head Resist Motor DC Fan Operation Panel Second Paper Tray Mechanism (option)

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.02 Engine Board (LLAB-2) The Engine Board contains an 80C51, or a 83C154 microprocessor (8-bit), an EPROM which stores the Engine Control Program and an EEPROM. When the 83C154 Microprocessor is installed (LLAB-2 Revision 11) the EPROM is not required. The Engine Board (LLAB-2) turns the LED Array diodes ON, which leaves a latent image on the photosensitive drum. The Engine Board also controls the paper feed, paper transport, and electrophotographic processing actions so that the latent image is printed by fusing toner on the paper. The 1-Kbit Electrically Erasable PROM (EEPROM) is loaded with the data listed below. Total number of sheets printed after installation Modified page count Total number of sheets printed with the current drum Total number of sheets printed with the current fuser Setting of time required from the completion of printing to Quiet Mode Feed time needed to feed the paper to a printable position Vertical Registration (Top margin) LED Head Drive Time Note: The EEPROM preserves the data while the supply voltage is off. The counters stored in the EEPROM can be accessed by using SW1 on the Engine Board to set the printer in the Maintenance Mode. (See Section 3 of the Service Handbook) The count of the total number of sheets printed after installation cannot be reset. The count of the total number of sheets printed with the drum currently in use should be taken as a rough measure of the useful life of the drum; it is reset to zero when the drum is replaced by holding down the RESET button and applying power to the printer.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.03

Power Supply Unit

The power supply unit generates the voltages listed below from the AC input voltage. Voltage +5vdc +12vdc -12vdc +38vdc +5Kvdc -6Kvdc -600vdc -550,-400vdc High Voltage Drive The high-voltage circuit provides a charge voltage (about -6Kvdc), a transfer charge voltage (about +5 Kvdc), a grid voltage (about -600 vdc), and developer bias voltages (about -550vdc and -400vdc). Of these voltages, the charge voltage and the transfer charge voltage are generated by a high-voltage power supply. The grid connects to ground via a varistor on the medium-voltage generation circuit. It is kept at about -680 vdc during charging. Purpose Logic Levels,, LED Head Drive Voltage Interface Line Voltage Interface Line Voltage Motor/Fan Drive Voltage: High Voltage Source Transfer Charge Voltage Drum Charge Voltage Charge Grid Voltage Developer Bias Voltages

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.04

Fuser Unit

The fuser unit heater is controlled by a thermistor, a comparator, an LSI, and the CPU to keep the heat roller surface temperature within a predetermined range (about 150 degrees Celsius). A thermostat within the fuser unit prevents abnormal temperature rises in the fuser unit if the thermistor fails. Note: The CPU checks for an open circuit in the thermistor at power-on , setting a fuser alarm if this error is detected. The CPU also sets a fuser alarm if the proper temperature is not attained within a specified period of time after power-on. Upon detecting a fuser alarm, the CPU will halt (after printing the current page).

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Chapter 2 Principles of Operation

2.3.05 Main Motor (Drum Motor) The main motor is driven by the motor drivers, T21,T22,T23 and T24. It is a two-phase motor, driven by the DM-PH 1 and 2 signals.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.06

LED Head

Data on the 2,560 LEDs in the LED head is set in the shift register by the HD CLK signal. The data is loaded in the latch circuit by the HD LD signal. The on/off states of the LEDs are controlled by the signals STB1- STB4; 640 bits are turned on or off at a time.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.07 Resist Motor The resist motor is driven clockwise (Hopping), then counterclockwise (Paper Feed) by the motor drive IC (LB1731). It is four-phase motor, driven according to the RM-H1, RM-H2, and RM ON-P signals generated from the LSI.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.08 DC Fan The fan is controlled by the FAN ON-P signal from the LSI (MSM73H019). In order for the fan to operate, the signal FAN SENSE-N must be active. Note: The fuser and the fan are not enabled when the cover is open . If the fan fails to run, the fuser will turn off and FAN ALARM is set. Printing is disabled.

In accordance with the TIME TO QUIET setting of the Level 2 Menu, the Fuser will maintain the proper fusing temperature for 1 or 8 minutes after the last page has been printed. If printing is not requested within the selected time frame, the fuser will turn OFF and the fan speed will be reduced 50%. Selecting DISABLE allows the FUSER to maintain the proper fusing temperature continuously.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.09 Operation Panel The components listed below make up the operation panel. 4-bit MPU (LC6543C) LCD control driver (MSM6222B or HD44780) LCD display (16 characters per line) Operation panel sheet LEDs (for online mode indication) Operation buttons The operation panel is connected to the Main Control Board via the Engine Connection Board, the Engine Controller Board and the Program Cartridge Controller Board. The operation panel is controlled by the Main Control Board with its operation panel interface signal. The LCD control driver (MSM622B or HD44780) converts 4-bit character codes received from the MPU into 8-bit character codes and retrieves the character pattern data (font) associated with the 8-bit character codes from the internal character generator for display on the LCD. Operation Panel Interface The operation panel is controlled by the operation panel interface located on the Main Controller Board via the Engine Board. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.3.10 Second Paper Tray Mechanism (Option) The Second Paper Tray Mechanism is controlled by the Second Tray Driver Board (LLFC). This board is attached to the left side of the optional second paper tray mechanism. The resist motor and paper tray detection sensors are mounted on this board.

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.4

MECHANICAL OPERATION DESCRIPTION

2.4.01 Basic Principles of Electrophotography A photoconductive drum is charged by a high voltage from the power supply. The printer turns on the LED head according to the data received from the controller. The charged drum is exposed to this light, forming a latent image on the drum surface. This latent image is developed by toner, with the resultant toner image being transferred to paper and fused for printing. The electrophotographic technology used in this printer is similar to that embodied in general copying machines. The technology is made up of the following processes. Charging The surface of the photoconductive drum is uniformly charged. Exposure The charged photoconductive drum is exposed to light, forming a latent image associated with the print image on the drum. Developing Charged toner is attracted to the latent image by static electricity, making the image visible. Transfer The toner is attracted to the paper by a static charge. Cleaning Residual toner is removed from the image drum surface. Fusing The toner image is fused to the paper using heat and pressure. Toner Recycling Toner that is collected during cleaning is returned to the developer.

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Chapter 2 Principles of Operation

2.4.03 Process Descriptions Hopping and Feeding Hopping and feeding are accomplished by the resist motor, hopping roller, and resist rollers. Turning the resist motor in the clockwise direction drives the hopping roller. Turning the resist motor in the counter-clockwise direction drives the resist rollers. Hopping Hopping is loading paper from the tray. The resist motor turns the hopping roller to advance the paper until the inlet sensor turns on. After the paper has turned on the inlet sensor, the hopping roller advances the paper until it contacts the resist roller. The resist roller corrects paper skew. Feeding Feeding is transporting the paper through the printer.

At the end of hopping, the resist motor reverses and the resist rollers transport the paper through the printer. Charging -6 Kvdc is applied to the charge wire. This causes negative ions to be generated in the vicinity of the charge wire (corona discharge). The negative ions are discharged to the grid plate and the image drum surface. Since the drum surface is not conductive (in the dark), the negative charge (approximately -700 vdc) remains on the drum. To ensure that the drum surface is not charged with more than -700 vdc, a varistor is connected between the grid and ground. If the grid voltage exceeds -700 vdc, the varistor shunts this excess voltage to ground.

Exposure Light emitted from the LED head is radiated to the image drum surface which is charged with negative ions. The areas of the drum that light is directed to become conductive. This allows the surface potential in these areas to drop from -700 vdc to approximately -100 vdc, thereby forming a latent image associated with the image signals.

Developing The toner supply roller and the development roller are supplied with bias voltages required during the developing process. -550 vdc is supplied to the toner supply roller, -400 vdc to the development roller. The toner supply roller is constructed of a porous material which absorbs toner. Since the development roller charge is more positive than the toner supply roller charge, toner is attracted from the toner supply roller to the development roller.

The toner attracted to the development roller is scraped off by the doctor blade, forming a thin coat of toner on the development roller surface.

Since the areas of the drum exposed to light (-100vdc) are charged more positive than the toner

(-400 vdc), the toner is attracted to the exposed areas of the Image drum surface, making the latent image visible. Transfer As paper passes by the image drum surface, a positive charge (+5Kvdc), is applied to the charge wire causing the paper to be charged positively through corona discharge. Since the paper is charged more positive than the toner (-100 vdc), the toner is attracted to the paper.

Cleaning Upon completion of transfer, residual toner on the image drum is scraped off by the cleaning blade. The residual toner is returned from the toner recovery unit to the developer unit for reuse. Fusing The toner image is fused on the paper by passing it between the heated roller and the back-up roller. The heated roller is teflon coated and contains a 600 watt quartz lamp. The back-up roller and springs provides a pressure of 3 kg. A thermistor regulates the heated roller temperature at a predetermined temperature (about 150° C). A thermostat cuts off voltage supply to the heater in the event of abnormal temperature rise. Paper Ejection Paper is ejected from the fuser unit by the back-up roller. If the face-up stacker is closed, paper is routed to the top of the printer for face-down delivery. Toner Recycling Toner in the recovery tank is moved to the toner cartridge for re-use.

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Chapter 2 Principles of Operation

2.5

SENSORS AND SWITCHES

2.5.01 Sensors and Switches Inlet Sensor (Photosensor)

Outlet Sensor (Photosensor)

Paper Tray Identification Switches

Paper End Sensor (Photosensor)

Cover Open Switch

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Service Guide OL800 / OL820
Chapter 2 Principles of Operation

2.5.02 Sensor Functions At Power-On The inlet and outlet sensors are checked for their on and off states at power on. Inlet sensor ON: PAPER FEED JAM ERROR (Paper supply jam) Outlet sensor ON: OUTLET JAM ERROR (Paper eject jam) The thermistor sensor circuit detects if the temperature of the fusing unit reaches the normal temperature within the specified time. When it does not reach the normal temperature within the specified time, the thermistor sensor turns OFF the heater and generates an alarm. During Hopping Whenever the inlet sensor fails to detect paper within a predetermined period of time after a feed command has been issued to the paper supply system (tray), the failure is counted. The hopping operation is attempted three times. If the paper fails to feed properly, a PAPER FEED JAM ERROR occurs. During Feeding If the leading part of the paper does not reach the outlet sensor within a predetermined period of time after the start of feeding by the resist motor, a PAPER JAM ERROR occurs. Detection of Form Length Errors by the Inlet Sensor Form length detection is not enabled for manually fed paper or envelopes. Any form length other than those specified in Section 1 of this Service Handbook will generate a FORM LENGTH ERROR. To detect the form length, the processor measures the time interval between the activation of the inlet sensor and the deactivation of the inlet sensor (after the start of the resist motor in the forward direction. Detection of Outlet Jams by the Outlet Sensor Since paper is fed through the printer at a fixed speed, the outlet sensor must remain on for a predetermined length of time. If the sensor remains on in excess of this time, the controller assumes that an exit jam has occurred and an alarm is generated. Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Chapter 3 Maintenance & Disassembly

3.1

MAINTENANCE

3.1.01 General Information This section lists the parts replacement, adjustment, cleaning, and lubrication procedures. Disassembly should not be performed unless absolutely necessary. NEVER perform disassembly on a malfunctioning unit until you have followed the failure analysis procedures in Section Four of this Service Handbook ( ). Follow the procedures listed in Adjustments and Service Settings ( ). Adjustments may be required when either consumables or parts are replaced. Failure to perform these procedures could result in unnecessary service calls. Cleaning procedures must be performed correctly if high print quality is to be achieved.

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Chapter 3 Maintenance & Disassembly

3.1.02

Maintenance Tools

The following tools are required to service the unit. #2 Phillips Screwdriver (with magnetic tip) Straight-slot Screwdriver Needle Nose Pliers (4 Inch) Digital Multimeter Shop Vacuum (with filter for toner) Cloth (soft and lint-free) All-purpose Cleaner Grease (Dow Corning BR2 or equivalent)

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.1.03 Maintenance Precautions Do NOT disassemble the unit if it is operating normally. Before starting disassembly and assembly, always power OFF the unit and detach the power cord. Detach the interface cable, if installed. Do not remove parts unnecessarily. Try to keep disassembly to a minimum. Use the recommended maintenance tools. When disassembling, follow the listed sequence. Failure to follow the correct sequence may result in damaged parts. Screws, collars and other small parts are easily lost. Temporarily attach these parts to their original positions. When handling circuit boards use extreme care. Integrated circuits (microprocessors, ROM, and RAM) can be destroyed by static electricity. Do not place printed circuit boards directly on conductive surfaces. Follow the recommended procedures when replacing assemblies and units. Clear the drum counter when a new drum cartridge is installed. 1. Power OFF the unit. 2. Press and hold RESET while powering ON the unit. 3. The drum counter will reset. Clear the fuser counter when a new fusing unit is installed. Refer to Section 3.3( in this Service Handbook (doclinks). ), Adjustments

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Chapter 3 Maintenance & Disassembly

3.2

DISASSEMBLY/ASSEMBLY PROCEDURES

General Information This section contains the printer disassembly procedures. Only the removal procedures are explained. Reverse the procedure for the installation. This Service Handbook lists the disassembly procedures for major components of the unit. Okidata does NOT recommend disassembling a unit which is operating normally. If you decide to perform disassembly during this training, Okidata recommends that you perform only the disassembly procedures for RSPL items. All other procedures are provided to assist you in identifying parts. It is not likely that you will perform these procedures while servicing the product. Read all notes, cautions, and warnings. They contain important information regarding assembly/disassembly.

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.2.01 Upper Cover Turn the power switch OFF and unplug the AC power cord from the outlet and the printer power receptacle at the rear of the printer. Remove the paper tray (1), interface cable (2), and font card (3) (if installed). Lift the operator panel assembly (4) at its bottom and detach it. Pull on the locking collar and then detach the connecting cable (5) from connector J1 (6) of the operator panel PCB (7). Note: Please note that when assembling the operator panel board, you must install the connecting cable with the blue strip to the left. Press the "OPEN" button (8) and raise the stacker cover (9). Remove the two screws (10) and lift the front side of the upper cover (11). As you lift, you will disengage the upper cover from the lower cover at the back of the printer. Note: Installation Open the stacker cover. Align the square slots of the upper cover with the claws of the lower cover. The claws are located on the back of the lower cover, at the left and right sides. Lower the upper cover into position. If the cover is not installed properly, paper jams will result.

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Chapter 3 Maintenance & Disassembly

3.2.02 LED Head Perform this procedure: 3.2.01 ( )

Push the two blue lock levers (1) toward the rear of the printer and open the LED holder (2). Lift and remove the image drum cartridge (3). To protect the image drum cartridge, please place it back in the styrofoam shipping package.

LED Head Replacement After replacing the LED head, set the LED head drive time as described in Section 3.3 of this Service Handbook ().

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.2.03 Interface Board This procedure may be used to remove both the parallel and serial interface boards. Perform this procedure: 3.2.01 ( ) Remove the three shield cover mounting screws (1) and detach the shield cover (2) by sliding it forward and lifting it. Remove the interface board mounting screw (3) and the post (4). Lift the interface board (5) to disconnect it from the control board (6) for removal.

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.2.04 RAM Board (Option) Perform this procedures: 3.2.01 ( )

Remove the three shield cover mounting screws (1) and detach the shield cover (2) by sliding it forward and lifting it. Press the hook of the locking circuit board support (3) to unlock the RAM board (4). Lift the RAM board to disconnect it from the main controller board (5) for removal.

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Chapter 3 Maintenance & Disassembly

3.2.05 Main Controller Board Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) Remove the three controller board mounting screws (1). Lift the main controller board (2) to disconnect it from the engine control circuit board (3) and remove the main controller board.

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.2.06 Engine Controller Circuit Board (LLAB) Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( )

Disconnect the cables (1) from connectors J1, J2, and J5. Open the LED holder to allow access to the engine board mounting screw (2) and remove the mounting screw. Close the LED holder and raise the upper unit. Remove the two remaining mounting screws (3). CAUTION: Be careful not to lose the plastic spacer (4) located between the shield frame and the engine controller board. When installing the engine controller board, be sure that the spacer is in place or the engine controller board will short against the shield frame. Lift the engine controller board (5) to disconnect it from the interconnect board (6). On the engine controller board, press the pawls (7) to unlock and remove the print board cover (8). Note: Replacement When replacing an engine controller board, remove the EEPROM IC2 (9) and the Program PROM Q1 (10) from the old board and mount them on the new board. With LLAB Revision 11, Q1 is not installed because the program is masked in the CPU.

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Chapter 3 Maintenance & Disassembly

3.2.07 Main Motor Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( )

Remove the three mounting screws (1) and detach the shield frame (2). Detach the interconnect board (3). Note: The traces which run the entire length of the board are to the front of the printer when the board is installed. Working from the bottom of the printer, remove the motor cover (4) by releasing the two black claws (5). Remove the two high voltage wires from the motor cover. Shift the motor assembly to the left to remove it from the claws (6) of the lower unit. Working on the motor assembly, remove the two mounting screws (7) to remove the main motor (8) from the motor assembly.

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Chapter 3 Maintenance & Disassembly

3.2.08 DC Fan Assembly Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( )

Detach the shield frame (3.2.07 step 6). Remove the DC fan assembly (1).

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Chapter 3 Maintenance & Disassembly

3.2.09 Idle Gears "A" and "B", and the Reduction Gear Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( ) 3.2.07 ( )

Detach the gears in the following order: idle gear "B" (1), reduction gear (2) and idle gear "A" (3).

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Chapter 3 Maintenance & Disassembly

3.2.10 Power Supply Unit Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( ) 3.2.07 ( )

Disconnect the two high-voltage cables (1). Note: When installing, the cables are keyed for correct placement. The larger connector is to the front of the printer.

Remove the four mounting screws (2). Raise the upper unit. Slide the power supply unit (3) towards the front until it comes off the guide (4) of the lower unit. Lift the power supply unit towards you to detach it from the rear claws (5) for removal.

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Chapter 3 Maintenance & Disassembly

3.2.11 Upper Unit Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( ) 3.2.07 ( ) 3.2.08 ( ) 3.2.10 ( )

Place the face-up stacker assembly, located at the rear of the printer, down. Then, lift the upper unit. Remove the paper eject roller assembly mounting screw (1). Slightly lift the paper eject roller assembly (2) at its left end and slide the left end backward using the right end as a pivot. Remove the assembly. Remove the tension springs (3) using a needle nose pliers. Loosen the two mounting screws (4). Lift the upper unit (5). Slide the upper unit to the right and work it free of the right slot to remove it. CAUTION: Be careful not to drop the fulcrum block (6) and the idle gear (7) when removing the upper unit.

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Chapter 3 Maintenance & Disassembly

3.2.12 Fusing Unit WARNING: Allow the printer to cool before servicing the fusing unit. Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( ) 3.2.07 ( ) 3.2.08 ( ) 3.2.10 ( ) 3.2.11 ( )

Working on the upper unit, remove fuser cleaner pad (1) and the fulcrum block with idle gear (2). Detach the cable (3) from the cable guide (4) of the upper unit. Pass the connector (5) through the slot in the upper unit and work the cable from the upper unit guides. Position the upper unit so its underside is facing you, with the fusing unit (6) at the top. Push the fusing unit against the upper unit until the two lock plates (7) protrude from their slots. Slide the fusing unit to the right until the lock plates disengage from the grooves of the upper unit. Remove the fusing unit, being careful not to lose the springs (8). CAUTION: Installation The four separator claws must move freely within their grooves or paper jams will result.

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Chapter 3 Maintenance & Disassembly

3.2.13 Backup Roller Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.06 ( ) 3.2.07 ( ) 3.2.08 ( ) 3.2.10 ( ) 3.2.11 ( )

Remove the two mounting screws (1). Use a straight slot screwdriver to detach the sheet guide (2). Remove the backup roller (3).

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Chapter 3 Maintenance & Disassembly

3.2.14 Transfer Charger Assembly Turn the power switch OFF and unplug the AC power cord from the outlet. Press the OPEN button and raise the stacker cover. Remove the image drum cartridge (1). (See 3.2.2 ()) Push the lock lever (2) towards the back of the printer to raise the upper unit (3). Firmly push down and back on the sides of the transfer charger assembly (4) until the lower cover claws are disengaged from the square holes on each end of the transfer charger assembly. Lift and remove the transfer charger assembly.

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Chapter 3 Maintenance & Disassembly

3.2.15 Resist Roller Assembly Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) Using a standard screwdriver, release the claws (1) From both sides of the resist roller assembly (2). Note: The left claw can be accessed from the bottom of the printer. Lift the resist roller assembly from the printer.

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Chapter 3 Maintenance & Disassembly

3.2.16 Idle Gear C Perform this procedure: 3.2.01 ( )

Push the lock lever towards the back of the printer to raise the upper unit. Using a needle nose pliers and working from the left side of the printer, push the post (1) to the right. Remove the post. Remove idle gear C (2). Note: top The cutout (3) on the post should be positioned to the left side of the printer and on the when installing.

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Chapter 3 Maintenance & Disassembly

3.2.17 Paper Supply Unit Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( )

Press the lock lever (1) backward and lift the upper unit (2). Disconnect the cable (3) from connector J5 on the engine controller circuit board (4). Remove the two mounting screws (5). Lift the paper supply assembly (6) at its front until the frame of the unit comes off the guide pins, then move the unit towards you for removal.

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Chapter 3 Maintenance & Disassembly

3.2.18 Resist Motor Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.17 ( )

Remove the two mounting screws (1). Detach the resist motor (2).

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Chapter 3 Maintenance & Disassembly

3.2.19 Engine Connection Board Perform these procedures: 3.2.01 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.17 ( )

Remove the two mounting screws. (1) On the paper supply unit, press the pointed end of the nylon latch (2), push out the head (3), and remove the latch. Detach the engine connection board (4).

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Chapter 3 Maintenance & Disassembly

3.2.20 Hopping Roller Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.17 ( )

Remove the two screws (1) and slide the upper plate assembly (2) until the claws (3) are unlocked. Push the hopping roller shaft (4) to the left to unlock it. Remove the hopping gear pin (5). Remove the E-clips (6). Remove the hopping roller pin (7). Slide the hopping roller shaft to the right and remove the hopping roller (8). Note: When installing, always mount the hopping roller shaft above the ground plate, which is on the left side of the printer.

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.2.21 Separator Perform these procedures: 3.2.01 ( ) 3.2.02 ( ) 3.2.03 ( ) 3.2.04 ( ) 3.2.05 ( ) 3.2.17 ( ) 3.2.15 ( ) 3.2.20 ( ) Hold the separator (1) down and remove the escape lever (2) from the pins on the paper supply unit. Be careful not to lose the separator spring (3).

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.2.22 Ozone Filter Note: An ozone filter is provided with the image drum cartridge kit. The filter should be replaced when the image drum cartridge is replaced. Using a screwdriver, insert the blade under the lower portion of the fan cover (1) and twist the screwdriver to remove the fan cover. Remove the ozone filter (2) from the fan cover.

Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.3

ADJUSTMENTS AND SERVICE CHECKS

3.3.01 General Information The first four adjustments (Actual Page Count, Modified Page Count, Vertical Print Start Position and LED Head Drive Time) are performed by changing addresses on the EEPROM located on the Engine Controller printed circuit board. Before performing these adjustments, setup the printer as listed below. Remove the upper cover. Raise the upper unit. Remove the image drum cartridge. Override the cover open interlock switch.

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Service Guide OL800 / OL820
Chapter 3 Maintenance & Disassembly

3.3.02 Actual Page Count General Information The actual page counter counts the number of sheets printed by the printer. Procedure To display the value of the actual page counter, follow this procedure. Power ON the printer while pressing Switch 1 on the Engine Controller Board. The LED (located on the Engine Controller Board) will flash once - then pause (the LED will continuously flash once - then pause) indicating that the printer is in Parameter 1 of the maintenance mode. Press Switch 1 for five seconds. The LED will display the contents of the Parameter1 (Actual Page Counter) register as follows: a. The long flash indicates start of count. b. Short flashes indicate counter contents (most significant digit first). There will be a pause between digits. c. Upon completion of the count,a long flash will indicate start of count. d. This process will loop until you press Switch 1 for five seconds. This will cause the modified page count to be displayed. Example Actual Page Counter = 235 pages Copyright 1997, Okidata, Division of OKI America, Inc. All rig