OKIDATA MICROLINE ML590 User manual

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Page: 1
Service Guide ML590/ML591
Chapter 0 About This Manual
ML590 // ML591
Dot Matrix 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 ML590/ML591
0 About This Manual
Front Cover 1
Copyright 2
Part Number & Manual Revision 3
1 Product Specifications
1.1 General Information 4
1.2 Physical Specifications 5
1.3 Power Requirements 6
1.4 Environmental Conditions 7
1.5 Agency Approvals 8
1.6 Operation Spec's - Print Speed and Character Matrix 9
....1.6.02 Characters Per Line 10
....1.6.03 Character Pitches 11
....1.6.04 Character Sets 12
....1.6.05 Printer Emulations 13
1.6.06 Fonts 14
1.6.07 Front Panel Switches 15
1.6.08 Graphics Resolution 16
1.6.09 Interface 17
....1.6.10 Line Feed Increments 18
....1.6.11 Line Feed Time 19
1.6.12 Menu Mode 20
....1.6.13 Paper Feed Methods 21
....1.6.14 Paper Feed Paths 22
....1.6.15 Paper Loading 23
....1.6.16 Paper Out Detection 24
....1.6.17 Paper Tear Capabilities 25
....1.6.18 Print Method 26
........Printhead Gap Information 27
....1.6.19 Print Modes 28
....1.6.20 Print Speed 29
1.7 Paper Specifications 30
1.8 Memory Specifications 31
1.9 Consumables 32
1.10 Options 33
....1.10.01 Cut Sheet Feeders 34
....1.10.02 Pull Tractor Kit 35
....1.10.03 Color Ribbon Kit 36
....1.10.04 Bottom Push Tractor Kit 37
....1.10.05 Serial Interface 38
....1.10.06 Roll Paper Stand 39
....1.10.07 Bitstream Facelift 2.0 40

Table of Contents Page
....1.10.08 OKISmart Typer Utility 41
....1.10.09 OKISmart Panel Utility 42
1.11 Reliability 43
2 Principles of Operation
2.1 Electrical Operation 44
....2.1.02 Main Control Board 45
........Block Diagram 46
........Program ROM 47
........RAM 48
........Character Generator ROM (CG ROM) 49
........Electrically Erasable Programmable ROM (EEPROM) 50
........LSI 51
....2.1.03 Initialization 52
....2.1.04 Parallel Interface Control 53
....2.1.05 Print Control 54
........LSI/Printhead Interface 55
........Gap Adjust Control 56
........Print Compensation Control 57
....2.1.06 Space and Line Feed (SP/LF) Motor Control 58
........Line Feed Motor Control 59
........Space Motor Control 60
........Encoder Disk 61
....2.1.07 Operation Panel 62
....2.1.08 Alarm Circuit 63
........Head Drive Time 64
........Print Speed 65
........Head Overheat Alarm Processing 66
....2.1.09 Power Supply Circuit 67
2.2 Mechanical Operation 68
....2.2.01 Printhead Mechanism 69
........Interconnect Diagram: Control Board to Printhead 70
........Line Feed Motor Resistance 71
........Space Motor Resistance 72
........Printhead Operation 73
....2.2.02 Spacing Mechanism 74
....2.2.03 Head Gap Mechanism 75
....2.2.04 Ribbon Drive Mechanism 76
........Color Ribbon Shift Mechanism 77
....2.2.05 Line Feed Mechanism 78
........Cut Sheet/Continuous Sheet Switching Mechanism 79
........Cut Sheet Paper Feed Operation 80
........Continuous Paper Feed (Rear Tractor Mechanism) 81
........Continuous Paper Feed (Pull Tractor Mechanism) 82
........Continuous Paper Feed (Bottom Tractor Feed
Mechanism) 83

Table of Contents Page
........Continuous Paper Feed (Push/Pull Tractor Mechanism) 84
....2.2.06 Paper Detection Mechanism 85
....2.2.07 Support Protector Mechanism 86
....2.2.08 Automatic Paper Load 87
....2.2.09 Paper Park 88
3 Maintenance & Disassembly
....3.1.01 General Information 89
....3.1.02 Maintenance Tools 90
....3.1.03 Maintenance Precautions 91
3.2 Disassembly/Assembly Procedures 92
....3.2.01 Preliminary Items 93
....3.2.02 Printhead Assembly 94
....3.2.03 Ribbon Protector 95
....3.2.04 Gear Case Assembly 96
....3.2.05 Pull-up Roller Assembly 97
....3.2.06 Upper Cover, Access Cover, and Sheet Guide
Assemblies 98
....3.2.07 Control Board (AKGI) 99
....3.2.08 Power Supply Assembly 100
....3.2.09 Operator Panel PCB (LEOP) 101
....3.2.10 PC Connector 102
....3.2.11 Space Motor and Roller Guide Assemblies 103
....3.2.12 Carriage Cable 104
....3.2.13 Space Rack 105
....3.2.14 Roller/Holder Backup Assembly 106
....3.2.15 Guide Rail and Adjust Cam 107
....3.2.16 Left Ground Plate 108
....3.2.17 Right Ground Plate 109
....3.2.18 Rear and Cut Sheet Paper Feed Sensor Levers 110
....3.2.19 Platen Assembly 111
....3.2.20 Paper Chute Assembly 112
....3.2.21 Line Feed Motor Assembly 113
....3.2.22 Reset Spring 114
....3.2.23 Idle Gear and Change Lever 115
....3.2.24 Pressure Spring 116
....3.2.25 Carriage Shaft 117
....3.2.26 Leaf Spring 118
....3.2.27 Bottom Paper Sensor Levers 119
....3.2.28 Front Pressure Roller Assembly 120
....3.2.29 Tractor Assembly 121
....3.2.30 Main Frame 122
3.3 Printer Adjustments 123
....3.3.02 Printhead Gap Adjustment 124
....3.3.03 Key Combinations 125

Table of Contents Page
....3.3.04 Menu Operation 126
........Printing the Menu 127
........Reset Menu to Factory Defaults 128
........Limited Operation 129
........Procedure 130
........Menu Settings 131
....3.3.05 Top of Form 132
....3.3.06 Paper Park 133
....3.3.07 Tear Feature 134
....3.3.08 Forms Tear Off 135
3.4 Cleaning 136
....3.4.02 Cleaning Schedule 137
....3.4.03 Cleaning Tools 138
....3.4.04 Areas to be Cleaned 139
3.5 Lubrication 140
3.6 Shipping Instructions 141
4 Failure & Repair Analysis
4.1 Introduction 142
....4.1.02 Printer Serial Number Identification 143
4.2 Reporting Problems 144
4.3 Troubleshooting Updates 145
4.4 Troubleshooting Tips - Preliminary Checks 146
....4.4.02 Problem Categories 147
....4.4.03 Start Here Flowchart 148
....4.4.04 Tips for Preventing Image Problems 149
....4.4.05 Common Problems 150
4.5 Abnormal Output & Output Samples 151
........Left Margin Drifting Problem 152
4.6 Fault Alarms 153
....4.6.02 Alarm/LED Display Troubleshooting Table Index 154
....4.6.03 Alarm/LED Display Troubleshooting Tables 155
4.7 Repair Analysis Procedures (RAPs) 156
....4.7.01 Using the RAPs 157
....4.7.02 RAP Index 158
........RAP 01 No Power Supplied to Printer 159
........RAP 02 No Spacing Operation 160
........RAP 03 Printhead Homing Error 161
........RAP 04 Paper Jam During Paper Loading 162
........RAP 05 Printhead Pins Not Firing 163
........RAP 06 Poor Print Quality 164
........RAP 07 Ribbon Feed Problem 165
........RAP 08 Line Feed Problem 166
........RAP 09 Operation Panel Malfunction 167
........RAP 10 Parallel Interface Problem 168

Table of Contents Page
........RAP 11 Serial Interface Problem 169
4.8 Printer Tests 170
....4.8.02 Rolling ASCII Test 171
....4.8.03 Font Test 172
....4.8.04 Serial Interface Loopback Test 173
........Serial Cable Information 174
........Commonly Used Serial Cable Configurations 175
....4.8.05 Hexadecimal Dump Mode 176
4.9 Resistance Checks 177
....4.9.02 Printhead Interconnect Diagram: Control Board to
Printhead 178
....4.9.03 Line Feed Motor Resistance 179
....4.9.04 Space Motor Resistance 180
A Reference Charts
General Information 181
A.2 Index To Charts 182
....Interconnect Diagram 183
....A.2.01 Main Controller Board (AKGI) 184
....A.2.02 Operator Panel Board (LEOP) 185
....A.2.03 Power Supply Assembly 186
....A.2.04 Space Motor Board 187
....A.2.05 RS232-C Serial Interface Board (LXHI) Option 188
B Illustrated Parts Listing
General Information 189
....B.1.02 Definition of Terms 190
....B.1.03 Parts Ordering Information 191
B.2 Charts 192
....Board Overview 193
....B.2.01 Printer 194
....B.2.02 Upper Cover Assembly 195
....B.2.03 Printer General Assembly 196
....B.2.04 Printer Unit (1 of 3) 197
....B.2.05 Printer Unit (2 of 3) 198
....B.2.06 Printer Unit (3 of 3) 199
....B.2.07 Carriage Assembly 200
....B.2.08 Options 201
....B.2.09 Option Parts 202
....B.2.10 Consumables 203
....B.2.11 Packing Materials 204
....B.2.12 Documentation 205
....B.2.13 Service Training Kit Revision List 206

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Service Guide ML590/ML591
Chapter 0 About This Manual
This document may not be reproduced without the 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.
Written and produced by the Okidata Technical Training Group
Please address any comments on this publication to:
Technical Training Group
Okidata
532 Fellowship Road
Mount Laurel, NJ 08054-3499
Fax Number: [phone], 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.; marque depose de
Oki Electric Industry Company, Ltd.
OkiSmart Paper Handling is a trademark of Oki Electric Industry Company, Inc.
PLUG 'n PRINT is a registered trademark of Oki America, Inc.; marque deposee de Oki America,
Inc.
Bitstream is a registered trademark of Bitstream Incorporated.
Epson is a registered trademark of Seiko Epson Corporation.
IBM is a registered trademark of International Business Machine Corporation.
MS-DOS is a registered trademark of Microsoft Corporation.
PC is a registered trademark of International Business Machine Corporation.
Proprinter is a registered trademark of International Business Machine Corporation.
Windows is a trademark of Microsoft Corporation.
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 ML590/ML591
Chapter 0 About This Manual
© 1994 by Okidata All rights reserved.
First Edition October, 1992 P/N 59256301
Second Revision March, 1993
Third Revision August, 1993
Second Edition April, 1994 P/N 59256302
Fourth Revision April, 1994
Third Edition November, 1994 P/N 59256303
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)

Page: 4
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.1.01 General Information
The Microline 590 and Microline 591 are letter quality dot-matrix printers which utilize OKISMART paper
handling. Patented Okidata technology does away with the manual head gap adjustment. The Microline
590/591 actually "reads and learns" the media you feed in, then automatically adjusts the head gap to the
optimum distance. This auto-gapping process leads to longer printhead life.
An optional, user-installable Color Kit (coupled with a customer-provided color software package) allows
the printers to add impact to graphics, charts, transparencies and text presentations.
Additional options include the Bottom Feed Push Tractor, Cut-Sheet Feeder, Pull Tractor and Serial
Interface Board.
The Microline 590 is an 80 column printer.
The Microline 591 is a 132 column printer.
Okidata's extended two year limited warranty covers the parts, labor and printhead on both printers.
The following items are included with the printer:
OKISMART Typer - software which provides the flexibility for the Microline 590/591 to function like a
typewriter on checks, labels and envelopes.
OKISMART Panel - a utility program that lets you control selected printer functions from your personal
computer.
Scalable Fonts - 14 scalable fonts, available on diskette.
Note: The OkiSmart software includes three programs:
1. OkiSmart Control
2. OkiSmart Panel Emulator
3. OkiSmart Setup
Refer to the Printer Handbook for more information.
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 ML590/ML591
Chapter 1 Product Specifications
1.2 PHYSICAL SPECIFICATIONS
1.2.01 Dimensions
Note: Dimensions INCLUDE the platen knob, acoustic cover, and paper separator.
Microline 590
Width: 18.35 inches (466 millimeters)
Depth: 17.24 inches (438 millimeters)
Height: 6.52 inches (165 millimeters)
Microline 591
Width: 24.41 inches (620 millimeters)
Depth: 17.24 inches (438 millimeters)
Height: 6.52 inches (165 millimeters)
1.2.02 Printer Weight
Microline 590
16.5 pounds (6.5 kilograms)
Microline 591
19.8 pounds (8.9 kilograms)
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)

Page: 6
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.3 POWER REQUIREMENTS
1.3.01 Input Power
120 VAC: +5.5 / -15%
230/240 VAC: +10 / -14%
1.3.02 Power Consumption
Operating: 110 VA
Idle: 40 VA
1.3.03 Power Frequency
120 VAC: 60 Hz +/- 2%
230/240 VAC: 50/60 Hz +/- 2%
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)

Page: 7
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.4 ENVIRONMENTAL CONDITIONS
1.4.01 Acoustic Rating
Letter Quality Mode: 53 dBA
Quiet Mode: 50 dBA
1.4.01 Altitude
10,000 feet (3,050 meters)
1.4.03 Ambient Temperature and Relative Humidity (RH)
While operating: 41° to 104° F (5° to 40° C)
Operating humidity: 20% to 80% RH
While in storage: 14° to 122° F (-10° to 50° C)
Storage humidity: 5% to 95% RH
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)

Page: 8
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.5 AGENCY APPROVALS
1.5.01 Listings
UL No: UL Standard No. 1950
CSA No: CSA Standard 22.2-950
FCC: FCC Certified per Part 15, Subject J, Class B
IEC: IEC 950
VDE: VDE 0805 VDE 0875 Class B
BS: BS 7002
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)

Page: 9
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.6.01 Character Matrix Sizes
Table of Print Speed and Character Matrix
Mode LQ Utility High Speed Draft
Speed 120 (12 cpi) 360 (12 cpi) 450 (15 cpi)
Matrix (H x V) 29 x 18 9 x 17 7 x 17
Print Speed at Different CPI for the ML 590
Mode CPI CPS Horiz. DPI Vert DPI IPS
Utility 10 300 120 180 30
12 360 120 180 30
15 450 120 180 30
17.1 257 240 180 15
20 300 240 180 15
LQ 10 100 360 180 10
12 120 360 180 10
15 150 360 180 10
17.1 171 360 180 10
20 200 360 180 10
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)

Page: 10
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.6.02 Characters Per Line
Microline 590
Characters Per
Line Characters Per
Inch Utility Letter Quality
80 10 164 65
96 12 161 65
120 15 148 65
136 17.1 96 65
160 20 95 65
Microline 591
Characters
Per Line Characters
Per Inch Utility Letter Quality
136 10 105 40
163 12 96 40
204 15 88 40
233 17.1 59 40
272 20 59 40
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)

Page: 11
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.6.03 Character Pitches
5, 6, 8.5, 10, 12, 15, 17.1, 20
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)

Page: 12
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.6.04 Character Sets
Standard ASCII
EPSON Character Set I & II
IBM Character Set I, II & All Characters
Foreign Character Substitution
International Character Sets
Code Page 850, 860, 863 and 865
Bar Code:
Code 39
UPC A
UPC E
EAN 8
EAN 13
Interleaved 2 of 5
Code 128
POSTNET
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)

Page: 13
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.6.05 Printer Emulations
Note: The emulations are co-resident
Epson LQ
IBM XL 24E (AGM)
IBM Proprinter
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)

Page: 14
Service Guide ML590/ML591
Chapter 1 Product Specifications
1.6.06 Fonts
Letter Quality
Courier
Letter Gothic
Prestige
Orator
Roman
Swiss
Draft Utility
High Speed Draft (15 cpi)
Bar Code
Code 39
UPC A
UPC E
EAN 8
EAN 13
Interleaved 2 of 5
Code 128
POSTNET
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)