OKIDATA ML380 User manual

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Page: 1
Service Guide ML380
Chapter 0 About This Manual
ML380
Dot Matrix Printer
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 ML380
0 About This Manual
Front Cover 1
Manual Copyright 2
1 Product Specifications
1.1 Overview 3
1.2 Physical Specifications 4
1.3 Power Requirements 5
1.4 Environmental Conditions 6
1.5 Agency Approvals 7
1.6 Operational Specifications 8
1.7 Paper Specifications 9
1.8 Memory Specifications 10
1.9 Consumables 11
1.10 Options 12
1.11 Reliability 13
2 Principles of Operation
2.1 Principles of Operation - General Information 14
....2.1.02 Microprocessor and Peripheral Circuits 15
....2.1.03 Initialization 16
....2.1.04 Interface Control 17
....2.1.05 Printhead Drive Circuit 18
....2.1.06 Spacing Drive Circuit 19
....2.1.07 Line Feed Circuit 20
....2.1.08 Alarm Circuits 21
....2.1.09 Paper End Detection Circuit 22
....2.1.10 Power Supply 23
2.2 Mechanical Operation - Printhead Mechanism 24
....2.2.02 Spacing 25
....2.2.03 Ribbon Drive 26
....2.2.04 Paper Feed 27
....2.2.05 Paper-End Detection 28
....2.2.06 Semi-Automatic Sheet Feeder (SASF) 29
....2.2.07 Paper Park 30
3 Maintenance & Disassembly
3.1 Maintenance - General Information 31
....3.1.02 Maintenance Tools 32
....3.1.03 Maintenance Precautions 33
3.2 Disassembly/Assembly Procedures - General Information 34
....3.2.01 Paper Separator 35
....3.2.02 Printhead 36
....3.2.03 Upper Cover Assembly 37
....3.2.04 Space Rack 38

Table of Contents Page
....3.2.05 Ribbon Feed Gear Assembly 39
....3.2.06 Mini-Pitch (Space) Belt 40
....3.2.07 Head Connector Assembly 41
....3.2.08 Main Control Board (UMMB) 42
....3.2.09 Operation Panel 43
....3.2.10 Line Feed Motor 44
....3.2.11 Photosensor Assembly (Paper End) 45
....3.2.12 Bail Arms 46
....3.2.13 Carriage Frame 47
....3.2.14 Platen Assembly 48
....3.2.15 Pressure Roller Assembly 49
....3.2.16 Paper Pressure Guide 50
....3.2.17 Tractor Assembly 51
....3.2.18 Microswitch Assembly (SASF) 52
....3.2.19 Microswitch Assembly (Home Position Switch) 53
....3.2.20 Printer Mechanism 54
....3.2.21 Power Supply Unit 55
....3.2.22 Space Motor Assembly 56
....3.2.23 Bottom Paper Guide Lever 57
3.3 Printer Adjustments 58
....3.3.02 Gap Between Platen and Printhead 59
....3.3.03 Space Belt Tension 60
....3.3.04 Key Combinations 61
....3.3.05 Menu Operation / Menu Select Mode - General
Information 62
........From Print Mode 63
........From Power-OFF 64
........Printing the Menu 65
........Sample Menu 66
........Reset Menu to Factory Defaults 67
........Limited Operation 68
........Menu Settings 69
....3.3.06 Top of Form 70
....3.3.07 Paper Park 71
....3.3.08 Paper Tear Off 72
....3.3.09 Resets 73
3.4 Cleaning 74
3.5 Lubrication 75
3.6 Shipping Instructions 76
4 Failure & Repair Analysis
4.1 Failure & Repair Analysis - Introduction 77
....4.1.02 Printer Serial Number Identification 78
....4.1.03 Firmware Revision Identification 79
4.2 Reporting Problems - General Information 80

Table of Contents Page
....4.2.02 Problem Lists 81
....4.2.03 Reporting Methods 82
4.3 Troubleshooting Updates General Information 83
4.4 Troubleshooting Tips 84
....4.4.02 Problem Categories 85
....4.4.03 START HERE Flowchart 86
....4.4.04 Tips for Preventing Image Problems 87
....4.4.05 Common Problems 88
4.5 Abnormal Output 89
4.6 Fault Alarms - General Information 90
....4.6.02 Fault Alarm Lamp Display 91
4.7 Repair Analysis Procedures (RAPS) - Using The RAPS 92
....4.7.02 RAP Index 93
........RAP 01: No Power 94
........RAP 02: Space Operation Does Not Operate Normally 95
........RAP 03: Wrong Character or Missing Dots 96
........RAP 04: Line Feed Trouble 97
........RAP 05: Data Receiving Failure 98
4.8 Printer Tests - General Information 99
....4.8.02 Rolling ASCII Test 100
....4.8.03 Font Test 101
....4.8.04 Serial Interface Loopback Test - General Information 102
........Loopback Connector Configuration Diagram 103
........Procedure 104
........Serial Cable Information 105
........Serial Interface Signal Requirements 106
........Commonly Used Serial Cable Configurations 107
....4.8.05 Hexadecimal Dump Mode 108
4.9 Resistance Checks - General Information 109
....4.9.02 Main Control Board (UMMB) Voltage Check Points 110
....4.9.03 Connectors Block Diagram 111
....4.9.04 Connector Location 112
....4.9.05 Resistance Diagrams - Printhead 113
........Space and Line Feed Motors 114
....4.9.06 Head Cable Connection 115
A Board Diagrams
A1 Board Diagrams - General Information 116
A.2 Index To Charts 117
....A.2.01 Main Control Board (UMMB) Original 118
....A.2.02 Main Control Board (UMMB) Current 119
....A.2.03 RS232-C Serial Module (UMRS) 120
B Illustrated Parts Listing
B.1 Overview - General Information 121
....B.1.02 Definition of Terms 122

Table of Contents Page
....B.1.03 Parts Ordering Information 123
B.2 Charts 124
....B.2.01 Printer 125
....B.2.02 Covers 126
....B.2.03 Printer Unit 127
....B.2.04 Printer Mechanism (1 of 3) 128
....B.2.05 Printer Mechanism (2 of 3) 129
....B.2.06 Printer Mechanism (3 of 3) 130
....B.2.07 Option Parts 131
....B.2.08 Consumables 132
....B.2.09 Packaging 133
....B2.10 Documentation 134
....B.2.11 Service Training Kit Revision List 135

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Service Guide ML380
Chapter 0 About This Manual
Manual Copyright
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.
© 1994 by Okidata All rights reserved.
First Edition August, 1989 P/N 59238701
Second Edition September, 1993 P/N 59238702
Third Edition November, 1994 P/N 59238703
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.
Centronics is a registered trademark of Centronics Inc.
PLUG n PRINT is a registered trademark of Oki America, Inc.; marque deposee de Oki America, Inc.
Epson is a registered trademark of Seiko Epson Corporation.
IBM is a registered trademark of International Business Machine 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)

Page: 3
Service Guide ML380
Chapter 1 Product Specifications
1.1 OVERVIEW
1.1.01 General Information
The Microline 380 is an 80 column, impact dot matrix printer using a 24 pin printhead. It emulates the
Epson LQ printer.
A push tractor is standard. An optional pull tractor is available.
Font and Character Pitch selection is available through the operator panel, printer menu, or through
software (using control codes).
A Centronics Parallel interface is standard. An RS232-C serial module is available as an option.
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 ML380
Chapter 1 Product Specifications
1.2 PHYSICAL SPECIFICATIONS
1.2.01 Dimensions
Width: 15.67 inches (398 millimeters)
Depth: 4.72 inches (120 millimeters)
Height: 13.58 inches (345 millimeters)
NOTE: Dimensions DO NOT INCLUDE the platen knob, acoustic cover, and paper separator.
1.2.02 Weight
17.9 pounds (8.1 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: 5
Service Guide ML380
Chapter 1 Product Specifications
1.3 POWER REQUIREMENTS
1.3.01 Input Power
120 VAC: +5.5 / -15%
220/240 VAC: +5.5 / -15%
Single-phase AC
1.3.02 Power Consumption
Operating: 90 VA
Idle: 30 VA
1.3.03 Power Frequency
120 VAC: 50/60 Hz +/- 2%
220/240 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)