OKIDATA ML172 Series User manual

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Page: 1
Service Guide ML172/ML182 Series
Chapter 0 About This Manual
ML172/ML182 Series
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
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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 ML172/ML182 Series
0 About This Manual
Front Cover 1
Copyright 2
1 General Description & Specifications
1.1 General Description 3
....1.1.1 ML172 4
....1.1.2 ML182 5
....1.1.3 ML182-PLUS 6
....1.1.4 ML182-TURBO 7
1.2 Specifications 8
2 Principles of Operation
2.1 Electrical Principles Of Operation 9
....2.1.1 Power Supply 10
....2.1.2 Control PCB 11
....2.1.3 Interconnect Board 12
....2.1.4 Operator Board 13
2.2 Mechanical Principles Of Operation : Printhead 14
....2.2.2 Head Gap Adjusting Mechanism 15
....2.2.3 Space Mechanism / Operation 16
....2.2.4 Ribbon Feed Mechanism / Operation 17
....2.2.5 Paper Feed Mechanism / Operation 18
....2.2.6 Paper-end Detection Mechanism 19
....2..2.7 Semi-Automatic Sheet Feed (SASF) 20
3 Printer Maintenance
3.1 General Information 21
....Figure 3-1a - ML172 22
....Figure 3-1b - ML182 23
....Figure 3-1c - ML182-PLUS/ML182-TURBO 24
3.2 Maintenance Procedures 25
....3.2.1 Upper Cover 26
....3.2.2 Control Board 27
....3.2.3 Transformer Assembly 28
....3.2.4 Power Supply Board 29
....3.2.5 Operation Board 30
....3.2.6 Printhead 31
....3.2.7 Ribbon Feed Gear Assembly 32
....3.2.8 Space Motor Assembly 33
....3.2.9 Space Rack 34
....3.2.10 Carriage Cable 35
....3.2.11 Printer Mechanism 36
....3.2.12 Linefeed Motor Assembly 37
....3.2.13 Column Indicator Bar 38

Table of Contents Page
....3.2.14 Platen Assembly 39
....3.2.15 Interconnect Board 40
....3.2.16 Paper Chute Assembly 41
....3.2.17 Bottom Paper Guide Assembly 42
....3.2.18 Near-end Lever And Bracket 43
....3.2.19 Bottom Near-end Lever 44
3.3 Adjustments 45
....3.3.2 Space Rack and Roller Gap Adjustment 46
3.4 Printer Self-Tests 47
3.5 Preventive Maintenance 48
4 Interfacing Techniques
4.1 Interfacing Techniques 49
5 Failure Analysis Procedures
5.1 Failure Analysis Procedure 50
....RAP Index 51
........Board layout and Wiring - ML182Plus and ML182Turbo 52
........Board layout and Wiring - ML172 and ML182 53
........Pin Numbers and Signals 54
........Check Points for Printed Circut Boards - 172 55
........Check Points for Printed Circuit Boards - ML182 56
........Check Points for Printed Circuit Boards - ML182Plus and
ML182Turbo 57
........RAP #1: Power is on but carriage does not move 58
........RAP #2: Power LED lights, but the carriage does not
move 59
........RAP #3: Carriage movement is abnormal when power is
turned on 60
........RAP #4: Homing operation is normal, but the indicators
(LED1 to LED9) are abnormal when power is turned on. 61
........RAP #5: Fuse F1 on power supply board (SLPB) blows
when power is turned on. 62
........RAP #6: Fuse F1 on the control board blows when power
is turned on. 63
........RAP #7: Neither spacing nor printing performed while
receiving data. 64
........RAP #8: Spacing is normal, but nothing is printed while
receiving data. 65
........RAP #9: Printer stops printing. 66
........RAP #10: Wrong characters are printed or some
characters are missing. 67
........RAP #11: Some dots are missing. 68
........RAP #12: Print is light. 69
........RAP #13: Line feed is not performed. 70
........RAP #14: Fuse F1 on power supply board blows while
receiving data and printing. 71

Table of Contents Page
........RAP #15: Switch on the operator panel does not work
(Carriage returns to home position when power is turned on). 72
........RAP #16: Paper not fed properly (SASF function). 73
A PCB Referance Charts
Power Supply Board (SLPB) 74
ML172 Control Board (SLMR-51 & SLMR-52) and Operator
Board 75
ML182 Control Board (SLMC) 76
ML182 Control Board (SLMR) and Operator Board 77
ML182-PLUS & ML182-TURBO Control Board (SLMX) and
Operator Boards 78
A PCB Reference Charts
RS232-D Super Speed Serial I/F Board 79
B Parts Compatability Chart
Parts Compatability Chart 80

Page: 2
Service Guide ML172/ML182 Series
Chapter 0 About This Manual
Copyright
All rights reserved. No part of this document may be reproduced in any form without the prior written
permission of OKIDATA.
Every effort has been made to ensure that the information in this document is complete, accurate and up
to date. We do not assume responsibility for errors beyond our control.
© Copyright 1989 by OKIDATA
First Edition May 1989
CENTRONICS is a registered trademark of Centronics Inc.
EPSON is a registered trademark of Seiko Epson Corporation
OKIDATA and MICROLINE are registered trademark of Oki America Inc.
IBM is a registered trademark of International Business Machines, Inc.
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 ML172/ML182 Series
Chapter 1 General Description & Specifications
1.1 GENERAL DESCRIPTION
The Microline 172, 182, 182-PLUS and 182-TURBO Printers are reliable, compact, dot matrix printers
using a 9-wire printhead. These printers use a re-inking cartridge ribbon.
Although these printers are similar in appearance, there are differences in the features that each printer
offers. Lets take a closer look at each 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)

Page: 4
Service Guide ML172/ML182 Series
Chapter 1 General Description & Specifications
1.1.1 ML172
Emulates the IBM Graphics Printer.

Pitch, page length and print mode are set through a MENU.

Switches on the Control Board select default Menu settings. Settings return to default values when

the printer is powered off.
Pull tractor is standard.

Available in two models:

1. Centronics parallel interface, this model will not accept a serial board.
2. RS232-D serial interface. This model can be configured for parallel operation by removing the
Serial Board from the Control 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)

Page: 5
Service Guide ML172/ML182 Series
Chapter 1 General Description & Specifications
1.1.2 ML182
Two models are available, IBM emulation, or Microline emulation.

Available with two interfaces, Centronics Parallel, or RS232-C Serial (9600 Baud, Ready Busy

Protocol). An optional Super Speed Serial board (19.2 Baud, Ready Busy and X-On, X-Off
Protocols) is available.
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 ML172/ML182 Series
Chapter 1 General Description & Specifications
1.1.3 ML182-PLUS
The ML182-PLUS is an enhanced version of the ML182, with the following features:
Push-button front panel which allow the setting of Pitch (10,12 or 17 CPI), and Mode (Near Letter

Quality, Utility and High Speed Draft).
SASF (Semi-Automatic Sheet Feed), which allows single sheets of paper to be automatically loaded

using the bail arm lever.
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)