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Page: 1
Service Guide ML520/521
Chapter 0 About This Manual
ML520 // ML521
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 (
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Table of Contents Page Service Guide ML520/521 0 About This Manual Front Cover 1 Copyright Information 2 1 Product Specifications 1.1.01 General Information 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 - Cut Sheet Feeders 12 ........1.10.02 Pull Tractor Kit 13 ........1.10.04
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Table of Contents Page ........Head Drive Time 39 ........Print Speed 40 ........%Head Overheat Alarm Processing 41 ....2.1.08 Power Supply Circuit 42 2.2 Mechanical Operation - Printhead Mechanism 43 ........Printhead Gap Information 44 ........Interconnect Diagram: Control Board to Printhead 45 ........Line Feed Motor Resistance 46 ........Space Motor Resistance 47 ........Printhead Operation 48 ........Printhead Temperature 49 ....2.2.02 Spacing Mechanism 50 ........Spacing Operation 51 ....2
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Table of Contents Page ....3.2.11 Space Motor and Roller Guide Assemblies 80 ....3.2.12 Carriage Cable 81 ....3.2.13 Space Rack 82 ....3.2.14 Roller/Holder Backup Assembly 83 ....3.2.15 Guide Rail and Adjust Cam 84 ....3.2.16 Left Ground Plate 85 ....3.2.17 Right Ground Plate 86 ....3.2.18 Rear and Cut Sheet Paper Feed Sensor Levers 87 ....3.2.19 Platen Assembly 88 ....3.2.20 Paper Chute Assembly 89 ....3.2.21 Line Feed Motor Assembly 90 ....3.2.22 Reset Spring 91 ....3.2.23 Idle Gear and Change
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Table of Contents Page ....4.4.04 Tips for Preventing Image Problems 123 ....4.4.05 Common Problems 124 4.5 Abnormal Output - Output Samples 125 ....Left Margin Drifting Problem 126 4.6 Fault Alarms 127 ....4.6.02 ALARM/LED Display Troubleshooting Table Index 128 ....4.6.03 ALARM/LED Display Troubleshooting Tables 129 4.7 Repair Analysis Procedures (Raps) 130 ....4.7.02 RAP Index 131 ........RAP 01 No Power Supplied to Printer 132 ........RAP 02 No Spacing Operation 133 ........RAP 03 Printhead
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Table of Contents Page ........Format 165 ........Current Part Numbers 166 ....B.1.02 Definition of Terms 167 ....B.1.03 Parts Ordering Information 168 B.2 Charts 169 ........Overview 170 ....B.2.01 Printer 171 ....B.2.02 Upper Cover Assembly 172 ....B.2.03 Printer General Assembly 173 ....B.2.04 Printer Unit 174 ....B.2.05 Printer Unit 175 ....B.2.06 Printer Unit 176 ....B.2.07 Carriage Assembly 177 ....B.2.08 Options 178 ....B.2.09 Option Parts 179 ....B.2.10 Consumables 180 ....B.2.11 Packing
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Page: 2 Service Guide ML520/521 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. © 1994 by Okidata All rights reserved. First Edition February, 1993 P/N 59257801 Second Edition September, 1993 P/N 59257802 Third Edition December, 1994 P/N 59257803
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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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Page: 3 Service Guide ML520/521 Chapter 1 Product Specifications 1.1.01 General Information The Microline 520 and Microline 521 are letter quality, nine-pin, dot-matrix printers which utilize OKISMART paper handling. Patented Okidata technology does away with the manual head gap adjustment. The printer actually reads and learns the print medium being used, then automatically adjusts the head gap to the optimum distance. This autogapping process leads to longer printhead life. Options includ
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Page: 4 Service Guide ML520/521 Chapter 1 Product Specifications 1.2 PHYSICAL SPECIFICATIONS 1.2.01 Dimensions NOTE: Dimensions INCLUDE the platen knob, acoustic cover, and paper separator. Microline 520 Width: 16.9 inches (43 centimeters) Depth: 14.9 inches (37.8 centimeters) Height: 6.5 inches (16.5 centimeters) Microline 521 Width: 23 inches (58.4 centimeters) Depth: 14.9 inches (37.8 centimeters) Height: 6.5 inches (16.5 centimeters) 1.2.02 Printer Weight Microline 520 17.6 pounds (8.0 kil
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Page: 5 Service Guide ML520/521 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 Local Test: 70 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)
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Page: 6 Service Guide ML520/521 Chapter 1 Product Specifications 1.4 ENVIRONMENTAL CONDITIONS 1.4.01 Acoustic Rating Near Letter Quality Mode Microline 520 54.9 dBA Microline 521 54.4 dBA Utility Mode Microline 520 57.2 dBA Microline 521 56.9 dBA Quiet Mode Microline 520 52.5 dBA Microline 521 52.3 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 degrees Fahrenheit (5 to 40 degrees Celsius) Operating humidity: 20% t
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Page: 7 Service Guide ML520/521 Chapter 1 Product Specifications 1.5 AGENCY APPROVALS 1.5.01 Listings UL No: UL Standard No. 1950 D3 CSA No: CSA Standard 22.2-950 D3 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)
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Page: 8 Service Guide ML520/521 Chapter 1 Product Specifications 1.6 OPERATIONAL SPECIFICATIONS 1.6.01 Character Matrix Sizes Table of Print Speed and Character Matrix Mode Near Letter Quality Utility High Speed Draft Speed 80 (12cpi) 320 (12cpi) 427 (12cpi) Matrix (H x V) 17 x 13 9 x 7 7 x 7 Print Speed at Different CPI for the ML 520/521 Mode CPI CPS Horiz. DPI Vert. DPI IPS 10 427 90 72 42.7 HSD 12 427 108 72 35.6 15 427 135 72 28.5 17.1 427 154 72 25.0 20 427 180 72 21.4 Utility 10 320 120
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Characters Per Line Characters Per Inch 80 10 96 12 120 15 137 17.1 160 20 Microline 521 Characters Per Line Characters Per Inch 136 10 163 12 204 15 233 17.1 272 20 1.6.03 Character Pitches 5, 6, 8.5, 10, 12, 15, 17.1, 20 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, 865 and 437 Line Graphics Bar Code Code 39 UPC A UPC E EAN 8 EAN 13 Interleaved 2 of 5
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1.6.05 Emulations NOTE: The emulations are co-resident Epson FX IBM Proprinter Microline Standard 1.6.06 Fonts Near Letter Quality Courier Utility Gothic High Speed Draft Gothic Bar Code Code 39 UPC A UPC E EAN 8 EAN 13 Interleaved 2 of 5 Code 128 (A, B, C) Postnet 1.6.07 Front Panel Switches SELECT / Menu Micro Feed Up / Down Shift Paper Park Line Feed Pitch Selection FORM FEED / Load Print Quality Selection Top of Form Tear Quiet Reset 1.6.08 Graphics Resolution Graphics Resolution: 288 (horiz
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RS232C Serial 1.6.10 Line Feed Increments Fixed 6 lines per inch (lpi) [0.167 inch (4.23 millimeters)] 8 lines per inch (lpi) [0.125 inch (3.175 millimeters)] Variable n/60 inch n/72 inch n/144 inch n/216 inch 1.6.11 Line Feed Time 65 milliseconds 6 lines per inch (lpi) 6 milliseconds 8 lines per inch (lpi) 1 second 5.0 inches (Continuous paper feed rate) 1.6.12 Menu Mode Switch Action Paper park Prints the entire menu. Line Feed / Reverse Selects Group Function FORM FEED / Load Selects Item Tea
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Paper Park Automatic Paper Loading Forms Tear Off 1.6.15 Paper Loading Auto Loading (Top Feed) Press FORM FEED / Load switch to feed paper to default position 1.6.16 Paper Out Detection Distance from end of paper Rear Feed: 0.5 inches (12.7 mm) Bottom Feed: 0.5 inches (12.7 mm) Top Feed: 0.5 inches (12.7 mm) 1.6.17 Paper Tear Capabilities Forms Tear-0ff (sharp edge on access cover) Metal Tear Bar (with optional bottom feed tractor unit) 1.6.18 Print Method Printhead Type General Information Impa
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1. Printhead Gap Adjustment This is a SERVICE ADJUSTMENT made by a technician. It is covered in Section 3.3 of this Service Handbook. The Adjustment measures 0.014 +/- 0.001 inches 90.35, +/-0.03 mm). 2. Printhead Gap Adjustment This is a MENU ITEM in the SET-UP Group. It fine tunes the automatic setting of the printhead gap. The settings are 0, 1 and -1. Use 1 to darken print (if output is consistently light). Use -1 to lighten print (if output is consistently dark). 3. Gap Control This is a ME
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Used when the same paper is used ALL of the time. Bypasses the automatic head gap adjustment. 1 is the narrowest head setting. 9 is the widest head setting. 1.6.19 Print Modes Near Letter Quality Utility High Speed Draft 1.6.20 Print Speed Table of Print Speed and Character Matrix Mode Near Letter Quality Utility High Speed Draft Speed 80 (12 cpi) 320 (12 cpi) 427 (12 cpi) Matrix (H x V) 17 x 13 9 x 7 7 x 7 Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDA
