Epson 670 PREFACE

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PREFACE

This manual describes functions, theory of electrical and mechanical operations, maintenance, and

repair of EPSON LQ-670.

The instructions and procedures included herein are intended for the experience repair technician,

and attention should be given to die precautions on the preceding page. The Chapters are

organized as follows:

CHAPTER 1. GENERAL DESCRIPTION

Provides a general product overview, lists specifications, and illustrates the main components of the

printer.

CHAPTER 2. OPERATING PRINCIPLES

Describes the theory of printer operation.

CHAPTER 3. DISASSEMBLY AND ASSEMBLY

Includes a step-by-step guide for product disassembly and assembly.

CHAPTER 4. ADJUSTMENT

Includes a step-by-step guide for adjustment.

CHAPTER 5. TROUBLESHOOTING

Provides EPSON-approved techniques for troubleshooting.

CHAPTER 6. MAINTENANCE

Describes preventive maintenance techniques and lists lubricants and adhesives required to

service the equipment.

APPENDIX

Describes connector pin assignments, circuit diagrams, circuit board component layout and

exploded diagram.

The contents of this manual are subject to change without notice.

Contents

Main NOTICE Copyright 1997 by SEIKO EPSON CORPORATION Nagano, Japan PRECAUTIONS WARNING CAUTION WARNING CAUTION PREFACE Page Page Chapter 1 Product Descriptions 1.1 Specifications 1.1.1 Features Page 1.2 Hardware Specifications 1.2.1 Printing Method 1.2.2 Printing Specifications Rev. A 1- 1.2.3 Paper Handling Specifications 1.2.4 Paper Specification Rev. A 1- Note1) Note3): Note2): Note2): Page Page 1.2.5 Printable Area Rev. A 1-11 Note *1) Printable Area Printable Area BM 1.2.6 Ribbon Cartridge 1.2.7 Input data buffer Note*) 1.2.8 Electrical Specification 1.2.9 Reliability 1.2.10 Environmental Condition 1.2.11 Safety Approvals 1.2.12 CE Marking 1.2.13 Acoustic Noise 1.3 Firmware Specification 1.3.1 Control Codes and Fonts Page 1.3.2 Interface Specification 1.3.2.1 Parallel interface (Forward channel) Page 1.3.2.2 Parallel Interface (Reverse channel) Note*): Rev. A 1-21 1.3.2.3 Optional Interface 1.3.2.4 Interface Selection 1.3.3 Prevention Hosts from Data Transfer Timeout 1.4 Operation 1.4.1 Control Panel 1.4.1.1 Usual Operation Page 1.4.1.2 Switches 1.4.1.3 Indicators(LED) 1.4.1.4 Buzzer 1.4.2 Default Setting Notes. 1.4.3 Bi-d Adjustment 1.4.4 Initialization 1.4.5 Errors 1-3 1.5 Main Components 1.5.1 C214 Main Board 1.5.2 C214PSB Board Page Chapter 2 Operating Principles Rev. A 2-1 2.1 Printer Mechanism Operation 2.1.1 Printing Mechanism Page 2.1.2 Carriage Mechanism Page 2.1.3 Ribbon Advance Mechanism 2- 2.1.4 Paper Advance Mechanism 2.1.4.1 Paper Advance Mechanism 2.1.4.2 Paper Advance Detector Mechanism Page 2.1.4.3 Release Lever Mechanism Release Lever Tractor Gear Roller, PF Drive Tractor Transmission Gear 2.1.5 Platen Gap Adjustment Rev. A 2-11 2.2 Power Supply Operation 2.2.1 Power Supply Circuit 2.2.1.1 Power Supply Overview 2.2.1.2 Power Supply Circuit Operation Rev. A 2-1 2.2.2 Control Circuit 2.2.2.1 Operating Principles of the Control Circuit 2.2.2.2 EEPROM Control Circuit 2.2.2.3 System Reset Circuit 2.2.2.4 Power Off Detector Circuit 2.2.2.5 Print Head Driver Circuit 2.2.2.6 CR Motor Driver Circuit 2.2.2.7 PF Motor Driver Circuit 2.2.2.8 Operation Panel Control Circuit Page Chapter 3 Disassembly and Assembly Page 3.1 Overview 3.1.1 Precautions for Disassembling the Printer 3.1.2 Tools WARNING 3-2 3.1.3 Service Check After Repair 3.1.4 Specifications for Screws 3-4 3.2 Printer Disassembly and Assembly Figure 3-1. Disassembly Flowchart The flowchart below show you the basic order for disassembly. Before disassembling any part of the printer, note the warnings in Section 3.1.1. START 3.2.1 HOUSING, UPPER Removal 3-6 3.2.2 Printer Mechanism Removal 3.2.3 C214 MAIN Board Removal 3.2.4 C214 PSB/PSE Board Removal 3.2.5 EP-ROM Replacement CHECK POINT 3.2.6 Printhead Removal 3.2.7 Ribbon Mask Removal 3.2.8 PAPER EXIT ASSY. Removal 3.2.9 Ribbon Mask Holder Removal 3.2.10 PW Detector (Top) Removal 3.2.11 MOTOR, CR Removal 3.2.12 Carriage Assy. Removal CHECK POINT Page 3.2.12.1 RATCHET, RD Removal 3.2.13 PAPER GUIDE Removal Page Chapter 3 Disassembly and Assembly Rev. A 3-21 3-22 3.2.14 Platen Removal 3.2.15 MOTOR, PF Removal Page 3.2.19 DETECTOR, PE, FRONT Removal 3.2.20 DETECTOR, PE, REAR Removal 3.2.21 LEVER, RELEASE Removal 3.2.22 Tractor ASSY. Removal Page Rev. A 4-1 4.1 Adjustment Overview Note*2) Note*1) 4.1.1 Required Adjustments 4.1.2 Required Adjustment Tools 4.2 Adjusting and Resetting the Printer Do not rotate the platen roller during this adjustment. 4.2.1 Platen Gap Adjustment Rev. A 4- 4.2.2 Factory Setting Page Rev. A 4- 4.2.3 Bi-d Adjustment Page Page 5.1 Overview 5- 5.2 Unit Level Troubleshooting Page Page Page Page Rev. A 5- Page View A R F R L 1-24 :Wire Number C :Common Terminal T:Thermistor Terminal Note*) Rev. A 5-11 5.3 Repairing the Power Supply Circuit Board Page Page 5.4 Repairing the Main Board Page Page 5.5 Repairing the Printer Mechanism Page Page 6.1 Preventive Maintenance Page Appendix A.1 Connector Summary A- Rev. A A- A- Page Page Page Page Page Page Page Page Page A-1 Page A.5 Dimension and Weight EPSON OVERSEAS MARKETING LOCATIONS As of September, 1996