Epson LQ-670 Dot Matrix Printer Service Manual – PDF Download

Description

Epson LQ-670 Dot Matrix Printer Service Manual – PDF Download

Description

🔧 Overview

The Epson LQ-670 Service Manual provides comprehensive technical information and maintenance procedures for the LQ-670 24-pin dot matrix printer. It includes detailed circuit schematics, mechanical disassembly guides, adjustment flowcharts, and diagnostic procedures for reliable repair and calibration.

📋 Table of Contents Highlights

Chapter 1 – Product Description

• Overview of LQ-670 specifications, printing technology, and system configuration.

• Interface options: Parallel (IEEE-1284), Serial, and optional network modules.

• Paper handling system, control panel functions, and firmware logic.

Chapter 2 – Operating Principles

• Mechanical drive system — carriage motor (PM stepper), paper feed motor, timing belt, and platen assembly operation.

• Electronic control — logic circuits, CPU, ROM, RAM, gate arrays, and sensor signals.

• Flowcharts for print head drive timing and control sequences.

Chapter 3 – Disassembly and Assembly

• Step-by-step procedures for removing:

  • Print head assembly

  • Carriage unit and belt tensioner

  • Main logic board and interface panel

  • Power supply unit and control panel

  • Tractor feed, platen, and frame components

• Illustrated diagrams with torque and connector identification.

Chapter 4 – Adjustment

• Print head gap and platen parallelism adjustments.

• Sensor alignment (PE sensor, ASF sensor, home position sensor).

• Adjustment Mode entry via control panel and DIP switch settings.

• Test print patterns and margin calibration methods.

Chapter 5 – Troubleshooting

• Symptom-based troubleshooting tables for:

  • No power / abnormal LED blinking

  • No paper feed or carriage movement

  • Print distortion or uneven characters

  • Interface and logic errors

• Diagnostic self-test modes and error LED pattern list.

Chapter 6 – Electrical Circuit Diagrams

• Full main logic board schematic, sensor input/output tables, connector pinouts, and voltage reference points.

• Power supply regulation flow and transistor/IC identification.

Chapter 7 – Maintenance & Parts

• Preventive maintenance schedule and cleaning instructions.

• Parts list with exploded diagrams (print head, frame, platen, gears, motors, harnesses).

• Lubrication points and recommended greases.

⚙️ Technical Specifications

• Print Method: 24-pin impact dot matrix

• Print Speed: up to 413 cps (10 cpi draft)

• Paper Feed: friction, push tractor, optional pull tractor

• Interfaces: Parallel (IEEE 1284) / Serial RS-232C / optional USB or network

• Buffer Memory: 32 KB standard

• Resolution: 360 × 360 dpi (maximum)

• Power Supply: 120–240 V AC, 50/60 Hz

• Dimensions: 469 × 386 × 221 mm

• Weight: approx. 8.5 kg

🧰 Key Features

• Step-by-step mechanical disassembly procedures.

• Complete schematics and connector pin tables.

• Official Epson adjustment and calibration methods.

• Symptom-based troubleshooting for quick repair.

• Exploded views for accurate parts replacement.

📄 File Details

💡 Why This Manual Is Valuable

• Includes factory-grade adjustment and electrical schematics not available in user guides.

• Enables precise alignment of print head and platen systems.

• Essential for service technicians and electronic repair specialists.

• Saves time with detailed part numbers and troubleshooting flowcharts.