Epson 670 5.5 Repairing the Printer Mechanism

LQ-670 Service Manual

Rev. A 5-1

7

5.5 Repairing the Printer Mechanism

This section provides instruction for repairing the printer mechanism. It describes various problem s,

symptom, likely causes, checkpoints, and solutions.

Symptom Condition Cause Checkpoint Solution

CR motor is

abnormal CR does not move

even the power is

turned on.

Foreign objects

are attached to

mechanism.

Move the timing belt

manually and check if the

motor rotates or not.

Remove the

foreign objects.

CR motor is

defective Measure the coil

resistance of the motor.

3.5Ω±10%.

(Refer to Table 5-5)

•If the motor gets short-

circuit, check if the driver

circuit also got short-

circuit.

Replace CR

motor or main

board.

Carriage does

not move even

after the

power is

turned on.

CR motor rotates,

but carriage does

not move.

The pulley drive

is defective. Check if the pulley is

broken or worn out. Replace the

pulley drive.

Timing belt is

defective. Check if the timing belt is

installed on the carriage,

also, the notched part of

the timing belt is worn out

or not.

Replace the

timing belt or re-

install again.

Carriage moves to

left side a little bit,

but stops.

Carriage does

not move

smoothly.

Check if carriage moves

smoothly by hand. Clean CR guide

shaft and

lubricate it, or

replace the CR

motor.

Carriage stops after

moving to the right

or left edges.

HP sensor is

defective. --- Replace the HP

sensor.

Printing is

abnormal. Carriage moves but

no image is printed. Head FFC is

disconnected or

there is no

continuity.

Check if head FFC is

connected or bent. Replace the

FFC.

Print head is

defective Measure head coil

resistance. 39.3±2.7ΩReplace the print

head(If

necessary

replace the

driver)

The printer does

not print a particular

dot.

Print head is

defective. Check if the head wire is

broken or not. Replace the print

head.

Printing result is

uneven or too light. Print head is

defective Check if the head wire is

broken or not. Replace the print

head.

Abnormal

paper feed. Printing is

performed, but no

paper feed, or

paper feed is not

done smoothly.

Foreign objects

are in the paper

path.

Check the paper path

visually. Remove the

foreign objects.

PF motor is not

driven correctly. Check if foreign objects

are attached to the motor

or drive gear, or gears are

damaged or worn out.

Remove the

foreign objects or

replace the

gears.

Table 5-14. Repairing the Printer Mechanism

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