Epson LQ 670 - B/W Dot-matrix Printer User manual

EPSON
IMPACT DOT MATRIX PRINTER
EPSON LQ-670
SERVICE MANUAL
SEIKO EPSON CORPORATION
4007875

ii
NOTICE
All rights reserved. Reproduction of any part of this manual in any form whatsoever
without SEIKO EPSON’s express written permission is forbidden.
The contents of this manual are subjects to change without notice.
All efforts have been made to ensure the accuracy of the contents of this manual.
However, should any errors be detected, SEIKO EPSON would greatly appreciate
being informed of them.
The above notwithstanding SEIKO EPSON can assume no responsibility for any errors
in this manual or the consequences thereof.
EPSON is a registered trademark of SEIKO EPSON CORPORATION.
General Notice:
Other product names used herein are for identification purposes only and may be
trademarks or registered trademarks of their respective companies.
Copyright 1997 by SEIKO EPSON CORPORATION
Nagano, Japan

iii
PRECAUTIONS
Precautionary notations throughout the text are categorized relative to 1) personal injury and 2)
damage to equipment.
WARNING Signals a precaution which, if ignored, could result in serious or fatal personal injury.
Great caution should be exercised in performing procedures preceded by
WARNING Headings.
CAUTION Signals a precaution which, if ignored, could result in damage to equipment.
The precautionary measures itemized below should always be observed when performing
repair/maintenance procedures.
WARNING
1. ALWAYS DISCONNECT THE PRODUCT FROM BOTH THE POWER SOURCE AND
PERIPHERAL DEVICES PERFORMING ANY MAINTENANCE OR REPAIR PROCEDURES.
2. NO WORK SHOULD BE PERFORMED ON THE UNIT BY PERSONS UNFAMILIAR WITH
BASIC SAFETY MEASURES AS DICTATED FOR ALL ELECTRONICS TECHNICIANS IN
THEIR LINE OF WORK.
3. WHEN PERFORMING TESTING AS DICTATED WITHIN THIS MANUAL. DO NOT
CONNECT THE UNIT TO A POWER SOURCE UNTIL INSTRUCTED TO DO SO. WHEN THE
POWER SUPPLY CABLE MUST BE CONNECTED, USE EXTREME CAUTION IN WORKING
ON POWER SUPPLY AND OTHER ELECTRONIC COMPONENTS.
CAUTION
1. REPAIRS ON EPSON PRODUCT SHOULD BE PERFORMED ONLY BY EPSON CERTIFIED
REPAIR TECHNICIAN.
2. MAKE CERTAIN THAT THE SOURCE VOLTAGE IS THE SAME AS THE RATED VOLTAGE,
LISTED ON THE SERIAL NUMBER/RATING PLATE. IF THE EPSON PRODUCT HAS A
PRIMARY AC RATING DIFFERENT FROM AVAILABLE POWER SOURCE, DO NOT
CONNECT IT TO THE POWER SOURCE.
3. ALWAYS VERIFY THAT THE EPSON PRODUCT HAS BEEN DISCONNECTED FROM THE
POWER SOURCE BEFORE REMOVING OR REPLACING PRINTED CIRCUIT BOARDS
AND/OR INDIVIDUAL CHIPS.
4. IN ORDER TO PROTECT SENSITIVE MICROPROCESSORS AND CIRCUITRY, USE
STATIC DISCHARGE EQUIPMENT, SUCH AS ANTI-STATIC WRIST STRAPS, WHEN
ACCESSING INTERNAL COMPONENTS.
5. REPLACE MALFUNCTIONING COMPONENTS ONLY WITH THOSE COMPONENTS BY
THE MANUFACTURE; INTRODUCTION OF SECOND-SOURCE ICs OR OTHER
NONAPPROVED COMPONENTS MAY DAMAGE THE PRODUCT AND VOID ANY
APPLICABLE EPSON WARRANTY.

iv
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.

v
REVISION SHEET
Revision Issued Data Contents
Rev. A May 28, 1997 First issue

vi
TABLE OF CONTENTS
CHAPTER 1. GENERAL DESCRIPTION
CHAPTER 2. OPERATING PRINCIPLES
CHAPTER 3. DISASSEMBLY AND ASSEMBLY
CHAPTER 4. ADJUSTMENT
CHAPTER 5. TROUBLESHOOTING
CHAPTER 6. MAINTENANCE
APPENDIX

Chapter 1
Product Descriptions
1.1 Specifications.......................................................................................................1-1
1.1.1 Features................................................................................................................................... 1-1
1.2 Hardware Specifications......................................................................................1-3
1.2.1 Printing Method ...................................................................................................................... 1-3
1.2.2 Printing Specifications........................................................................................................... 1-4
1.2.3 Paper Handling Specifications.............................................................................................. 1-5
1.2.4 Paper Specification ................................................................................................................ 1-6
1.2.5 Printable Area ....................................................................................................................... 1-10
1.2.6 Ribbon Cartridge .................................................................................................................. 1-14
1.2.7 Input data buffer................................................................................................................... 1-14
1.2.8 Electrical Specification ........................................................................................................ 1-14
1.2.9 Reliability............................................................................................................................... 1-14
1.2.10 Environmental Condition................................................................................................... 1-15
1.2.11 Safety Approvals................................................................................................................. 1-15
1.2.12 CE Marking.......................................................................................................................... 1-15
1.2.13 Acoustic Noise.................................................................................................................... 1-15
1.3 Firmware Specification ......................................................................................1-16
1.3.1 Control Codes and Fonts..................................................................................................... 1-16
1.3.2 Interface Specification ......................................................................................................... 1-18
1.3.2.1 Parallel interface (Forward channel) .......................................................................1-18
1.3.2.2 Parallel Interface (Reverse channel)....................................................................... 1-20
1.3.2.3 Optional Interface.................................................................................................... 1-21
1.3.2.4 Interface Selection................................................................................................... 1-21
1.3.2.5 Manual selection...................................................................................................... 1-21
1.3.2.6 Automatic selection.................................................................................................1-21
1.3.2.7 Interface state and interface selection..................................................................... 1-21
1.3.3 Prevention Hosts from Data Transfer Timeout..................................................................1-21
1.4 Operation.............................................................................................................1-22
1.4.1 Control Panel ........................................................................................................................ 1-22
1.4.1.1 Usual Operation ......................................................................................................1-22
1.4.1.2 Switches..................................................................................................................1-24
1.4.1.3 Indicators(LED) .......................................................................................................1-25
1.4.1.4 Buzzer .....................................................................................................................1-26
1.4.2 Default Setting ...................................................................................................................... 1-27
1.4.3 Bi-d Adjustment.................................................................................................................... 1-28
1.4.4 Initialization........................................................................................................................... 1-29
1.4.5 Errors..................................................................................................................................... 1-29
1.5 Main Components...............................................................................................1-30
1.5.1 C214 Main Board .................................................................................................................. 1-30
1.5.2 C214PSB Board .................................................................................................................... 1-30
1.5.3 C214 PNL Board.................................................................................................................... 1-31
1.5.4 Printer Mechanism ............................................................................................................... 1-31
1.5.5 Housing ................................................................................................................................. 1-31

Chapter 1 Product Description
Rev. A 1-1
1.1 Specifications
This specifications provide characteristics of the serial impact dot matrix printer LQ-670.
1.1.1 Features
LQ-670 is a 24pin serial impact dot matrix printer for the VAR(value added reseller) market.
The major features of this printer are;
Columns :106 columns (10cpi)
Printing Speed :High speed draft 300cps
:Draft 250cps
:LQ 83cps at 10cpi
Feeding Method :Friction feed (front manual, rear CSF)
:Push tractor feed (rear)
Feeder :Rear push tractor
CSF Bin1/Bin2 (Option)
Roll paper holder (Option)
Paper/Media :Single sheet, Continuous paper, Multi part paper, Envelope, Card,
Label and Roll paper.
Fonts :9LQ & 1 Draft Bitmap and 4 Scarable typefaces
:8 Bar code fonts
Character tables :Standard version 11 tables
NLSP version 20 tables
Input buffer :64 Kbytes
Acoustic noise :55dB(A) (ISO7779 pattern)
Reliability :Total print volume 6.5 million lines(except print head)
:(MTBF) 5000 POH
:Print head life 200 million strokes/wire
:Ribbon life 2 million characters
Interface :Bi-directional parallel interface (IEEE-1284 nibble mode supported)
Type B/I/F level 2 (Option)
Control code :ESC/P 2 and IBM 2390 Plus emulation
Copy capability :1 original + 4 copies
Control panel functions :Font, Condensed, Pause, Tear off, Bin, LF/FF, Load/Eject, Micro Adjust
and the default settings
Printable area :70 lines are available at A4.
(Top margin 0 mm setting and Bottom margin 0 mm setting are available)
I/F Connector
Push Tractor
Stacker
Paper Guide
Edge Guide
Control Panel
Ribbon Cartridge
Power Switch
Printer Cover
Print Head
Adjust Lever
Release lever
Paper Feed Knob
Figure 1-1. Exterior of LQ-670

LQ-670 Service Manual
Rev. A
1-
2
Consumables and optional units
Name Part Number
Ribbon cartridge S015016
High capacity cut sheet feeder (Bin1) C806781 (EAI version)
High capacity cut sheet feeder (Bin1) C806782 (Non-EAI version)
Second bin cut sheet feeder (Bin2) C806791 (EAI version)
Second bin cut sheet feeder (Bin2) C806792 (Non-EAI version)
Roll paper holder #8310
Serial I/F card C82305* / C82306*
32KB intelligent serial I/F card C82307* / C82308*
32KB intelligent parallel I/F card C82310* / C82311*
Local Talk I/F card C82312*
32KB IEEE-488 I/F card C82313*
Coax I/F card C82314*
Twinax I/F card C82315*
Ethernet I/F card C82331*
IEEE-1284 parallel I/F card C82345*
Multi Protocol Ethernet I/F card C82346*
Note*) : The number represented by an asterisk varies, depending on the country.
Table 1-1. Consumables and Optional Units

Chapter 1 Product Description
Rev. A 1-
3
1.2 Hardware Specifications
This section describes hardware specification for the LQ-670.
1.2.1 Printing Method
Printing Method : Impact dot matrix
Number of pins : 24 pins
Print pin arrangement : 12x2 staggered
Print pin diameter : 0.0079 inch (0.20 mm)
Color : Black
Print direction : Bi-direction with logic seeking
Head Center
Figure 1-2. Pin Configuration

LQ-670 Service Manual
Rev. A
1-
4
1.2.2 Printing Specifications
Copy capability :1 original + 4 copies
Print speed and printable columns
Printing Mode Character Pitch Printable Columns Print Speed(cps)
Normal Copy
High speed Draft 10cpi 106 300 200
Draft 10cpi 106 250 167
12cpi 127 300 200
15cpi 159 375 250
Draft condensed 17cpi 181 214 143
20cpi 212 250 167
LQ 10cpi 106 83 70
12cpi 127 100 83
15cpi 159 125 104
LQ condensed 17cpi 181 143 119
20cpi 212 167 139
Note) When the power supply voltage drops to the lower limit, the printer stops printing and then starts
printing the rest of that line again but at the slower speed than before.
Note) When the head temperature rises to the upper limit, the printer stops printing. When the head
temperature falls to the normal level, the printer starts printing again but slower than before.
Resolution
Printing Mode Horizontal density Vertical density Adjacent dot print
High speed draft 90dpi 180dpi No
Draft 120dpi 180dpi No
Draft condensed 240dpi 180dpi No
LQ 360dpi 180dpi N0
8 pins bit image 60, 80, 90 or 120dpi 60dpi Yes
120 or 240dpi 60dpi No
24 pins bit image 60,90,120 or 180dpi 180dpi Yes
360dpi 180dpi No
Raster graphics 180 or 360dpi 180 or 360dpi Yes
Control code : ESC/P 2 and IBM 2390 Plus emulation (Refer to control code)
Table 1-2. Print Speed and Printable Columns
Table 1-3. Resolution

Chapter 1 Product Description
Rev. A 1-
5
1.2.3 Paper Handling Specifications
Feeding method :Friction feed (front manual, rear CSF)
Push tractor feed (rear)
Feeder :Rear push tractor
CSF Bin1/Bin2 (Option)
Roll paper holder(Option)
Paper path :Manual Insertion Front in, front out
CSF Rear in, front out
Tractor Rear in, front out
Line Spacing :1/6 inch or programmable in increments of 1/360 inch
Feed speed :Refer to the table 1-4.
Release Lever :The release lever must be set according to the table 1-5.
Paper thickness lever :The paper thickness lever must be set at the proper position according to the
table 1-6.
Normal mode Copy mode
1/6 inch feed 60 msec 70 msec
Continuous feed 0.127MPS(m/sec)
5.0 IPS(inches/sec) 0.092 MPS(m/sec) 3.6 IPS(inches/sec)
Lever Position Paper path/Feeder Paper/Media
Friction Manual insertion(front) Cut sheet(Single sheet& Muti part)
Card
CSF Bin1 Cut sheet(Single sheet & Multi part)
Envelope, Card
CSF Bin2 Cut sheet(Single sheet)
Roller paper holder Roll paper
Tractor Push tractor feed(rear) Continuous paper(Single sheet & Multi
part)
Lever Position Paper thickness (inch) Paper thickness (mm)
Minimum Maximum Minimum Maximum
0 0.0024 0.0047 0.065 0.12
1 0.0047 0.0075 0.12 0.19
2 0.0075 0.0102 0.19 0.26
3 0.0102 0.0126 0.26 0.32
4 0.0126 0.0142 0.32 0.36
5 0.0142 0.0157 0.36 0.40
6 0.0157 0.0205 0.40 0.52
Table 1-4. Feeding Speed
Table 1-5. Release Lever Position
Table 1-6. Paper Thickness Lever Position

LQ-670 Service Manual
Rev. A
1-
6
1.2.4 Paper Specification
This section describes printable area and types of paper that can be used in this printer.
Cut Sheets
The following table shows specification for cut sheets.
Front Entry(Manual Insertion) Rear Entry(CSF bin1) Rear Entry(CSF bin2)
Minimum Maximum Minimum Maximum Minimum Maximum
Width (inch) 3.6 11.7 3.9 11.7 3.9 11.7
(mm) 91 297 100 297 100 297
Length (inch) 3.5 16.5 3.6 16.5 8.3 16.5
(mm) 90 420 92 420 210 420
Thickness(inch) 0.0025 0.0055 0.0025 0.0055 0.0025 0.0055
(mm) 0.065 0.14 0.065 0.14 0.065 0.14
Weight (g/m2)529052905290
(lb) 14 24 14 24 14 24
Quality Plain paper, Reclaimed paper, Not curled, not folded, not crumpled.
Note): Printing on reclaimed paper is available only under the normal temperature and humidity condition.
Front Entry (Manual Insertion) Rear Entry (CSF)
Minimum Maximum Minimum Maximum
Width (inch) 3.6 11.7 3.9 11.7
(mm) 91 297 100 297
Length (inch) 3.5 16.5(11.7) 3.6 16.5
(mm) 90 420(297)
( ):Value of line
glue one side of
form.
92 420
Copies 1 original + 4 copies 1 original + 4 copies
Total thickness (inch) 0.0047 0.015 0.0047 0.015
(mm) 0.12 0.39 0.12 0.39
Weight (g/m2)40 58 40 58
(one sheet of multi part) (lb) 12 15 12 15
Quality Plain paper, Reclaimed paper
Not curled, not folded, not crumpled Plain paper, Reclaimed paper Not curled, not folded, not crumpled
Jointing Line glue at the top or one side of
form Line glue at the top of form
Note): Printing on multi part. Don’t use CSF 2nd bin.
Table 1-7. Cut Sheet (Single sheet, Not Multi Part)
Table 1-8. Cut Sheet (Multi Part)

Chapter 1 Product Description
Rev. A 1-
7
Envelope
Front Entry (Manual Insertion) Rear Entry (CSF)
Minimum Maximum Minimum Maximum
Envelope Width (inch) 6.5 6.5
(No.6) (mm) 165 165
Length (inch) 3.6 3.6
(mm) 92 92
Envelope Width (inch) 9.5 9.5
(No.10) (mm) 241 241
Length (inch) 4.1 4.1
(mm) 105 105
Total thickness (inch) 0.0063 0.0197 0.0063 0.0197
(mm) 0.16 0.52 0.16 0.52
The difference of thickness at the
printable area is within 0.0098 inch
(0.25mm)
The difference of thickness at the
printable area is within 0.0098 inch
(0.25mm)
Weight (g/m2)45 91 45 91
(lb) 12 24 12 24
Quality BOND paper, PLANE paper or AIR
MAIL. No glue at a flap, Not curled,
not folded, not crumpled
BOND paper, PLANE paper or AIR
MAIL. No glue at a flap, Not curled,
not folded, not crumpled
Note1) : Printing on envelope is available only under normal temperature and humidity conditions.
Note2): Set the longer side of envelope horizontally.
Note3): Don’t use CSF 2nd bin.
Card
Front Entry (Manual Insertion) Rear Entry(CSF)
Minimum Maximum Minimum Maximum
Width (inch) 4.1 5.8 4.1 5.8
(mm) 105 148 105 148
Length (inch) 4.1 5.83 4.1 5.8
(mm) 105 148 105 148
Thickness (inch) 0.0087 0.0087
(mm) 0.22 0.22
Weight (g/m2) 192 192
(lb) 51 51
Quality Plain paper, Reclaimed paper
Not curled, not folded, not crumpled Plain paper, Reclaimed paper Not curled, not folded, not crumpled
Note1) : Printing card is available only under normal temperature and humidity conditions.
Note2): Don’t use CSF 2nd bin.
Table 1-9. Envelope Specification
Table 1-10. Card Specification

LQ-670 Service Manual
Rev. A
1-
8
Continuous paper (Single sheet and Multi part)
Rear Entry (Tractor)
Minimum Maximum
Width (inch) 4 12
(mm) 101.6 304.8
Length(one page) (inch) 4 22
(mm) 101.6 558.8
Copies 1 original + 4 copies
Total thickness (inch) 0.0025 0.015
(mm) 0.065 0.39
Weight (g/m2)52 82
(not multi part) (lb) 14 22
Weight (g/m2)40 58
(one sheet of multi part) (lb) 12 15
Quality Plain paper, Reclaimed paper
Carbonless multi part paper
Jointing Point glue or paper staple(both side)
Continuous paper with Labels
Rear Entry (Tractor)
Minimum Maximum
Label size See the figure below.
Base sheet width (inch) 4 12
(mm) 101.6 304.8
Base sheet length (inch) 4 22
(one page) (mm) 101.6 558.8
Base sheet (inch) 0.0028 0.0035
Thickness (mm) 0.07 0.09
Total thickness (inch) 0.0063 0.0075
0.16 0.19
Label weight (g/m2)68
(lb) 17
Quality A VERY CONTINUOUS FORM LABELS, A VERY MINI-LINE
LABELS or the same quality labels
Note) : Printing on label is available only under the normal temperature and humidity conditions.
Note): The base sheet of labels must be continuous paper.
Table 1-11. Continuous Paper (Single Sheet and Multi Part)
Table 1-12. Continuous Paper with Labels
2.5 inch (63.5mm) min.
15/16 inch
(23.8mm)
min.
Label
R 0.1 inch(2.5mm) min.
Figure 1-3. Label Size

Chapter 1 Product Description
Rev. A 1-
9
Roll paper
Rear Entry (Roll paper holder)
Minimum Maximum
Width (inch) 8.5
(mm) 216
Length (inch) -----
(mm)
Thickness (inch) 0.0028 0.0035
(mm) 0.07 0.09
Weight (g/m2)52 82
(lb) 14 22
Quality Plain paper, Reclaimed paper. Not curled, not folded, not
crumpled.
Table 1-13. Roll Paper Specification

LQ-670 Service Manual
Rev. A
1-1
0
1.2.5 Printable Area
Cut sheets
Single sheet Multi part
PW (Width) (Refer to section 1.2.4) (Refer to section 1.2.4)
PL (Length) (Refer to section 1.2.4) (Refer to section 1.2.4)
LM (Left margin) 3 mm or more(PW<=297mm) 3 mm or more(PW<=297mm)
RM (Right margin) 3 mm or more(PW<=297mm) 3 mm or more(PW<=297mm)
TM (Top margin) 0.0mm or more 0.0mm or more
BM (Bottom margin) 0.0mm or more 0.0mm or more
Printable Area
Figure 1-4. Printable Area for Cut Sheet
Table 1-14. Printable Area for Cut Sheet

Chapter 1 Product Description
Rev. A 1-11
Envelope and card
Envelope Card
PW (Width) (Refer to section 1.2.4) (Refer to section 1.2.4)
PL (Length) (Refer to section 1.2.4) (Refer to section 1.2.4)
LM (Left margin) 3 mm or more 3 mm or more
RM (Right margin) 3 mm or more 3 mm or more
TM (Top margin) 0.0mm or more *1 0.0mm or more *1
BM (Bottom margin) 0.0mm or more 0.0mm or more
Note *1) : When loading the paper from CSF, TM(Top margin) is 4.2 mm or more.
Printable Area
LM
TM
RM
BM
Figure 1-5. Printable Area for Envelope
Printable Area
Figure 1-6. Printable Area for Card
Table 1-15. Printable Area for Envelope and Card

LQ-670 Service Manual
Rev. A
1-1
2
Continuous paper
Continuous paper
PW (Width) (Refer to section 1.2.4)
PL (Length) (Refer to section 1.2.4)
LM (Left margin) 13mm or more
RM (Right margin) 13mm or more
TM (Top margin) 4.2mm or more
BM (Bottom margin) 4.2mm or more
Printable Area
Perforation
Perforation
Figure 1-7. Printable Area for Continuous Paper
Table 1-16. Printable Area for Continuous Paper

Chapter 1 Product Description
Rev. A 1-1
3
Roll paper
Continuous paper
PW (Width) (Refer to section 1.2.4)
PL (Length) (Refer to section1.2.4)
LM (Left margin) 3mm or more
RM (Right margin) 3mm or more
TM (Top margin) 0.0mm or more
BM (Bottom margin) 0.0mm or more
Printable Area
BM
TM
BM
LM
PW
Figure 1-8. Printable Area for Roll Paper
Table 1-17. Printable Area for Roll Paper