Epson Seij98006 Users Manual FRONT
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- SC900 Revision C
- Product Description
- 1.1 Features
- 1.2 Specifications
- 1.2.1 Printing Specifications
- 1.2.2 Options and Consumable Products
- 1.2.3 Paper Specifications
- 1.2.4 Printable Area
- 1.2.5 Ink Cartridge Specifications
- 1.2.6 Electrical Specifications
- 1.2.7 Environmental Condition
- 1.2.8 Reliability
- 1.2.9 Safety Approvals
- 1.2.10 Acoustic Noise
- 1.2.11 CE Marking (220 ~ 240 V version)
- 1.2.12 Physical Specifications
- 1.3 Interface
- 1.4 Control Panel Operation
- 1.5 Error Status
- 1.6 Printer Initialization
- 1.7 Component Layout
- Operating Principles
- Troubleshooting
- Disassembly and Assembly
- Adjustment
- 5.1 Overview
- 5.2 Adjustments
- 5.2.1 Preliminary Operation
- 5.2.2 Market Destination Check
- 5.2.3 Head Actuator Voltage Input
- 5.2.4 Head Angular Adjustment
- 5.2.5 Bi-Directional Adjustment
- 5.2.6 Printhead Cleaning Using the Program
- 5.2.7 Initial Ink Charge
- 5.2.8 Indication of the Counter Value for the Waste Ink Pad
- 5.2.9 Fan Check
- 5.2.10 Paper Gap Adjustment
- 4.2.7.1 Printhead Removal
- 4.2.7.2 CR Motor Removal
- 4.2.7.3 PF Motor Removal
- 4.2.7.4 Pump/ASF Motor and Solenoid Removal
- 4.2.7.5 ASF Unit Removal
- 4.2.7.6 ASF Sensor Removal
- 4.2.7.7 CRHP Sensor Removal
- 4.2.7.8 PE Sensor Removal
- 4.2.7.9 Encoder Belt Sensor Removal
- 4.2.7.10 Carriage Unit Removal
- 4.2.7.11 Pump Unit Removal
- 4.2.7.12 Paper Eject Frame Removal
- 4.2.7.13 Paper Eject Roller Removal
- 4.2.7.14 Platen Removal
- 4.2.7.15 PF Roller Removal
- Maintenance
- Appendix
- Product Description

EPSON Stylus Color 900 (Revision C)
Color ink jet printer
SEIJ98006
®

Notice:
All ri
g
hts reserved. No part of this manual may be reproduced, stored in a retrieval system, or transmitted in any form or by any means,
electronic, mechanical, photocopyin
g
, recordin
g
, or otherwise, without the prior written permission of SEIKO EPSON CORPORATION.
The contents of this manual are subject to chan
g
e without notice.
All effort have been made to ensure the accuracy of the contents of this manual. However, should any errors be detected, SEIKO EPSON
would
g
reatly appreciate bein
g
informed of them.
The above not withstandin
g
SEIKO EPSON CORPORATION can assume no responsibility for any errors in this manual or the consequences
thereof.
EPSON is a re
g
istered trademark of SEIKO EPSON CORPORATION.
General Notice: Other product names used herein are for identification purpose only and may be trademarks or re
g
istered trademarks of their
respective owners. EPSON disclaims any and all ri
g
hts in those marks.
Copyri
g
ht © 1996 SEIKO EPSON CORPORATION. Printed in Japan.

PRECAUTIONS
Precautionary notations throu
g
hout the text are cate
g
orized relative to 1)Personal injury and 2) dama
g
e to equipment.
DANGER
Si
g
nals a precaution which, if i
g
nored, could result in serious or fatal personal injury. Great caution should be exercised in
performin
g
procedures preceded by DANGER Headin
g
s.
WARNING
Si
g
nals a precaution which, if i
g
nored, could result in dama
g
e to equipment.
The precautionary measures itemized below should always be observed when performin
g
repair/maintenance procedures.
DANGER
1. ALWAYS DISCONNECT THE PRODUCT FROM THE POWER SOURCE AND PERIPHERAL DEVICES PERFORMING ANY MAINTENANCE
OR REPAIR PROCEDURES.
2. NOWORK 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.
WARNING
1. REPAIRS ON EPSON PRODUCT SHOULD BE PERFORMED ONLY BY AN EPSON CERTIFIED REPAIR TECHNICIAN.
2. MAKE CERTAIN THAT THE SOURCE VOLTAGES 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.

PREFACE
This manual describes basic functions, theory of electrical and mechanical operations, maintenance and repair procedures of Stylus Color 900. The
instructions and procedures included herein are intended for the experienced repair technicians, and attention should be
g
iven to the precautions on
the precedin
g
pa
g
e. The chapters are or
g
anized as follows:
CHAPTER 1. PRODUCT DESCRIPTIONS
Provides a
g
eneral overview and specifications of the product.
CHAPTER 2. OPERATING PRINCIPLES
Describes the theory of electrical and mechanical operations of the product.
CHAPTER 3. TROUBLESHOOTING
Provides the step-by-step procedures for troubleshootin
g
.
CHAPTER 4. DISASSEMBLY AND ASSEMBLY
Describes the step-by-step procedures for disassemblin
g
and assemblin
g
the
product.
CHAPTER 5. ADJUSTMENTS
Provides Epson-approved methods for adjustment.
CHAPTER 6. MAINTENANCE
Provides preventive maintenance procedures and the lists of Epson-approved
lubricants and adhesives required for servicin
g
the product.
APPENDIX
Provides the following additional information for reference:
• Connector pin assignments
• Electric circuit boards components layout
• Exploded diagram
• Electrical circuit boards schematics

Revision Status
Revision Issued Date Description
A Januar
y
06, 1999 First Release
B Februar
y
15, 1999
The followin
g
items have been revised:
<Chapter 4>
•Pa
g
e 105/Table 4-1:
Some contents have been chan
g
ed.
•Fi
g
ure 4-4, Fi
g
ure 4-17:
Contents of the fi
g
ures have been corrected.
•Fi
g
ure 4-13, 4-15, 4-16, 4-24, 4-25, 4-39, 4-40, 4-41:
Fi
g
ure titles have been corrected.
•Fi
g
ure 4-14:
Fi
g
ure title and the contents of the fi
g
ure have been corrected.
<Chapter 5>
Pa
g
es from 140 throu
g
h 145:
Head An
g
ular Adjustment procedure has been chan
g
ed due to overall
review of the section.
C March 4, 1999
The whole book is revised. The actual chan
g
e is made on the followin
g
points:
• Chapter 4 / Pa
g
e 115 / Fi
g
ure 4-18 and step 3
• Chapter 5 / Pa
g
e 135 to 141and Pa
g
e 148.
The rest of the pa
g
es in this chapter onl
y
chan
g
ed in pa
g
e numbers.
• Chapter 6 and 7 chan
g
ed in pa
g
e numbers onl
y
.

Contents
Product Description
Features ...................................................................................................... 10
Specifications ............................................................................................ 11
Printing Specifications ............................................................................ 11
Options and Consumable Products ........................................................ 14
Paper Specifications ............................................................................... 15
Cut Sheet ........................................................................................... 15
Transparency, Glossy Paper .............................................................. 15
Envelope ............................................................................................ 15
Index Card .......................................................................................... 15
Self Adhesive Sheets ......................................................................... 15
Photo Paper ....................................................................................... 16
Photo Stickers .................................................................................... 16
Printable Area ......................................................................................... 17
Ink Cartridge Specifications .................................................................... 19
Black Ink Cartridge ............................................................................. 19
Color Ink Cartridge ............................................................................. 20
Electrical Specifications .......................................................................... 21
Environmental Condition ........................................................................ 21
Reliability ................................................................................................ 22
Safety Approvals .................................................................................... 22
Acoustic Noise ........................................................................................ 22
CE Marking (220 ~ 240 V version) ......................................................... 22
Physical Specifications ........................................................................... 22
Interface ...................................................................................................... 23
Parallel Interface (Forward Channel) ..................................................... 23
Parallel Interface (Reverse Channel) ..................................................... 26
Mac Serial Interface ............................................................................... 28
USB Interface ......................................................................................... 29
Printer Language and Emulation ............................................................ 29
Prevention Hosts from Data Transfer time-out ....................................... 29
Auto Interface Selection ......................................................................... 29
IEEE 1284.4 Protocol ......................................................................... 30
Control Panel Operation ........................................................................... 31
Indicators (LEDs) ................................................................................... 31
Panel Functions ..................................................................................... 32
Printer Setting Mode ........................................................................... 32
Special Setting Mode ......................................................................... 34
Printer Condition and Panel Status ........................................................ 35
Error Status ................................................................................................ 36
Ink Out .................................................................................................... 36
Paper Out ............................................................................................... 36
Paper Jam .............................................................................................. 36
No Ink Cartridge ..................................................................................... 36
Maintenance Request ............................................................................ 36
Fatal Errors ............................................................................................ 36
Printer Initialization ................................................................................... 37
Component Layout .................................................................................... 38
Printer Mechanism ................................................................................. 38
C265 Main Board ................................................................................... 39
C265 PSB/PSE Board ............................................................................ 41
C265 PNL Board .................................................................................... 42
C265 Relay Board .................................................................................. 42
Operating Principles
Overview .................................................................................................... 44
Printer Mechanism Operating Principles ................................................ 44
Carriage Mechanism .............................................................................. 46
Printing Mechanism ................................................................................ 48
Paper Load Mechanism ......................................................................... 49
Paper Feed Mechanism ......................................................................... 51
Pump/ASF Switch Mechanism ............................................................... 52
Pump / Carriage Lock / Head Cleaner Mechanism ................................ 54

Electrical Circuit Operation Principles .................................................... 56
C265 PSB/PSE Power Supply Board ..................................................... 56
C265Main Board .................................................................................... 59
CR Motor Driver Circuit .......................................................................... 67
PF Motor Driver Circuit ........................................................................... 69
Pump/ASF Motor Driver Circuit .............................................................. 71
Printhead Driver Circuit .......................................................................... 72
Cooling Fan Driver Circuit ...................................................................... 74
ASF Solenoid Driver Circuit .................................................................... 76
EEPROM Control Driver Circuit ............................................................. 77
Troubleshooting
Overview ..................................................................................................... 79
Troubleshooting with LED Error Indications ........................................... 80
Remedies for Paper Out Error ............................................................ 81
Remedies for the Paper Jam Error ..................................................... 83
Remedies for No I/C and Ink Out Errors ............................................. 85
Remedies for the Maintenance Error ................................................. 87
Remedies for Fatal Error .................................................................... 88
Isolating the Faulty Part on the Power Supply Board ............................. 90
Isolating the Faulty Part according to the Phenomenon ......................... 92
Disassembly and Assembly
Overview ................................................................................................... 102
Precautions for Disassembling the Printer ........................................... 102
Disassembly Procedures ........................................................................ 104
Upper Case and Control Panel Removal ............................................. 106
Printer Mechanism Removal ................................................................ 107
C265 Main Board Unit Removal ........................................................... 108
Relay Board and Cooling Fan Removal ............................................... 109
Shield Plate on the C265 Main Board Removal ................................... 110
C265 PSB/PSE Board Removal ........................................................... 111
Printer Mechanism Disassembly .......................................................... 112
Printhead Removal ........................................................................... 112
CR Motor Removal ........................................................................... 114
PF Motor Removal ........................................................................... 115
Pump/ASF Motor and Solenoid Removal ......................................... 116
ASF Unit Removal ............................................................................ 116
ASF Sensor Removal ....................................................................... 121
CRHP Sensor Removal .................................................................... 122
PE Sensor Removal ......................................................................... 122
Encoder Belt Sensor Removal ......................................................... 123
Carriage Unit Removal ..................................................................... 124
Pump Unit Removal ......................................................................... 125
Paper Eject Frame Removal ............................................................ 126
Paper Eject Roller Removal ............................................................. 126
Platen Removal ................................................................................ 127
PF Roller Removal ........................................................................... 128
Adjustment
Overview .................................................................................................. 131
Conditions for Each Adjustment ........................................................... 131
Adjustments ............................................................................................. 134
Preliminary Operation .......................................................................... 134
Market Destination Check .................................................................... 136
Head Actuator Voltage Input ................................................................ 137
Head Angular Adjustment .................................................................... 141
Bi-Directional Adjustment ..................................................................... 148
Printhead Cleaning Using the Program ................................................ 153
Initial Ink Charge .................................................................................. 154
Indication of the Counter Value for the Waste Ink Pad ........................ 155
Fan Check ............................................................................................ 157
Paper Gap Adjustment ......................................................................... 158
Maintenance
Overview .................................................................................................. 162
Maintenance ......................................................................................... 162
Cleaning the Printhead ..................................................................... 163
Maintenance Request Error ............................................................. 164
Lubrication and Adhesion ...................................................................... 165
Lubricating the Carriage Guide Shaft ................................................... 166
Appendix
Connector Summary ............................................................................... 172
EEPROM ADDRESS MAP ....................................................................... 176
Component Layout .................................................................................. 180
Parts List .................................................................................................. 184
Exploded Diagrams ................................................................................. 187
Circuit Diagrams ...................................................................................... 195

PRODUCT DESCRIPTION

EPSON Stylus Color 900 Revision C
Product Description Features 10
1.1 FEATURES
The Stylus COLOR 900 is the latest in EPSON’s advanced lines of ink
jet printers and offering the following features.
High color print quality:
- 1440 (H) x720 (V) dpi printing
- Printing with 4 color inks (YMCK)
- Traditional and New Microweave
- Imprevement in color rendering using variable dot
Built-in auto sheet feeder:
- Holds 100 cut-sheets (64 g/m2)
- Holds 10 envelopes
- Holds 30 transparency fIlms
Built-in 3 I/F and 1 optional I/F card slot
- Mac serial I/F (up to approximately 1.8 Mbps)
- Bi-directional parallel I/F (lEEE-1284 level 1 device)
- USB
- Optional Type-B level 2 I/F card slot
4 scaleable fonts, 5 LQ fonts
13 character tables (Standard version)
37 character tables (NLSP version)
Figure 1-1. Stylus Color 900

EPSON Stylus Color 900 Revision C
Product Description Specifications 11
1.2 Specifications
1.2.1 Printing Specifications
Print method: On demand ink jet
Nozzle configuration: Monochrome=192 nozzles (96 x 2 staggered)
Color=96 nozzles x 3 (Cyan, Magenta,
Yellow)
(See Figure 1-2 for the nozzle configuration.)
Figure 1-2. Nozzle configuration
Print direction: Bi-direction with logic seeking
Print speed and Printable columns
Control code: ESC/P2 and expanded raster graphics code
EPSON Remote command
IBM X24E emulation
360 dpi
180 dpi
#1
#96 #96
#95
#94
#93
#2
#3
#95
#94
#93
#96
#95
#94
#93
#1
#2
#3
#1
#2
#3
#96
#95
#94
#93
#1
#2
#3
R ow A (B lack 1)
R ow B (B lack 2)
R ow C (M agenta)
Row D (Cyan)
Row E (Yellow)
Table 1-1.
Print Speed and Printable Columns for Character Mode
Character pitch Printable columns LQ speed
10 CPI (Pica) 80 285 CPS
12 CPI (Elite) 96 342 CPS
15 CPI 120 428 CPS
17 CPI (Pica condensed) 137 487 CPS
20 CPI (EIite condensed) 160 570 CPS
Table 1-2.
Print Speed and Printable columns for Raster Graphics Mode
Horizontal
resolution Printable area Available dot CRS
180 dpi 8.26 inch 1488 28.5 IPS
360 dpi 8.26 inch 2976 28.5 IPS
720 dpi 8.26 inch 5952 20 IPS

EPSON Stylus Color 900 Revision C
Product Description Specifications 12
Character tables: Legal and 14 international character sets
Standard version: (13 character tables)
Italic table PC 860 (Portuguese)
PC 850 (Multilingual) PC 437(US, Standard Europe)
PC 861 (Icelandic) PC 863(Canadian-French)
PC 865(Nordic) Abicomp
BRASCII Roman 8
ISO Latin 1 PC 858
ISO 8859-15
NLSP version: (36 character tables)
Italic table PC437 PC437 Greek
PC850 PC852 PC853
PC855 PC857 PC860
PC861 PC865 PC866
PC869 MAZOWIA Code MJK
ISO 8859-7 lSO Latin 1T Bulgaria
PC774 Estonia ISO 8859-2
PC866 LAT PC866 UKR PC AR864
PC APTEC PC708 PC720
Hebrew7* Hebrew8* PC862*
Abicomp BRASCII Roman 8
ISO Latin 1 PC 858 lSO 8859-15
* These character tables can not be selected in the Default setting
mode.
Typeface
Bit map LQ font:
EPSON Roman 10 CPI, 12 CPI, 15CPI, Proportional
EPSON Sans Serif 10 CPI, 12 CPI, 15CPI, Proportional
EPSON Courier 10 CPI, 12 CPI, 15CPI
EPSON Prestige 10 CPI, 12 CPI, 15CPI
EPSON Script 10 CPI, 12 CPI, 15CPI
Scaleable font
EPSON Roman 10.5 pt., 8 pt., - 32 pt. (every 2 pt.)
EPSON Sans Serif 10.5 pt., 8 pt., - 32 pt. (every 2 pt.)
EPSON Roman T 10.5 pt., 8 pt., - 32 pt. (every 2 pt.)
EPSON Sans Serif H 10.5 pt., 8 pt., - 32 pt. (every 2 pt.)
* Each Typeface has 4 variations as the following example of
EPSON Roman.
EPSON Roman normal
EPSON Roman bold
EPSON Roman italic
EPSON Roman bold italic
See Table 1-3 which lists the character tables and available
typefaces.
Feeding method: Friction feed with ASF
Line spacing: 1/6 inch, 1/8 inch or programable at 1/360
inch
Paper path: Cut-sheet ASF (Top entry, Front out)
Feed speed: 192/360 inch feed = 116 ms
Continuous feed = 176.3 mm/second
(6.94 inch/second)
Input data buffer: 256 KB

EPSON Stylus Color 900 Revision C
Product Description Specifications 13
* Not mentioned in the User’s Guide. These character tables can not select in the default setting
mode.
Table 1-3. Character Tables and Available Typefaces
Character Tables Bit map font Scaleable font
Standard version
Italic table
PC 860 (Portuguese)
PC 861 (Icelandic)
PC 865 (Nordic)
Abicomp
lSO Latin1
ISO 8859-15
PC 437 (US Standard Europe)
PC 850 (Multilingual)
PC 863 (Canadian-French)
BRASCII
Roman 8
PC 858
EPSON Roman
EPSON Sans Serif
EPSON Courier
EPSON Prestige
EPSON Script
EPSON Roman
EPSON Sans Serif
EPSON Roman T
EPSON Sans Serif H
NLSP version
Italic table
PC 850 (Multilingual)
PC 861 (Icelandic)
Abicomp
lSOLatin1
ISO 8859-15
PC 437(US Standard Europe)
PC 860(Portuguese)
PC 865(Nordic)BRASCIl
Roman8
PC 858
PC437Greek
PC 853 (Turkish)
PC 857 (Turkish)
PC 869 (Greek)
Code MJK (CSFR)
lSO Latin 1T (Turkish)
PC7 74
1SO 8859-2 (lSO Latin 2)
PC 866 UKR
PC 852 (East Europe)
PC 855 (Cyrillic)
PC 866 (Russian)
MAZOWIA (Poland)
lSO 8859-7 (Latin/Greek)
Bulgaria (Bulgarian)
Estonia
PC 866 LAT
EPSON Roman
EPSON Sans Serif
EPSON Courier
EPSON Prestige
EPSON Script
EPSON Roman
EPSON Sans Serif
PC APTEC (Arabic)
PC 720 (Arabic) PC 708 (Arabic)
PC AR864 (Arabic)
EPSON Roman
EPSON Sans Serif Not supported
Hebrew7*
Hebrew 8*
PC862 (Hebrew)*
EPSON Roman
EPSON Courier Not supported

EPSON Stylus Color 900 Revision C
Product Description Specifications 14
1.2.2 Options and Consumable Products
NOTE: The asterisk (
∗
) is a substitute for the last digit of the product
number, which varies by country.
NOTE: The availability of special media varies by country.
Table 1-4. Options Available for Stylus Color 900
Table 1-5. Ink Cartridge Available for Stylus Color 900
Table 1-6. EPSON Special Media
Items Codes
32KB Serial I/F card C82307∗ / C82308∗
32KB Parallel Interface Card C80310∗
Coax I/F card C82314∗
Twin-ax I/F card C82315∗
LocalTalk Interface Card C82312∗
Type B Ethernet Interface Card C82362∗/ C82363∗ /
C82364∗
Type B Bi-directional Parallel Interface Card C82345∗
Parallel Interface Cable (shielded) from D-SUB 25-pin
(computer) to 36-pin Amphenol 57 Series (printer) C83602∗
Serial Interface Cable from D-SUB 25-pin (computer)
to D-SUB 25-pin (printer) C83603∗ / C83604∗
Serial Interface Cable from D-SUB 9-pin (computer)
to D-SUB 25-pin (printer) C83605∗ / C83606∗
USB Interface Cable (shielded) from Series A 4-pin
(computer) to Series B 4-pin (printer) (This cable is
not supplied in all locations.) C83623∗
Items Codes
Black Ink Cartridge T003
Color Ink Cartridge T005
Items Codes
EPSON 360 dpi Ink Jet Paper (A4) S041059 / S041025
EPSON 360 dpi Ink Jet Paper (Letter) S041060 / S041028
EPSON Photo Quality Ink Jet Paper (A4) S041061 / S041026
EPSON Photo Quality Ink Jet Paper (Letter) S041062 / S041029
EPSON Photo Quality Ink Jet Paper (Legal) S041067 / S041048
EPSON Photo Quality Ink Jet Card (A6) S041054
EPSON Photo Quality Ink Jet Card (5 x 8”) S041121
EPSON Photo Quality Ink Jet Card (8 x 10”) S041122
EPSON Photo Quality Self Adhesive Sheet (A4) S041106
EPSON Ink Jet Note Card (A6) (with envelopes) S041147
EPSON Ink Jet Greeting Cards (5 x 8”) (with envelops) S041148
EPSON Ink Jet Greeting Cards (8 x 10”) (with envelops) S041149
EPSON Photo Quality Glossy Film (A4) S041071
EPSON Photo Quality Glossy Film (Letter) S041172
EPSON Photo Quality Glossy Film (A6) S041107
EPSON Ink Jet Transparencies (A4) S041063
EPSON Ink Jet Transparencies (Letter) S041064
EPSON Photo Paper (A4) S041140
EPSON Photo Paper (Letter) S041141
EPSON Photo Paper (4 x 6”) S041134
EPSON Photo Paper Cards (A4) S041177
EPSON Photo Stickers 16 (A6) S041144
EPSON Photo Stickers 4 (A6) S041176
EPSON Panoramic Photo Paper (210 x 594 mm) S041145
EPSON Iron-On Cool Peel Transfer Paper (A4) S041154
EPSON Iron-On Cool Peel Transfer Paper (Letter) S041153 / S041155

EPSON Stylus Color 900 Revision C
Product Description Specifications 15
1.2.3 Paper Specifications
This section describes paper specifications including paper handling
and printable area.
Paper Handling: Do not feed paper in reverse more than 9.5 mm
(0.38”).
1.2.3.1 Cut Sheet
Size:
A4: [Width 210 mm (8.3”) x Length 297 mm (11.7”)]
A5: [Width 148 mm (5.8”) x Length 210 mm (8.3”)]
Letter: [Width 216 mm (8.5”) x Length 279 mm (11.0”)]
B5: [Width 182 mm (7.2”) x Length 257 mm (10.1”)]
Legal: [Width 216 mm (8.5”) x Length 356 mm (14.0”)]
Half Letter: [Width 139.7 mm (5.5”) x Length 215.9 mm (8.5”)]
Executive: [Width 184.2 mm (7.25”) x Length 266.7mm(10.5”)]
Thickness: 0.08 mm (0.003”) - 0.11 mm (0.004”)
Weight: 64g/m2 (17Ib.) - 90g/m2 (24Ib.)
Paper Types: Bond paper, Plain paper, EPSON special media
1.2.3.2 Transparency, Glossy Paper
Size
A4: [Width 210 mm (8.3”) x Length 297 mm (11.7”)]
Letter: [Width 216 mm (8.5”) x Length 279 mm (11.0”)]
A6: [Width 105 mm (4.1”) x Length 148 mm (5.8”)]
Thickness: 0.075 mm (0.003”) - 0.085 mm (0.0033”)
Paper Types: EPSON special media
NOTE: Print on transparency at normal temperatures only.
1.2.3.3 Envelope
Thickness: 0.08 mm (0.003”) - 0.11 mm (0.004”)
Size:
No.10: [Width 241 mm (9 1/2”) x Length 104.8 mm (4 1/8”)]
DL: [Width 220 mm (8.7”) x Length 110 mm (4.3”)]
C6: [Width 162 mm (6.4”) x Length 114 mm (4.5”)]
5 x 8”: [Width 220 mm (8.7”) x Length 132 mm (5.2”)]
Thickness: 0.16 mm (0.006”) - 0.52 mm (0.02”)
Weight: 45g/m2 (12Ib.) - 75g/m2 (20Ib.)
Quality: Bond paper, Plain paper, Airmail
NOTES:
1. Print on envelope at normal temperatures only.
2. Place the longer side of the envelope horizontal.
1.2.3.4 Index Card
Size:
A6 Index card: [Width 105 mm (4.1”) x Length 148 mm (5.8”)]
5 x 8” Index card: [Width 127 mm (5.0”) x Length 203 mm (8.0”)]
10 x 8” Index card:[Width 127 mm (5.0”) x Length 203 mm (8.0”)]
Thickness:Less than 0.23 mm (0.0091”)
Paper Types: EPSON special media
1.2.3.5 Self Adhesive Sheets
Size
A4: [Width 210 mm (8.3”) x Length 297 mm (11.7”)]
Paper Types: EPSON special media

EPSON Stylus Color 900 Revision C
Product Description Specifications 16
1.2.3.6 Photo Paper
Size:
A4: [Width 210 mm (8.3”) x Length 297 mm (11.7”)]
Letter: [Width 216 mm (8.5”) x Length 279 mm (11.0”)]
4 x 6”: [Width 102 mm (4”) x Length 152 mm (6”)]
Panoramic: [Width 210 mm (8.3”) x Length 594 mm (23.4”)]
Paper Types: EPSON special media
1.2.3.7 Photo Stickers
Size:
A6 with 4 or 16 frames:
[Width 105 mm (4.1”) x Length 148 mm (5.8”)]
Paper Types: EPSON special media

EPSON Stylus Color 900 Revision C
Product Description Specifications 17
1.2.4 Printable Area
Cut Sheet
See Figure 1-3 and Table 1-7 for the printable area for cut sheets.
Figure 1-3. Printable Area for Cut Sheets
Table 1-7.
Minimum margin for Raster Graphics Mode / Character Mode
*1: For Raster Graphics mode
*2: For Character mode
*3: The minimum bottom margin is reduced to 3 mm when paper dimension is defined
by using the command. Otherwise, the minimum bottom margin remains 14 mm.
Note the extra printing area with the bottom margin of 3 mm is not a guaranteed
area.
Printable area
BM
PL
TM
RM
PW
LM
L M : L e ft M a rg in e
RM: Right Margine
TM : Top M argine
B M : B o tto m M a rg in e
PW : P aper W idth
PL: Paper Length
Paper
Size Left Margin
(Minimum) Right Margin
(Minimum) Top Margin
(Minimum) Bottom Margin
(Minimum)
A4 3 mm (0.12”) 3 mm (0.12”) 3 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3
A5 3 mm (0.12”) 3 mm (0.12”) 3 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3
Letter 3 mm (0.12”) 3 mm (0.12”)*1
9 mm (0.35”)*23 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3
B5 3 mm (0.12”) 3 mm (0.12”) 3 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3
Legal 3 mm (0.12”) 3 mm (0.12”)*1
9 mm (0.35”)*23 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3
Half Letter 3 mm (0.12”) 3 mm (0.12”) 3 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3
Executive 3 mm (0.12”) 3 mm (0.12”) 3 mm (0.12”) 14 mm (0.54”)
3 mm (0.12”) *3

EPSON Stylus Color 900 Revision C
Product Description Specifications 18
EnvelopeSee Table 1-8 and Figure 1-4 which show the minimum
margin and printable area for envelopes, respectively.
Table 1-8. Minimum Margin for Envelopes
Figure 1-4. Printable Area for Envelopes
Paper
Size Left Margin
(Minimum) Right Margin
(Minimum) Top Margin
(Minimum) Bottom Margin
(Minimum)
#10 3 mm (0.12”) 28 mm (1.10”) 3 mm (0.12”) 14 mm (0.54”)
DL 3 mm (0.12”) 7 mm (0.28”) 3 mm (0.12”) 14 mm (0.54”)
C6 3 mm (0.12”) 3 mm (0.12”) 3 mm (0.12”) 14 mm (0.54”)
5 x 8 3 mm (0.12”) 7 mm (0.28”) 3 mm (0.12”) 14 mm (0.54”)
RMLM
Printable
A re a BM
TM

EPSON Stylus Color 900 Revision C
Product Description Specifications 19
1.2.5 Ink Cartridge Specifications
1.2.5.1 Black Ink Cartridge
Type: Exclusive ink cartridge
Color: Black
Print Capacity: 1200 pages / A4 (ISO/IEC 10561 Letter
Pattern at 360 dpi)
Ink life: 2 years from indicated production date
Storage temperature:
Storage: -20°C ~ 40°C(within a month at 40 °C)
Packing storage: -30°C ~ 40°C(within a month at 40 °C)
Transit: -30°C ~ 60°C(within 120 hours at 60°C and
within a month at 40°C)
Dimensions: 28.9 mm (W) x 67.4 mm (D) x 41.8 mm (H)
Figure 1-5. Black Ink Cartridge Appearance
28.9 m m
65.9 m m (R ib area)
41.8 m m
27.4 m m (R ib area)
67.4 m m

EPSON Stylus Color 900 Revision C
Product Description Specifications 20
1.2.5.2 Color Ink Cartridge
Type: Exclusive ink cartridge
Color: Magenta, Cyan, Yellow
Print Capacity: 530 pages / A4 (at 360 dpi, 5 X duty each
color)
Ink life: 2 years from indicated production date
Storage temperature:
Storage: -20°C ~ 40°C(within a month at 40 °C)
Packing storage: -30°C ~ 40°C (within a month at 40 °C)
Transit: -30°C ~ 60°C (within 120 hours at 60°C and
within a month at 40°C)
Dimensions: 54.0 mm (W) x 67.4 mm (D) x 41.8 mm (H)
NOTES
1. Do not refill the cartridge. It is a consumable item.
2. Do not used the ink cartridge whose ink life has expired.
3.
Ink will be frozen below -4 °C. To use ink that is frozen, let it defrost
for at least 3 hours at room temperature.
Figure 1-6. Color Ink Cartridge
54 m m
67.4 m m
41.8 m m
65.9 m m (R ib area)
52.5 m m (R ib area)

EPSON Stylus Color 900 Revision C
Product Description Specifications 21
1.2.6 Electrical Specifications
[120V version]
Rated voltage: AC120V
Input voltage range: AC99 ∼132V
Rated frequency range: 50 ∼ 60 Hz
Input frequency range: 49.5 ∼ 60.5 Hz
Rated current: 0.4A (Maximum 0.5A)
Power consumption: Approx.18W (ISO/IEC 10561 Letter pattern)
Energy Star compliant
Insulation Resistance: 10 M ohms min.
(between AC line and chassis, DC 500 V)
Dielectric strength: AC1000 V rms. 1 minute or AC1200 Vrms.
1 second (between AC line and chassis)
[220∼240V version]
Rated voltage: AC220V ∼ 240V
Input voltage range: AC198 ∼ 264V
Rated frequency range: 50 ∼ 60Hz
Input frequency range: 49.5 ∼ 60.5Hz
Rated current: 0.2 A (Maximum 0.3A)
Power consumption: Approx.18W (ISO/IEC 10561 Letter pattern)
Energy Star compliant
Insulation Resistance: 10M ohms min.
(between AC line and chassis, DC500V)
Dielectric strength: AC1500 V rms.
1 minute (between AC line and chassis)
1.2.7 Environmental Condition
Temperature: Operating = 10 to 35 °C (See Figure 1-7.)
Non-operating = -20 to 60 °C *2
1 month at 40 °C
120 hours at 60 °C
Humidity: Operating = 20% ~ 80% RH *2
(See Figure 1-7.)
Non-operating = 5% ~ 85% RH *1 *2
Figure 1-7. Temperature / Humidity of Range
Resistance to shock: Operating = 1G, within 1 ms
Non-operating = 2G, within 2 ms *1
Resistance to vibration: Operating = 0.15G (Operating)
Non-operating = 0.50G *1
*1: With a shipment container
*2: Without condensation
Hum idity
(% R H )
80%
55%
20%
10 27 35
50 ( C )
80 95 ( F )
G uaranteed
A re a

EPSON Stylus Color 900 Revision C
Product Description Specifications 22
1.2.8 Reliability
Total print volume: 75,000 pages (A4, Letter)
Printhead life: 4000 million dots/nozzle
1.2.9 Safety Approvals
[120V version]
Safety standard: UL1950
CSA22.2 No.950
EMI: FCC part 15 subpart B class B
CSA C108.8 class B
[220∼240V version]
Safety standard: EN 60950 (VDE)
EMI: EN55022 (CISPR Pub.22) class B
AS/NZS 3548 class B
1.2.10 Acoustic Noise
Level: Approximately 47 dB (A) (According to ISO
7779)
1.2.11 CE Marking (220 ∼ 240 V version)
Low Voltage Directive 73/23/EEC: EN60950
EMC Directive 89/336/EEC: EN55022 Class B
EN61000-3-2
EN61000-3-3
EN50082-1
IEC801-2
IEC801-3
IEC801-4
1.2.12 Physical Specifications
Weight: 8.4 Kg
Dimensions: 647 mm (W) x 296 mm (D) x 325 mm (H)

EPSON Stylus Color 900 Revision C
Product Description Interface 23
1.3 Interface
The EPSON Stylus Color 900 is equipped with USB, bi-directional 8-bit
parallel interface, serial interface and a card slot for an optional Type-B
interface.
1.3.1 Parallel Interface (Forward Channel)
Transmission mode: 8 bit parallel, IEEE-1284 compatibility mode
Synchronization: By /STROBE pulse
Handshaking: BY BUSY and /ACKLG signal
Signal level: TTL compatible level
Adaptable connector: 57-30360 (amphenol) or equivalent
The BUSY signal is set high before setting either/ERROR low or PE
high, and held high until all these signals return to an inactive state.
The BUSY signal is HIGH:
During data entry (see Data transmission timing)
When the input data buffer is full
While /INIT signal is at LOW level or during hardware
initialization.
During a printer error condition (See /ERROR signal).
When the parallel interface is not selected.
The /ERROR signal is LOW when one of the following error has
occurred:
Printer hardware error (fatal error)
Paper Out error
Paper Jam error
Ink Out error
The PE signal is at a high level during Paper Out error.
See Figure 1-8 and Table 1-9 which show the data transmission timing.
Figure 1-8. Data Transmission Timing
DATA
-
STRO BE
BUSY
-ACKNLG
data byte n data byte n+1
thold
tsetup
ts tb tnext
tready tbusy
treply ta c k tnbusy

EPSON Stylus Color 900 Revision C
Product Description Interface 24
NOTE: tt-out shows the rise and fall time of every output signal.
tt-in shows the rise and fall time of every input signal.
Typical time of tack is shown in Table 1-10.
Table 1-10. Typical Time of Tack
Table 1-11. Signal level for TTL Compatible
(IEEE-1284 level 1 device)
* A LOW logic level on the Logic H signal is as follows:
2.0 V or less when the printer is turned off.
3.0 V or more when the printer is turned on.
The receiver provides an impedance equivalent to 7.5 K
Ω
to
ground.
See Table 1-12 which shows the connector pin assignment and signals
for the forward channel of the parallel interface.
Table 1-9. Data Transmission Timing
Parameter Minimum Maximum
tsetup 500ns ---
thold 500ns ---
tstb 500ns ---
tready 0 ---
tbusy --- 500ns
tt-out* --- 120ns
tt-in** --- 200ns
treply 0 ---
tack 500ns 10us
tnbusy 0 ---
tnext 0 ---
Parallel Interface Mode Typical Time of Tack
High speed 1 us
Normal speed 3 us
Parameters Minimum Maximum COndition
VOH* --- 5.5V
VOL* -0.5V ---
IOH* --- 0.32mA VOH = 2.4V
IOL --- 12mA VOL = 0.4V
CO --- 50pF
VIH --- 2.0V
VIL 0.8V ---
IIH --- 0.32mA VIH = 2.0V
IIL --- 12mA VIL = 0.8V
CI --- 50pF

EPSON Stylus Color 900 Revision C
Product Description Interface 25
*: In and Out refers to the direction of the signal as viewed from the printer.
Table 1-12. Parallel I/F Forward Channel
Pin No. Signal Name Return
GND Pin In/Out Functional Description
1 /STROBE 19 I The strobe pulse. Read-in of data is performed at the falling edge of this pulse.
2DATA0 20 I
The DATA0 through DATA7 signals represent data bits 0 to 7, respectively. Each
signal is at high level when data is logical 1 and low level when data is logical 0.
3DATA1 21
4DATA2 22
5DATA3 23
6DATA4 24
7DATA5 25
8DATA6 26
9DATA7 27
10 /ACKNLG 28 O This signal is a negative pulse indicating that the printer can again accept data.
11 BUSY 29 O A high signal indicates that the printer cannot receive data.
12 PE 28 O A high signal indicates paper-out error.
13 SLCT 28 O Always at high level when the printer is powered on.
14 /AFXT 30 I Not used.
31 /INIT 30 I The falling edge of a negative pulse or a low signal on this line causes the printer to
initialize. Minimum 50 us pulse is necessary.
32 /ERROR 29 O A low signal indicates printer error condition.
36 /SLIN 30 I Not used.
18 Logic H ---- O Pulled up to +5V via 3.9K ohm resistor.
35 +5V ---- O Pulled up to +5V via 3.9K ohm resistor.
17 Chassis GND ---- --- Chassis GND.
16,33,
19-30 GND ---- --- Signal GND.
15,34 NC ---- --- Not connected.

EPSON Stylus Color 900 Revision C
Product Description Interface 26
1.3.2 Parallel Interface (Reverse Channel)
Transmission mode: IEEE-1284 nibble mode
Adaptable connector: See the forward channel.
Synchronization: Refer to the IEEE-1284 specification
Handshaking: Refer to the IEEE-1284 specification
Data trans. timing: Refer to the IEEE-1284 specification
Signal level: IEEE-1284 level 1 device
(See forward channel.)
Extensibility request:
The printer responds affirmatively when the extensibility request
values are 00H or 04H,as follows;
00H:Request Nibble Mode Reverse Channel Transfer.
04H:Request device ID using Nibble Mode Rev Channel
Transfer.
Device ID:
The printer sends following device ID string upon request.
When IEEE1284.4 is enabled;
[00H] [60H]
MFG:EPSON;
CMD:ESCPL2,PRPXL,BDC,D4;
MDL:Stylus[SP]COLOR[SP]900;
CLS:PRINTER;
DES:EPSON[SP]Stylus[SP]COLOR[SP]900;
When IEEE1284.4 is disabled;
[00H] [5DH]
MFG:EPSON;
CMD:ESCPL2,PRPXL,BDC;
MDL:Stylus[SP]COLOR[SP[900;
CLS:PRINTER;
DES:EPSON[SP]Stylus[SP]COLOR[SP]900;
NOTES:
1. [00H] denotes a hexadecimal value of zero.
2. MDL value and DES value depend on the EEPROM setting.
3. CMD value depends on the IEEE1284.4 setting.
See Table 1-13 which shows pin assignment for reverse channel

EPSON Stylus Color 900 Revision C
Product Description Interface 27
Table 1-13. Pin Assignment For Reverse Channel
Pin No. Signal Name Return GND
Pin In/Out Functional Description
1 HostClk 19 I Host clock signal.
2-9 Data0-7 20-27 I
The DATA0 through DATA7 signals represent data bits 0 to7,
respectively. Each signal is at high level when data is logical 1 and
low level when data is logical 0. These signals are used to transfer
the 1284 extensibility request values to the printer.
10 PrtClk 28 O Printer clock signal.
11 PtrBusy, Data Bit-3,7 29 O Printer busy signal and reverse channel transfer data bit 3 or 7.
12 AckData Req, DataBit-2,6 28 O Acknowledge data request signal and reverse channel transfer
data bit 2 or 6.
13 Xflag, DataBit-1,5 28 O X-flag signal and reverse channel transfer data bit 1 or 5.
14 HostBusy 30 I Host busy signal.
31 /INIT 30 I Not used.
32 /DataAvail, DataBit-0,4 29 O Data available signal and reverse channel transfer data bit 0 or 4.
36 1284-Active 30 I 1284 Active Signal
18 Logic-H ---- O Pulled up to +5V via 3.9K ohm resister.
35 +5V ---- O Pulled up to +5V via 3.3K ohm resister.
17 Chassis GND ---- --- Chassis GND.
16,33, 9-30 GND ---- --- Signal GND.
15,34 NC ---- --- Not connected.
* In/Out refers to the direction of signal flow from the printer’s point of view.

EPSON Stylus Color 900 Revision C
Product Description Interface 28
1.3.3 Mac Serial Interface
Standard: Based on RS-423
Synchronization: Synchronous
Bit Rate: Approximately 1.8 Mbps
Handshaking: X-ON/X-OFF, DTR Protocol
Word Format: Start Bit = 1 bit
Data Bit = 8 bit
Parity Bit = No parity bit
Stop Bit = 1 bit
Adaptable Connector: 8-pin mini circular connector
Recommended Cable:Apple System Peripheral-8 Cable
Connector pin assignment and signal:See Table 1-14.
Table 1-14. Pin Assignment
X-ON/X-OFF, DTR protocol:See Table 1-15.
Table 1-15. X-On/X-Off and DTR Protocol
Pin No. Signal
Name I/O Description
1 SCLK O Synchronous clock signal
2CTS I Clear To Send
3 TXD- O Transmit Data (-)
4SG I (Signal Ground)
5 RXD- I Receive Data (-)
6TXD+ O Balanced Transmit Data (+)
7 DTR O Data Terminal Ready
8RXD+ I Balanced Receive Data (+)
State Buffer Space X-ON/X-OFF DTR
Busy Less than 3072 bytes Send X-OFF code OFF
Ready More than 5120 bytes Send X-ON code ON

EPSON Stylus Color 900 Revision C
Product Description Interface 29
1.3.4 USB Interface
Standard: Based on the following:
Universal Serial Bus Specifications Rev. 1.0
Universal Serial Bus Device Class Definition
for Printing Device Version 1.0
Bit Rate: 12 M bps
Data Encoding: NRZI
Adaptable Connector: USB Series B
Recommended Cable Length:2 meters
Table 1-16. Pin Assignment and Signal of the USB I/F
Figure 1-9. USB Pin Assignment
1.3.5 Printer Language and Emulation
Printer language: ESC/P2
IBM X24E emulation
EPSON Remote
1.3.6 Prevention Hosts from Data Transfer time-out
Generally, hosts abandon data transfer to peripherals when a peripheral
is in the busy state for dozens of seconds continuously. To prevent
hosts from this kind of time-out, the printer receives data very slowly,
several bytes per minute, even if the printer is in busy state. This
showdown is started when the rest of the input buffer becomes several
hundreds of bytes. Finally, the printer is in the busy state continuously
when the input buffer is full.
1.3.7 Auto Interface Selection
The EPSON Stylus Color 900 has four types of interfaces: USB, parallel
interface, Mac serial interface and optional Type-B interface. Each
interface can be selected manually in default setting mode or
automatically.
Manual Selection:
One of four interfaces can be selected in default setting mode.
Automatic Selection:
The automatic interface selection is enabled by the default setting
mode. In this automatic interface selection mode, the printer is
initialized to the idle state scanning for which interface is to receive
data when it is powered on. The interface that receives data first is
selected. When the host stops data transfer and the printer is in the
stand-by state for a number of seconds, the printer returns to the
idle state. As long as the host sends data or the printer interface is
busy state, the selected interface is let as it is.
Pin No. Signal
Name I/O Description
1 Vcc ---- Cable power, Maxi. power consumption
is 100 mA
2-Data Bi-D Data
3 +Data Bi-D Data, pull up to +3.3 V via 1.5 K ohms
resistor
4Ground ---- Cable Ground
Pin #1
Pin #2
Pin #3 Pin #4

EPSON Stylus Color 900 Revision C
Product Description Interface 30
Interface state and interface selection
When an interface other than parallel interface is selected, the
parallel interface goes into the BUSY state.
When an interface other than serial interface is selected, the
serial interface sets the DTR signal to MARK.
When an interface other than optional interface is selected, the
printer sets “OFF LINE” bit of MNSTS register to the optional
interface.
When the printer is initialized or returned to the idle state, the
parallel interface enters ready state and the serial interface sets
the DTR signal SPACE and the printer resets “OFF LINE” bit of
MNSTS register to the optional.
NOTE:An interrupt signal, such as /INIT, on the parallel interface is
not effective while that interface is not selected.
1.3.7.1 IEEE 1284.4 Protocol
The packet protocol described by IEEE1284.4 standard allows a device
to carry on multiple exchanges or conversations which contain data
and/or control information with another device at the same time across
a single point-to-point link. The protocol is not, however, a device
control language. It does provide basic transport-level flow control and
multiplexing services. The multiplexed logical channels are independent
of each other and blocking of one has no effect on the others. The
protocol operates over IEEE1284.
Automatic selection:
An initial state is compatible interface and starts IEEE1284.4
communication when magic strings (1284.4 synchronous
commands) are received.
ON:
IEEE1284.4 is enabled as initial state. Data sent before the magic
string (1284.4 synchronous commands) is discarded.
OFF:
IEEE1484.4 is disabled and IEEE1484.4 synchronous commands
are ignored. Compatible interface is the initial state.

EPSON Stylus Color 900 Revision C
Product Description Control Panel Operation 31
1.4 Control Panel Operation
The control panel of the EPSON Stylus Color 900 is composed of the 2
non-lock type push-buttons, 1 lock-type push-button, and 4 LEDs, as
shown below:
Figure 1-10. Control Panel
1.4.1 Indicators (LEDs)
1. Power
Lights when the operate switch is “ON”, and AC power is supplied.
2. Paper out
Lights during the paper-out condition, and blinks during the paper-
jam condition.
3. Ink Out (Black)
Lights during no Black ink condition, and blinks during the Black
ink low condition.
4. Ink Out (Color)
Lights during no Color ink condition, and blinks during the Color ink
low condition.
Power LED
Power Button
Load/Eject B utton
C leaning
B u tto n
In k O u t
(B la c k ) L E D
In k O u t
(C o lo r) L E D
Paper O ut LE D

EPSON Stylus Color 900 Revision C
Product Description Control Panel Operation 32
1.4.2 Panel Functions
Panel function: Refer to Table 1-17.
Table 1-17. Panel Functions
*1: 3 seconds is specified in the Users Guide.
*2: This operation is not effective in printing status.
Panel function with power on:Refer to Table 1-18.
Table 1-18. Panel Function with Power On
*1: The status print includes firmware version, ink counter, and nozzle check
pattern.
1.4.2.1 Printer Setting Mode
While turning the printer on, press the Cleaning button, and the Paper
Out LED starts blinking. This operation must be followed by pressing
the specified button while the Paper Out LED is still blinking to enter the
Default setting mode or Printhead alignment mode, as described in
Table 1-19.
Table 1-19. Printer Setting Mode
*1: Leaving the Paper Out LED blinking without pressing any button also generates
the Default setting mode.
*2: Not intended for users. This function is used only for troubleshooting.
See the following pages for detailed information on the default setting
mode and the Printhead alignment mode.
Button Function
Load/Eject
(within 2 seconds) *1
• Loads or ejects paper.
• When the carriage is in the I/C replacement position,
pressing this button returns the carriage to the capping
position.
Load/Eject
(for 2 seconds) *1
• Starts the I/C replacement sequence. *2
• Move the carriage to the I/C replacement position.
Cleaning
(for 2 seconds) *1
• Starts the printhead cleaning sequence.
• Starts the I/C replacement sequence when the printer
is in one of the following conditions:
“Ink Low”, “Ink Out”, No Ink Cartridge” *2
Cleaning
(within 2 seconds) *1
• When the carriage is in the I/C replacement position,
returns the carriage to the capping position.
Button Function
Load/Eject 1) Starts the status print. *1
Cleaning
Enters the printer setting mode. (The Paper Out LED starts
blinking.) *2
Specified button must be then pressed while the LED is
blinking to activate each mode. (See Section 1.4.2.1.)
Load/Eject
+
Cleaning
Enters the special setting mode. (Factory use only)
Specified button must be then pressed while the Paper Out
LED is blinking to activate each mode. (See Section
1.4.2.2.)
Button Function / Operation
Cleaning or no button While the Paper Out LED is blinking, pressing
the Cleaning or no button generates the
Default setting mode. *1
Load/Eject
(Press it within 10 seconds.)
While the Paper Out LED is blinking, pressing
the Load/Eject button generates the Printhead
alignment mode.
Load/Eject
(Hold it down for 10 seconds.) Changes the default for the parallel I/F
communication protocol. *2

EPSON Stylus Color 900 Revision C
Product Description Control Panel Operation 33
Default setting mode
Some printer setting parameters can be changed by users and will
be referred at the time of printer initialization. The setting method is
as shown below:
1. Enter the Default setting mode.
2. Select the desirable language for “Usage of this mode” by pressing
the Cleaning button.
3. Press Load/Eject button. The current setting and the “Usage of this
mode” in the selected language is printed.
4. Select the menu by pressing the Cleaning button.
5. Press the Load/Eject button to enter the value selection phase of
the selected menu.
6. Select the value by pressing the Load/Eject button.
7. Press the Cleaning button. The printer memorizes the selected
setting value, and returns the indication to the main menu.
8. Repeat the steps from 4 to 7. The menu selection will return to the
first menu after the last menu selection is over.
9. Turn the printer off. The new settings are stored in the non-volatile
memory.
Table 1-20. Default Setting Menu
Table 1-21. Default Setting Menu (continued)
*: Underlined values are the defaults for the EEPROM reset.
Font Roman, Sans Serif, Courier, Prestige, Script, Roman
T, Sans Serif H, Draft
Pitch 10 cpi, 12 cpi, 15 cpi, 17 cpi, 20 cpi, Proportional
Print direction Auto, Bi-D, Uni-D
Loading Position 3 mm, 8.5 mm, Others
I/F mode Auto, Parallel, Serial, USB, Optional
Auto I/F wait mode 10 seconds, 30 seconds
Network I/F mode
This mode is for the network environment only.
Off: Used in a usual environment.
On: Used in the network environment.
Parallel I/F transfer rate Fast, Normal
Software ESC/P2, IBM X24E
Auto CR (IBM mode only) On, Off
A.G.M (IBM mode only) On, Off
Auto line feed On, Off
0 slash 0, 0
Character tables
<Standard version>
Italic USA
Italic UK
Italic Italy
PC 850
PC865
Abicomp
PC 858
Italic France
Italic Denmark
Italic spain 1
PC 860
PC 861
Roman 8
ISO 8859-15
Italic Germany
Italic Sweden
PC 437
PC 863
BRASCII
ISO Latin 1
Character tables In addition to the Standard version:
<NLSP version > PC437 Greek
PC852
PC869
ISO 8859-7
PC 774
PC 866 LAT
PC 708
PC 437
PC 853
PC 857
MAZOWIA
ISO Latin 1T
Estonia
PC 866 UKR
PC 720
PC 855
PC 866
Code MJK
Bulgaria
ISO 8859-2
PC APTEC
PC AR864

EPSON Stylus Color 900 Revision C
Product Description Control Panel Operation 34
Printhead alignment mode
Alignment method is as described below:
1. While holding down both Load/Eject and Cleaning (Black) buttons,
turn the printer on.
2. Printer prints an instruction sheet that shows how to adjust the
printer and current alignment.
3. Referring to the current alignment, press the Cleaning button until
the LED indicate the appropriate test number.
4. Press the Load/Eject button. The printer prints the test pattern.
5. Referring to the test patterns on the new printout, select the most
closely aligned pattern by pressing the Load/Eject button.
6. Press the Cleaning button.
7. Repeat the steps from 3 to 6 until all test patterns are properly
aligned.
8. Turn the printer off.
1.4.2.2 Special Setting Mode
While turning the printer on, pressing the both Load/Eject and Cleaning
buttons generates the Special setting mode. While the Paper Out LED
is blinking, activate each function by pressing the specified button(s) in
the method described in Table 1-22.
Table 1-22. Special Setting Mode
Switch Function
Load/Eject
While the Paper Out LED is blinking, pressing
the Load/Eject button initializes the EEPROM
and resets the timer IC. (Refer to EEPROM
Address Map in Appendix.)
Cleaning
(Hold it down for 10 seconds)
While the Paper Out LED is blinking, pressing
the Cleaning button for 10 seconds resets the
waste ink counter in the EEPROM. (Refer to
EEPROM Address Map in Appendix.)

EPSON Stylus Color 900 Revision C
Product Description Control Panel Operation 35
1.4.3 Printer Condition and Panel Status
Table 1-23 shows printer condition and panel status. Since the table
shows various error status and also indicates printer status, it enables
you to find appropriate repair ways.
Table 1-23. Printer Condition and Panel Status
Printer Status
Indicators
Priority
Power Ink Out
(Black) Ink Out
(CMY) Paper Out
Power on condition On --- --- --- 9
Ink Sequence mode Blink --- --- --- 6
I/C replacement mode Blink --- --- --- 5
Data processing Blink --- --- --- 8
Paper Out --- --- --- On 4
Paper Jam --- Off Off Blink 3
No I/C, Ink Out (Black) --- On --- --- 7
Ink level low (Black) --- Blink --- --- 7
No I/C, Ink Out (CMY) --- --- On --- 7
Ink level low (CMY) --- --- Blink --- 7
Enters the EEPROM and
Timer IC Reset --- ON (for 1 second only) ---
Maintenance Request Blink Blink Blink Blink 2
Fatal Error Blink On On Blink 1

EPSON Stylus Color 900 Revision C
Product Description Error Status 36
1.5 Error Status
When any of the following status occurs, the printer goes in the error
status and stops receiving data, setting the /ERROR signal in the
interface to “Low”, and Busy signal to “High”. During this condition, the
printer is in non-printable status. Refer to Section 1.4.3 for detailed LED
Panel indicator status and corresponding error types.
1.5.1 Ink Out
When the printer has run out the most of the ink of any color, it warns of
Ink Low condition and keeps printing. When the printer runs out the
whole ink of any color, it stops printing and indicates the Ink Out error.
User is required to install a new ink-cartridge in this state. Note if an ink-
cartridge has been taken out, it should never be used again.
Reinstalling the used cartridge (not fully filled with ink) upsets the ink
level detection and may cause a serious problem in the printhead as a
result.
1.5.2 Paper Out
When the printer fails to load a sheet, it goes into the Paper Out error
condition.
1.5.3 Paper Jam
When the printer fails to eject a sheet, it goes into the Paper Jam error
condition.
1.5.4 No Ink Cartridge
When the printer detects that the ink cartridge has come off, it goes into
the No ink cartridge error.
1.5.5 Maintenance Request
When the total quantity of ink wasted through the cleanings and flushing
has reached the limit, printer indicates this error and stops printing. The
absorber in the printer needs to be replaced with a new one by a service
person.
1.5.6 Fatal Errors
When the printer detects the carriage control error or CG access error, it
enters the fatal error condition.
CAUTION
Never use an ink cartridge that has been removed.

EPSON Stylus Color 900 Revision C
Product Description Printer Initialization 37
1.6 Printer Initialization
The EPSON Stylus Color 900 is equipped with three types of
initialization methods.
Power-on initialization
The printer is initialized when it is turned on or recognizes the cold-
reset command (remote RS command). When the printer is
initialized, it performs the following:
(a) Initializes the printer mechanism.
(b) Clears the input data buffer.
(c) Clears the print buffer.
(d) Sets the default values.
Operator initialization
This printer is initialized when it is turned on again within 10 seconds
after last power off or recognizes the /INIT signal (negative pulse) of
the parallel interface. When printer is initialized, it performs the
following:
(a) Caps the printhead.
(b) Ejects a paper.
(c) Clears the input data buffer.
(d) Clears the print buffer.
(e) Sets the default values.
Software initialization
The ESC@ command also initializes the printer. When the printer is
initialized, it performs the following:
(a) Clears the print buffer.
(b) Sets the default values.

EPSON Stylus Color 900 Revision C
Product Description Component Layout 38
1.7 Component Layout
The main components of the Stylus Color 900 are as follows:
1) Printer mechanism
2) C265 Main board
3) C265 PSB/PSE board
4) C265 panel board
5) C265 relay board
1.7.1 Printer Mechanism
The printer mechanism of the Stylus Color 900 has black and color
heads united in one unit which drives larger amount of nozzles (180
nozzles in total) than ever. Also, for a new ink jet printer feature, the
printer has succeeded in printing in the acceleration/deceleration areas
by reading the slits on the linear scale to improve the throughput. This
improvement in throughput mostly depends on the Pump/ASF switching
mechanism. In other printers, the gear trains are switched when the
trigger lever hits the mechanism along with the carriage’s movement. In
Stylus Color 900, however, the exclusive solenoid is directly attached to
the mechanism instead. With the solenoid which switches drive at a
higher speed, the printer can control high-speed paper ejection system:
the printer bring the leading edge of the second sheet to the printing
position just before ejecting the first sheet.
The motors equipped with the printer are CR motor, PF motor, and the
Pump/ASF Motor, same as for the Stylus Color 800.

EPSON Stylus Color 900 Revision C
Product Description Component Layout 39
1.7.2 C265 Main Board
The main features of the C265 Main board are as follows.
1. IEEE1284 compliant
ECP mode is available
Type-B I/F is available
2. Mac serial I/F is available (at 900 K bps, 1.8 M bps, 3.6M bps).
3. USB full-speed is available (at 12 M bps without the hub).
4. All motors (CR motor, Pump/ASF motor, and PF motor) are
controlled with the micro step system (using up to 4W1-2 phase
excitation mode) and current attenuation mode (First, Slow, Mixed,
and Decay).
5. Intensive temperature control of the new type of the printhead:
operates the cooling fan using the thermistors and the abnormal
temperature detection circuit on the printhead board.
H8S2357, a CPU which is the hub of the C265 Main board, has an
internal flash memory with the size of 128 KB. Since the CPU runs with
24 MHz, it can send print data efficiently for a high throughput. The
C265 Main board has two independent exclusive ASICs, ASIC1 and
ASIC2. The former controls all interfaces but the USB I/F and sensors,
while the latter controls the printhead, motors, encoder, and USB I/F.
The combined IC (IC8) which has a normal timer IC and EERPOM in
one chip also features the printer. Since the EEPROM counts ink
consumption at the valuable printing *1, its size has increased to 2 K bit.
*1: The valuable dot system, or many-valued dot system, enables the
printer to freely fire three different sizes of dots (normal, middle, and
small dots) in one raster. In other printers, if the super micro dot
mode is once selected through the printer driver, the printers prints
only in the selected mode until the current print data is completed.
However, the valuable dot system of this printer enables the printer
to fire three different sizes of dots in one raster, and ink-jet specific
adverse conditions such as uneven printing and white banding are
improved as a result.
The C265 Main board is also equipped with a CG-ROM which deals
with DOS users. The CG ROM attachment condition and size are as
shown in Table 1-24.
Table 1-24. Relation between P-ROM and CG ROM
NOTE:The “X” in the table represents the version.
Destination P-ROM CG-ROM
Standard version 16 M (TEE01X) Not installed.
NLSP version 16 M (TEE01X) 16M (M160B16XA)

EPSON Stylus Color 900 Revision C
Product Description Component Layout 40
Figure 1-11. C265 Main Board
L ith iu m B a tte ry
IC1(CPU:H8S)
IC 2(E 05B 59)
IC 3(E 05B 60)
IC 4(O ne-tim e P R O M )
IC5(D-RAM )
IC6(CGROM)
(IC 11) PF M otor D river
(IC12) CR M otor Driver
IC8(Tim er & EEPROM )
CN14
CN9
CN8
CN1
CN3 CN4
CN2
CN-
12
CN-
16
CN-
11
CN10
CN5 CN6
CN15
CN13
Therm istor (detects tem perature
of the heat sink)
C harging/D ischarging driver
for driving the black nozzles
Q 5 (upper), Q 6 (low er)
C harging/D ischarging driver
for driving the color nozzles
Q 3 (upper), Q 4 (low er)
Heat Sink
Therm istor (detects tem perature
on the printhead board)
IC 16 (upper), IC 15 (low er)
H ead pre-driver
IC 13 (upper),
IC 14 (low er)
ASF M otor Driver

EPSON Stylus Color 900 Revision C
Product Description Component Layout 41
1.7.3 C265 PSB/PSE Board
There are two types of the C265 power supply board as listed below.
C265 PSB board:For America, Japan, part of South east Asia
C265 PSE board:The rest of all regions
The C265 PSB/PSE board uses the switching regulator system. Since
the C265 PSB/PSE board uses the power switch on the secondary side,
it keeps applying voltage to the primary side across the T1. Especially,
the heat sink to which the Q1 is attached can not be insulated due to the
circuit’s formation. Therefore, to avoid an electrical shock, be careful not
to touch the heat sink and other metallic parts simultaneously while
troubleshooting.
Figure 1-12. C265 PSB/PSE Board
W ARNING
Never touch the heat sink (radiation plate) on the Q1
with your bare hands as it is not insulated. Otherwise,
you will get an electrical shock.
T1(Trans) Q1(FET)
IC 51(+5V regulator)
D 51(D iode)
L1
(
N ose cut reactance
)
D 55(D iode)
C 11(for sm oothing)
F1(Fuse)
C 1(N oise cut capacitor)
CN3
CN2
CN1
Danger!

EPSON Stylus Color 900 Revision C
Product Description Component Layout 42
1.7.4 C265 PNL Board
The C265 panel board is composed of the three switches and four
LEDs.
Figure 1-13. C265 PNL Board
1.7.5 C265 Relay Board
The C265 relay board is installed to relay the following with connectors:
Power for driving motors and sensors
Control signals
If any of the connectors is connected to a wrong position during
assembly, the printer shows a fatal error at power on.
Figure 1-14. C265 Relay Board
LED 3 LE D 2
LED 1
LED 0
SW 2 SW 1 SW 0
CN1
112
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
C arriage hom e position (C R H P ) sensor
C arriage (C R ) M otor
Pum p/ASF M otor
Paper Feed (PF) M otor
C onnector from the C N 11
on the C 265 M ain B oard
C onnector from the C N 12
on the C 265 M ain B oard
Solenoid (S w itches A S F/PU M P
m echanism )
C ontrol P anel
ASF Sensor
PE Sensor
C onnector from the C N 10
on the C 265 M ain B oard
C onnector from the C N 16
on the C 265 M ain B oard
C onnector from the C N 15
on the C 265 M ain B oard

OPERATING PRINCIPLES

EPSON Stylus Color 900 Revision C
Operating Principles Overview 44
2.1 Overview
This chapter describes the operating principles of the printer
mechanism and electrical circuits.
2.2 Printer Mechanism Operating Principles
The EPSON Stylus Color 900 uses a new type of printhead. It has black
and color heads united in one unit which includes a total of 480 nozzles:
192 nozzles for black (96 nozzles x 2) and 96 nozzles for each color.
This printhead enables the printer to print 3 lines by one pass at 10-cpi
printing. Also, new ASF/pump switching mechanism offers higher
throughput with quick feeding motion at continuous printing by
combining the trigger solenoid and independent pump/ASF motor.
Production of PTS signal using the encoder belt also enables the printer
to improve printing accuracy, detect paper jam in the CR operational
range, and print during acceleration/deceleration (on normal paper / 360
x 360 dpi only).
See Figure 2-1 for the printer mechanism block diagram.

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 45
Figure 2-1. The Stylus Color 900 Printer Mechanism Block Diagram
PF drive gear (high-precision gear)
H igh-precision pinion
PF m otor
Flashing position (the 80th colum n side)
PTS encoder
Paper eject sub roller
B lack I/C detection lever
C R unit
C olor I/C detection lever
U nited printhead for black and color
Tim ing belt
Cap
V a lv e fo r c a p p in g
Pum p
C R H P sensor
C R guide shaft
P F ro lle r (p o w d e ry -c o a te d ro lle r)
Encoder belt
ASF sensor (for phase detection)
ASF cam
ASF drive shaft
Paper load rollers
PE (P aper E nd) sensor
Pum p/ASF m otor
ASF solenoid (for sw itching the
ASF, pum p gear trains)
C R m o to r

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 46
2.2.1 Carriage Mechanism
As shown in Figure 2-1, the carriage unit with the printhead on it moves
right and left, depending on the rotational direction of the CR (Carriage)
motor. Table 2-1 shows the CR motor specifications.
Table 2-1. CR Motor Specifications
The CR unit position is always memorized and controlled by the CRHP
(Carriage Home Position) sensor. This sensor confirms the CR position
to renew the memory at the following timing:
When power is turned on / off
When a head cleaning operation, including initial ink charge, is
performed.
When the printer returns to a ready status because the printer
has executed print job or receives no data for one second or
more.
See Table 2-2 and Table 2-3 which show the CRHP sensor
specifications and CRHP sensor switch mode, respectively.
Table 2-2. CRHP Sensor Specifications
Table 2-3. CRHP Sensor Switch Mode
If this sensor is defective or does not work, it does not detect the
carriage while the carriage is in the home position seek mode. In this
case, the printer cuts off electricity to the CR motor and shows a fatal
error.
Like the Stylus Pro5000, the Stylus color 900 also uses a linear encoder
to obtain secure carriage movement and accurate print timing. The
linear encoder reads slits on the encoder belt (linear scale) above the
timing belt to control the carriage. See Table 2-4 for the linear encoder
specifications.
No. Item Specifications
1 Motor Type 4-phase / 200-pole / HB-type stepping motor
2Drive voltage 42 VDC ± 5% (Applied to the driver)
3 Coil resistance 5.8 Ω ± 10%
4Drive mode Bipolar constant current drive
No. Item Specifications
1Type Photoelectrical transfer system
(SHARP GP1S73P2)
2Drive voltage 5 V ± 5%
3 Collector resistance 30 VDC or less
CR Position Switch mode Sensor output
Within the CRHP
range Open 0.7 VDC or less
Off the CRHP range Close 2.4 VDC or more

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 47
Table 2-4. Linear Encoder Specifications
The ASIC (IC2) reads the linear scale (increment: 1/180 inch) and
internally divides data by 8. The read information is used to produce
basic drive frequency for 2880-dpi trapezoidal waveform production.
If the encoder is defective or in an undetectable condition, the printer
generates a fatal error immediately after power on. This error occurs
before the carriage’s home position seeking operation.
Beside detecting the carriage position, the CRHP sensor also serves to
determine whether or not the carriage is working properly. If the setting
signals (pulses) sent from the encoder do not reach the specified level
while the CR is moving in the acceleration / constant / deceleration
modes in its operative range, the program consequently assumes that
paper is jamming or the carriage is operating irregularly, and shows the
paper jam error by bringing up the LEDs of the corresponding
combination.
The printer is equipped with 2 actuators used to detect the ink
cartridges in the carriage unit driven by the CR motor. The printer,
however, is designed to operate the actuators only when both black
and color ink cartridges are installed. See Table 2-5 and Table 2-6 for
the ink cartridge sensor specifications and ink cartridge sensor switch
mode, respectively.
Table 2-5. Ink Cartridge Sensor Specifications
Table 2-6. Ink Cartridge Sensor Switch Mode
If the ink cartridge sensor is defective or in an endetectable condition,
the printer shows No Ink Cartridge Error immediately after the printer is
turned on.
No. Item Specifications
1 Type Radiative Incremental encoder module
2 Drive voltage 5 VDC ± 5%
3Output
waveform Phase A/B 2-channel digital output (TTL level)
4Minimum step 1/180 inch (increment of the lines on the linear scale)
5Response
frequency 20 KHz
No. Item Specifications
1 Detection type Using a micro switch
2 Rated voltage 5 VDC ± 5%
3 Rated current 10 mA
4Contact resistance 50 mΩ
Cartridge Sensor Status Sensor Output
Absent Open 2.4 VDC or more
Present Closed 0.7 VDC or more

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 48
2.2.2 Printing Mechanism
The printing mechanism of the printer is all included inside the
printhead. The printing method is EPSON-exclusive MACH system,
which is used in other EPSON ink jet printers, but the printhead is not
compatible with any other printer. See Figure 2-2 for the printing
mechanism block diagram.
Figure 2-2. Printing Mechanism Block Diagram
The printing mechanism performs printing by applying voltage to the
PZT (integrated piezoelectric element) inside the printhead. With the
voltage applied to the PZT, the cavity, a tank filled with ink, is pressed
by the PZT and ejects ink from nozzles as the result. Unlikely to the
illustration, the actual number of the PZT included in the printhead in
this printer is 480, the same number as nozzles, and each PZT is
independently driven.
The steps below describes how the printing mechanism works.
1. Head drive pulse form command signal is output from the ASIC after
the printer is turned on.
2. Receiving the signal, the Pre-driver outputs the head drive pulse
signal to the driver.
3. If no printing data is sent, pulse output from the driver is not applied
to the PZT in the printhead: because the transistor on the nozzle
selector is not on.
4. If any printing data is sent from a PC, 5 serial data (3 for Y, M, and
C, and 2 for 2 rows of black) are sent to the nozzle selector from the
ASIC. Each serial data consists of 96 data since each row is
composed of 96 nozzles. When these data is all transferred, a Latch
signal is output from the ASIC to the nozzle selector after specified
period of time.
5. When the Latch signal is sent, a PZT signal is applied to the base
side of the transistor via the latch circuit in the nozzle selector.
6. Head drive pulse constantly output from the driver is then applied to
the PZT by the pulse output after a set of serial data and the latch
signal are all transferred.
7. The PZT drive pulse radiates large heat since it is driven with the
basic drive frequency of 32.4 K Hz and also has such a large
amount of drive elements as 480 PZT. Therefore, the abnormal
temperature detection circuit is included in the nozzle selector to
detect temperature of each nozzle so that heat radiation stays under
the maximum level. If the circuit detects abnormally high
temperature in any nozzle row, the printer regards the condition as
an accidental printing malfunction such as dot missing, and it
automatically enters the cleaning CL2, the most powerful cleaning
cycle. See the sensor descriptions in Chapter 2 for the operations
after this cleaning. The printhead also has the thermistor in it to
subtly change the voltage level of the drive pulse in accordance with
the temperature condition in use.
Nozzle
Selector
Pre-
Driver
+42
Driver
Data
Latch
Charge
D is-charge
PZT
Cavity
N
ozzle P late
ASIC
N ozzle
Pulse
Pulse form com m and
Tem perature data
Tem perature
detection
circuit Latch
circuit

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 49
[Nozzle configuration]
See Figure 2-3 for the nozzle configuration of the Stylus Color 900.
Figure 2-3. Nozzle Configuration
As shown in the figure, the black nozzles are aligned at 360 dpi
(vertical) and the color nozzles are aligned at 180 dpi. In the color
printing mode, only “B” row among 2 black nozzle rows is used and the
other row “A” is not used. (The same mechanism is used for the
microweave printing.)
2.2.3 Paper Load Mechanism
The paper load mechanism transports paper set in the hopper in the
ASF into the printer. It is operated by the ASF and the pump/ASF motor
which drive the ASF. The pump/ASF motor specifications are as shown
in Table 2-7.
Table 2-7. Pump/ASF Motor Specifications
The ASF rotates the semicircular roller once in reverse before
transporting paper into the printer. Along with this motion, the cam in the
semicircular roller pushes up the return lever. The return lever then
bounces up with tension spring force. As the result, some paper which
was fallen off the hopper during the previous feeding motion is all
aligned and set back in the hopper. This so called paper return
operation is performed for each paper feeding motion. Therefore, paper
loading accuracy is improved. See Figure 2-4 which shows how the
ASF feeds paper.
360 dpi
180 dpi
#1
#96 #96
#95
#94
#93
#2
#3
#95
#94
#93
#96
#95
#94
#93
#1
#2
#3
#1
#2
#3
#96
#95
#94
#93
#1
#2
#3
R ow A (B lack 1)
R ow B (B lack 2)
R ow C (M agenta)
Row D (Cyan)
Row E (Yellow)
No. Items Specifications
1 Type 4-phase / 48-pole / PM-type stepping motor
2Drive voltage 42 VDC ± 5% (Applied to the driver)
3 Coil resistance 7.0 Ω ± 10%
4Drive mode Bipolar constant current drive mode

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 50
After a paper loading motion is completed, the semicircular roller rotates
in the normal direction to load the top paper in the stack. This operation
is enabled by the correct phase of the gears in the ASF, because the
timings for the semicircular roller’s contacting the paper surface by the
corner (A) and the hopper’s being pushed out must be coincided. The
ASF sensor is used to determine the condition whether the phase is
correct or not. The transmission system of the ASF sensor detects the
condition by catching the position of the cam attached onto the same
shaft as the semicircular roller is. See Table 2-8 and Table 2-9 for the
ASF sensor specifications and its switch mode, respectively.
Figure 2-4. ASF Paper Load Mechanism
Table 2-8. ASF Sensor Specifications
Table 2-9. ASF Sensor Switch Mode
Note that torque from the pump/ASF motor is transmitted to the pump
unit depending on the pump/ASF mechanism condition. The rotational
directions and corresponding functions are as shown in Table 2-10.
Table 2-10. ASF/Pump Motor Functions
Sem icircular
ro lle r Cam
Pinch roller
H opper
R e tu rn le v e r S eparation pad
[R eady status]
[
Active Status
]
1)
2)
3) 4)
A
No. Item Specifications
1Type Photoelectric transfer system (transmission
type)
2Collector voltage 30 VDC or less
3 Coil resistance 5 VDC ± 5%
ASF Position Sensor Status Sensor Output
Home position Open 0.7 VDC or less
Off the home
position Close 2.4 VDC or more
Direction Functions for ASF Functions for the ink
system
Normal rotation
(CW)
• Reverse rotation of the
paper loading roller
(paper return control)
• Connection to the pump
gear train
• Normal rotation of the
pump (absorption)
• Releases the CR lock.
• Sets the wiper.
Reverse rotation
(CCW)
• Connection to the ASF
gear train
• Normal rotation of the
loading roller (paper
separation, paper
loading)
• Reverse rotation of the
pump motor
• Locks the CR.
• Resets the wiper.

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 51
2.2.4 Paper Feed Mechanism
The paper feed mechanism manages constant paper feeding during
printing through to paper ejection. Unlike previous models, the PF motor
of this printer only drives the paper feed mechanism, having no
connection with the carriage lock mechanism nor the pump mechanism.
See Figure 2-5 and Table 2-11 for the cross section of the paper feed
mechanism and the PF motor specifications, respectively.
Table 2-11. PF Motor Specifications
For the printer-specific feature, the PF motor pinion transfers torque to
the PF drive gear without any transmission gear in between. The gears
used for the PF motor pinion and the PF drive gear are very precise.
Therefore, note the points below when handling them:
1. Do not touch the gear surface with your bare hands.
2. Keep other parts or tools for servicing such as screw drivers away
from the gears.
The PE sensor in the paper feed mechanism is used to check the
following:
1. During paper loading, checks if the leading edge of the paper from
the ASF is correctly transported.
2. Checks if the paper loaded meets the specifications.
3. Checks if the paper is properly ejected after printing is over.
4. Checks if paper is jamming.
See Table 2-12 and Table 2-13 for the PE sensor specifications and the
PE sensor switch mode, respectively.
Table 2-12. PE Sensor Specifications
Table 2-13. PE Sensor Switch Mode
Figure 2-5. Paper Feed Mechanism
No. Items Specifications
1 Type 4-phase / 200-pole / HB-type stepping motor
2Drive voltage 42 VDC ± 5% (Applied to the driver)
3 Coil resistance 8.1 Ω ± 10%
4Drive mode Bipolar constant current drive mode
No. Item Specifications
1Type Transmission-type photoelectric transfer
system
2Drive voltage 5 VDC ± 5% (Applied to the driver)
3 Collector resistance 30 VDC or less
Paper
installation Switch mode Output voltage
Not installed Open 0.7 VDC or less
Installed Closed 2.4 VDC or more
PF m otor pinion
PF drive gear
Sub roller
Actuator
PE sensor
Paper
PF (pow dery-coated)
ro lle r
Paper ejection
ro lle r
N otched roller

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 52
2.2.5 Pump/ASF Switch Mechanism
The pump/ASF switch mechanism switches the motor’s torque between
the paper-loading and the pump-system sides. The pump/ASF motor
supplies torque, and a solenoid is used as switching trigger. (Refer to
Section 2.2.3 for the pump/ASF motor specifications.) Figure 2-6 shows
how the pump/ASF mechanism works when switching to the ASF gear
train.
[Switching to the ASF gear train]
Figure 2-6. Switching Operation to the ASF Gear Train
Figure 2-6 shows the gear condition after switching to the ASF is
completed. The steps below describe how the gears move to switch
from pump gear train to the ASF gear train.
1. In the pump gear train condition, the gear (3) in the planetary gear
set and the pump transmission gear are in mesh.
2. The pump/ASF motor rotates in the normal direction (CW).
3. The whole planetary gear set tries to move up, but the solenoid
suppresses it.
4. The solenoid comes on, allowing the whole planetary gear set to
move up. At this point, the gear (3) does not rotate, but the motor
pinion gear and gear (2) rotate in mesh.
5. The gears (3) and (4) come in mesh and connection to the ASF gear
train is fixed when a corner of the solenoid is aligned with the notch
in the planetary gear set.
6. Then the gears (4) and (5) are meshed. The gear (5) is connected to
the ASF drive gear in the printer mechanism to rotate the roller in
the ASF reverse (for paper return mechanism). (Refer to Section
2.2.3 for the paper return mechanism.)
Pum p/ASF m otor
Pum p transm ission gear
R eduction gear
Planetary gear set
Solenoid
ASF transm ission gear

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 53
[Switching to the pump gear train]
Figure 2-7 shows the gear condition after switching to the pump gear
train is completed.
Figure 2-7. Switching to the Pump Gear Train
The steps below show how the gears move to switch from the ASF gear
train to the pump gear train.
7. In the ASF gear train condition, the gears (3) and (4) are in mesh.
8. The pump/ASF motor rotates reverse (CCW).
9. The planetary gear set tries to move down, but the solenoid
prevents it.
10. The solenoid comes on allowing the whole planetary gear set to
move down. At this point, the gear (3) does not rotate, but the motor
pinion gear and the gear (2) rotate in mesh.
11. The gears (3) and (4) come in mesh, and the connection to the
pump gear train is fixed when a corner of the solenoid is aligned
with the notch in the planetary gear set.
12. The gear (4) meshes with the pump transmission gear in the printer
mechanism to perform CR lock and pump drive operations.
ASF transm ission gear
Pum p/ASF m otor
Planetary gear set
Solenoid
Pum p transm ission gear

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 54
2.2.6 Pump / Carriage Lock / Head Cleaner Mechanism
The pump mechanism operates in accordance with the carriage lock
and head cleaner control mechanisms. Figure 2-8 illustrates the
process of torque transmission from the pump/ASF motor to each
mechanism.
Figure 2-8. Pump / Carriage Lock / Head Cleaner Mechanism
Clutch
Spacer
C om pression spring
C leaner head
Fram e
Unlocked
Locked
O n the
sam e shaft
In the pum p gear train condition
Pum p interm ittent gear
Pum p transm ission gear
P re s s u re ro lle r
(le ft)
P re s s u re ro lle r
(rig h t)

EPSON Stylus Color 900 Revision C
Operating Principles Printer Mechanism Operating Principles 55
The steps below explain the process of driving each mechanism.
1. The precondition for driving the pump, carriage lock, and head
cleaner is that the pump/ASF switch mechanism is switched to the
pump gear train. (Refer to Section 2.2.6.)
2. Drive from the pump/ASF motor is transmitted via:
1) pump transmission gear (black) → 2) pump intermittent gear
(black) → 3) pressure roller (right) (pump drive roller: flesh color)
3. Along the way, the drive is also transmitted to the carriage lock
lever. The carriage lock lever is released with normal rotation of the
pump/ASF motor and set with reverse rotation of the motor.
4. Once the drive is transmitted to the pressure roller (right), all parts
used to drive the pump begin to act. The Stylus Color 900 has the
right and left pressure rollers. However, since the black and color
heads are included in one unit, the absorption tube is split in the
middle so the 2 pumps can absorb ink in the printhead. See Figure
2-9 which explains the ink absorption process.
5. The cleaner head is located between the pump frame and the
cleaner head drive roller, and a compression spring is set between
the cleaner head and the cleaner drive roller. Since the cleaner
head has a protrusion (marked with a red circle in Figure 2-8) on it
on the roller side, it moves back and forth along with the roller
rotation. However, if the roller rotates faster than the specific level, it
rotates alone because tension of the compression spring does not
work any more.
Figure 2-9. Ink Absorption Process
Separator
CCW
CW

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 56
2.3 Electrical Circuit Operation Principles
The Stylus Color 900 consists of the following circuit boards:
C265 main board
C265 PSB/PSE board
C265 Panel Board
2.3.1 C265 PSB/PSE Power Supply Board
This section explains the operating principles of the C265 PSB/PSE
board, in order.
AC power supply voltage is supplied from the AC power socket. Then
the fuse (F1) limits the incoming current of the AC voltage to avoid
damaging the C265 main board and C265 PSB/PSE board. On the
other hand, TH1 and TH2 serve to convert surplus input voltage into
heat energy.
The input voltage is next input to the RLC parallel circuit (a filter circuit),
for higher harmonics absorption. This operation keeps the higher
harmonics in the AC power out of the printer, and also prevents leakage
of higher harmonics generated in the printer.
After noise is removed, the AC voltage goes through the full-wave
rectification circuit. The minus component of the alternate wave is
eliminated as the result.
Then the voltage is smoothed by the electrolysis condenser (C11) for
stabilized DC voltage, and the current is applied to the primary side of
the transformer (T1).
The current, however, does not flow into the primary side of the
transformer (T1) if the main switching FET (Q1) located in the primary
side is off. The Q1 comes on when the voltage is applied to the gate
through the R28, a starting resistor, when the printer is turned on. While
the Q1 is on, current does not flow into the secondary side; because a
reverse-characteristics diode is used to connect to the secondary side.
The transformer (T1) is gradually charged with the current. When it is
full and not charged any more, the gate voltage of the Q1 starts going
down gradually. At this point, C13 abruptly pulls in the gate voltage of
the Q1 to turn the Q1 off.

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 57
Once the Q1 is off, the energy charged in the primary side flows into the
secondary side all at once. This occurs because the energy transfers in
the same direction as the reverse diode characteristics with the Q1 off.
The secondary side of the transformer (T1), which has the specified
numbers of coiling lines for 42 VDC production, creates the 42 VDC out
of the energy led to the secondary side by the electromagnetic
induction.
The secondary side has numbers of stabilizing circuits to output
stabilized voltages, as listed below:
Smoothing circuit:
Since the energy led from the transformer (T1) to the secondary
side by the electromagnetic induction is alternating current, it
must be smoothed by the electrolysis condensers C51 and C52
to be direct current.
+42 V line constant voltage control circuit:
7 zener diodes (ZD51, ZD81 - ZD86) connected in series
monitors +42 V status used to drive various mechanisms. To
keep the output voltage at a constant levelI, the circuit controls
the on/off timing of the Q1 slightly according to the signals fed
back from the photocoupler (PC1).
+42 V line overvoltage protection circuit:
This circuit includes 2 zener diodes (ZD52, ZD87) connected in
series. It monitors the +42 V line used to drive various
mechanisms to detect abnormal rise in the voltage level caused
by a defect in the circuit. If the output voltage rises to +48 V, the
signal is input to a port of one of the 2 channels in the
photocoupler (PC1) to completely cut off the Q1 operation. Once
this circuit is active, a normal flow does not recover unless the
printer is turned off and back on.
+5 VDC production circuit:
L4960 (IC51) produces +5 VDC out of +42 VDC. Since the IC
internally operates PWM control, it can always produce constant
+5 VDC by changing output pulses in spite of diverse input
voltage levels. This operation serves as a constant voltage
control circuit.
+5 V line overvoltage protection circuit:
ZD53 in the circuit monitors the +5 V line for overcurrent. In case
the voltage rises to 7 V for reasons such as a defective board,
the circuit shuts the Q1 gate in the same process as the +42 V
line overvoltage protection circuit follows.
Voltage drop delay circuit at power off
The C265 PSB/PSE board uses the secondary switch that
includes the delay circuit. The delay circuit allows the printer to
complete the power off operation properly even though the
printer is turned off while it is printing.
A normal power off operation by the user is monitored by the
C265 main board. When it detects a power off, the program
immediately starts the power-off sequence, capping the
printheads, and drops the power.
The electrolysis condenser (C84) continues to operate to allow
the printer to execute this proper power off sequence.
See the following page for the electrical circuit diagram.

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 58
Figure 2-10. C265 PSB/PSE Board Circuit Block Diagram
L
N
F1
R1
C1
TH1, TH 2
L1 C3,C4 C2 DB1 C
T1
Q1
PC1
Q2
Q3
+42V /0.8A
GP
+42
+42
+42
GP
ZD 51,
ZD 81-86
C 51,52
+5V /1.5A
GL
+5
PSC
+5
+5
GL
7
L51
OSC
5
C54
+
ZD53
ZD52
ZD87
L4960
(IC 51)
1
In
Q84
C84
+
Out
R28
300 K
Q31
C13
+5 V R egulator
D51
Incom ing current protection
H igher harm onics absorption Sm oothing
F u ll w a v e re c tific a tio n
Inrush current tem perature conversion
Starting resistor
H igher harm onics absorption
Sm oothing
5V line overvoltage protection
Sm oothing
42 V line constant voltage control
42 V line overvoltage protection
Voltage drop delay circuit at pow er off
C om es on w hen abnorm al.
Photo C oupler
Feed
back
Main
S w itc h in g
Feed
b a c k

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 59
2.3.2 C265Main Board
See Figure 2-11 for the C265 main board block diagram.
Figure 2-11. C265 Main Board Block Diagram
LB1847(IC 11)
C XA2128(IC 15)
A3957(IC 13)
A3957(IC 14)
C XA2128(IC 16)
LB1847(IC 12)
Q9
Q7
CN13
FAN
CN16
ASF S olenoid
CN8
H ead 1
CN9
H ead 2
CN12
ASF m otor
CN10
P F m o to r
CN11
CR moto
r
SN 75LBC
(IC 10)
74LV161284
(IC 9 )
PRO M
(IC 4 )
D-RAM
(IC 5 )
M-RAM
(IC 6 ) E05B60
(IC 3 )
E05B59
(IC 2 )
H D 64F2357
(IC 1 )
CN1
C entronics
CN3
Mac. Serial
CN2
Type B I/F
CN15
Sensors
CN4
USB
CRU1
R TC 9810
(IC 8 )
T93C 56
(IC 7 )
Tim er
/R S T

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 60
The following tables list the major components on the C265 main board
and their functions.
Table 2-14. Major Components on the C265 Main Board (1/2) Table 2-15. Major Components on the C265 Main Board (2/2)
Component Functions
CPU:
• A Hitachi H8-series CPU.
• Performs high-speed data processing running at 24.0
Mhz with an external transmitter.
• Bus width is 16-bit.
ASIC 1:
(E05B60: IC3)
• Controls all interfaces but USB.
• Monitors the signal from each sensor.
ASIC 2:
(E05B59: IC2)
• Controls printheads, motors, ASF solenoid, cooling fan,
USB I/F, and EEPROM.
PROM/MROM:
• For PROM, either one-time PROM or Mask ROM is
used. Specifications vary depending on the
destinations, as shown below:
<Standard version>
• PROM size: 16 M bit
• Contents: Unattached
• Bus width: 16 bit
<NLSP version>
• PROM size: 16 M bit
• Contents: 16 M bit
• Bus width: 16 bit
D-RAM: • Manages the various buffers and work area.
• Bus width is 16 M bit.
Timer IC:
(RTC9810: IC8)
• Counts total power off time of the printer, which offers
the basis for determining the cleaning type to be
performed at the next power on. Power is supplied by
an external button-cell battery (a lithium battery). This
IC also serves to produce reset signals connecting to
each major IC, such as CPU, ASIC1, ASIC 2, and motor
drive ICs. The head driver ICs (CXA2128 x 2: IC15 and
IC16) individually produce a reset signal when detecting
abnormal voltage so the printhead can stop in the
proper sequence.
Component Functions
Motor driver IC
(LB1847: IC11, 12)
(A3957: IC13, 14)
• The LB1847 (IC11 and IC12) is used to drive PF motor
and CR motor and enables 4W1-2 phase excitation
mode for the first in EPSON line. This control system,
called micro stepping, materializes the control of the
carriage vibration during printing and improvement of
accuracy in paper feeding on the hardware basis.
• The A3957 (IC13 and IC14) used to drive Pump, ASF
motor also supports the 4W1-2 phase excitation mode on
the hardware basis, but differs from the former IC in the
point that the IC13 and IC14 individually excite the phase
A and B.
Head driver IC
(CXA2128 x 2: IC15,
16)
• The head driver ICs, directory attached to the board,
consist of two separate circuits; charging circuit and
discharging circuit, to produce trapezoidal waveform.
This IC creates the trapezoidal waveform by combining
the signals input from the input port E05B59 (IC2) of the
IC. This is performed to change the characteristics and
voltage levels of charging and discharging, and the
trapezoidal waveforms specific to normal dot print and
micro dot print are produced as the result.

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 61
The control circuits are explained in detail below.
[Combined (reset circuit + timer) circuit]
A combined circuit RTC9810 manages both reset signal production and
RTC (Rear Time Controller). It produces reset signals by monitoring the
both 5 VDC line (input to Pin 7) and 42 VDC line (input to Pin 9). When
the voltage level for the 5 VDC line drops to 4.3 V, or the voltage level
for the 42 VDC line drops to 35.5 V, the combined circuit outputs a reset
signal from Pin 2. When the printer is turned on / off or detects abnormal
voltage level, the IC sends the reset signal to the following ICs to avoid
printer damage caused by run-away of the logic line and abnormal
operation of driver systems. Also, to let the motor driver IC execute its
job properly, the reset signal is once input to the convertor (setting
current production IC) on the main board to stop motors in the correct
sequence.
On the other hand, the timer control is done by counting the operation of
the oscillator circuit, and the printer’s power off time can be confirmed
based on the timer at the next power on operation. Also, this count data
is used to manage the timer for the operation such as periodical flashing
during power on time as well as power off time.
While the printer is on, the printer supplies 5 V (input to Pin 7) to operate
the internal oscillation circuit, however, when the printer is turned off,
the external button-cell battery (a lithium battery) immediately starts
supplying voltage (3 V) to the Pin 8.
Figure 2-12. Reset/timer combined circuit
+42 V
Speed up
diode
+5 V
R 18 107 K
R 20 10 K
BAT1
VIN
VDD
VBK
GND
9
7
8
14
/R S T
CE
SCLK
DATA
43
81
H D 64F2357(IC 1) E05B59(IC2)
2456
/R S T
36
E05B60(IC3)
252627
TCE
TCLK
TDATA
R TC 9810(IC 8)
/R S T
/R S T
LB1847(IC 11)
2
13 VREF1
VREF2
3.0 V
2
13
M 62383(IC 17)
12 /R S T
D/Axx
D/Ayx
D/Axy
3
4
8
LB1847(IC 12)
VREF1
VREF2
A3957(IC 13)
REF
A3957(IC 14)
REF
3
3
Devision
D rops to 35 V

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 62
[Sensor circuit]
The sensors attached to the printer are as described in the following
pages. They are basically divided into 2 major parts: 1) abnormal
temperature detection part and 2) mechanism status detection part. The
former is controlled by the CPU and the latter is controlled by 2 ASICs;
E05B59 (IC2) and E05B60 (IC3).
1) Abnormal temperature detection part
This abnormal temperature detection part is composed of 3 thermisotrs
and the temperature detection circuit which is included in the nozzle
selector inside the printhead. The CPU’s analog ports used for
temperature detection and their functions are as follows:
Figure 2-13. Sensor Circuit Block Diagram (Abnormal Temperature Detection Circuit)
ANO DE5
CN8
CN9
THM
N ozzle
Selector
4
H D 64F2357(IC 1)
Therm istor on the heat
sink on the m ain board
Location (TH 1) on the board
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
112
111
110
109
108
107
106
105
19
21
20
1
2
9
10
HDSAM I
HPDSAM I
THM
ANO DE1
ANO DE2
ANO DE3
ANO DE4
Printhead surface Inside the printhead
Row A
Row C Row D Row E
Row B

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 63
AN7 (Pin 112)
The TH1, located between 2 pre-driver ICs (the head driver ICs;
IC15 and IC16) on the main board, monitors temperatures around
the board. A Pre-Driver IC is exclusively developed to create
intricate trapezoidal waveforms which vary depending on the model.
It uses +42 VDC and high frequency to produce trapezoidal
waveforms. Therefore, if any relevant trouble has occurred, it is
assumed that the driver is overheated. The TH1 works to detect this
kind of unexpected rise in temperature at an early stage and stop
printing.
AN6 (Pin 111)
Four power transistors (Q3 - Q6) used for trapezoidal waveform
production are directly attached with screws to the large heat sink (a
radiation plate) on the main board. Since the printhead supported by
the Stylus Color 900 supports very high driving frequency (28.8
KHz), higher than ever, and a large amount of PZT, radiation from
the discharging transistor used for trapezoidal waveform production
is huge. Therefore, the cooling fan on the board forces out heat
around the radiation plate. A thermistor fixed on the radiation plate
sends signals to the AN6 port of the CPU to allow the CPU to
manage the cooling fan’s on/off operation.
AN5 (Pin 110)
The electrical signal input to this port is a temperature signal sent
from the thermistor included in the printhead unit. The function of
this thermistor is, same as before, to precisely detect temperatures
around the printhead and feed back information to the C265 main
board. Based on the fed back information, the printer manages
subtle change in the voltage level of the head drive trapezoidal
waveform, and also can eject the correct amount of ink as it is
aimed at any temperature.
AN4-ANO (Pins 1, 2, 9, 10, 4)
The nozzle selector IC is attached inside the printhead. It
determines which nozzle is used to fire ink according to serial data
sent from the ASIC (IC2). A temperature detection circuit included in
the nozzle selector detects the temperature of each actuator in the
5-row PZT array. This must be performed to avoid false firing. If the
printhead continues the firing motion, but no ink is ejected, the
temperature inside the printhead rises to 100 °C and the printhead
might be damaged as a result. To prevent this from happening, the
abnormal temperature detection circuit is included in the nozzle
selector circuit.
The followings are possible reasons for false firing:
1. If an ink cartridge has been removed before its life end and is
installed again, the ink consumption counter value is upset, and
the counter fails to detect the actual remaining ink level. This
wrong operation dangerously causes the printhead to keep
firing without any ink remaining in the cartridge.
2. Serious dot missing can also cause false firing. In this case,
there is enough ink in the cartridge, but it does not properly flow
into the head because of a clogged nozzle(s). If the PZT is
driven without any ink flow, heat generated by the nozzle
movement can not be released, and this makes the
temperature around the head abnormally high.
3. Strong vertical impact applied to the head causes a
considerable amount of ink around the nozzle to leak all at
once as well as damages meniscus on the head surface. As a
result, ink does not properly eject at the next printing and ends
up in a false firing status.

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 64
False firing is detected in the following conditions, and the printer
handles it as described below.
False firing detection timing:
If any of the 5 channels, which are monitored by the abnormal
temperature detection circuit in the nozzle selector, reaches 100
°C, the printer stops printing and automaticaly begins the
cleaning cycle. In this case, the printer runs the most powerful
cleaning cycle. The particular address bit called abnormal
temperature detection flag is reset at this point.
Process after detection:
The printer does not resume printing until the temperature
around the PZT recovers to the tolerable range. In case the
printer detects the same abnormal condition again, it indicates
an ink-end error to urge the user to replace the cartridge
considering the following possible reasons:
1. The currently installed ink cartridge is far beyond its useful
life (6 months). Ink, in this condition, does not eject properly
and results in a false firing. When a new cartridge is
installed, the problem is solved.
2. The cartridge installed has been repeatedly removed and
then installed again several times. With this mis-handling of
the cartridge, the ink consumption counter can not properly
describe the actual remaining ink level, and a false firing
occurs as a result. The solution in this case is also replacing
the ink cartridge with a new one.
Furthermore, If an ink cartridge is removed from the printer,
air comes in and bubbles inside the cartridge. Unlike a new
cartridge, the ink inside the removed cartrides is not
deaerated, so the bubbles inside can not be absorbed into
the ink due to the ink’s saturated condition. For this reason,
the more the cartridge is removed/installed, the more
bubbles are formed, and the printhead can not eject ink
properly and false firing occurs.

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 65
[Mechanism status detection part]
Figure 2-14. Sensor Circuit Block Diagram (Mechanism Status Detection Part)
CN9
20
21
COB
COC
+5
CN8
21
20
LS1
LS2
E05B59(IC2)
109
110
COB
COC
93
94
ENCB
ENCA
+5
E05B60(IC3)
SW C0
SW A1
SW A0
137
136
135
+5
+5
33
PSC
CN15
HP
PE
ASF
16
15
14
4
CN5
PSC
4
+5

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 66
Encoder:
This sensor increases accuracy of ink ejection timing. Irregular
movement of the carriage, usually caused by a paper jam, can be
also detected based on the change in input signals of this sensor.
Carriage movement is monitored by running the encoder belt (with
lines printed on it with increments of 180 dpi) between the photo
sensor attached to the carriage. Also, if the printer receiveds a large
impact during printing, the input signal cat not be properly read, and
in some cases print quality decreases with a dot missing problem.
This is because this printer forms one dot by producing trapezoidal
head driving waveforms based on the cycle determined by the
signals sent from the encoder.
Ink cartridge sensor:
If the printhead drives without any ink cartridge installed (= false
firing), it damages the printhead unit. Also, compared with other
printers, this printer uses the largest number of PZT and accordingly
releases more heat. For this reason, the ink itself inside the
cartridge serves to lower the temperature inside the cartridge, and
black and color ink cartridges can be separately detected to avoid
false firing.
Detection process: An ink cartridge is detected when the ink
cartridge being installed activates the actuators, which then pushes
the micro switch.
CR home position sensor:
When the printer is turned on, the CRHP sensor confirms the CR is
in the home position during the home position seeking sequence.
Then the printer can determine the CR control afterwards. The
printing column position is also confirmed based on the signals from
the sensor.
Detection process: The carriage is detected when the flag interrupts
the light beam in the photo sensor which is located on the right end
of the printer mechanism.
PE (Paper End) sensor:
The PE sensor detects the following conditions:
Whether or not paper is set at power on.
Whether or not paper is properly fed from the ASF with the
paper feed command.
Whether or not the printer properly ejects a page of printed
paper after rotating the PF (Paper Feed) motor with the
predefined distance.
Detection method: A photo sensor is used to detect the
actuator’s motion; the actuator is pushed/released by the
leading/rear edge of the paper.
ASF sensor:
Various parts in the ASF are engaged in the phase that is designed
to feed paper at the approariate timing. If the timing is wrong, mis-
match occurs between paper feeding by the ASF and paper
transportation for printing, and non-feeding or paper jam will occur.
Therefore, this printer monitors the sensor condition at power on
and before and after paper is fed/ejected according to the pump/
ASF motor’s roational distance.
Power on/off detection:
Unlike primary-side switch type products, ASIC E05B60 (IC3) on the
C265 main board is used to monitor the power on/off operation
instead of any sensor. When the power switch on the control panel
is turned off, the change from 5 V to ground level is detected at the
Pin 33 of the IC3, and the program starts the power off sequence
with this change. Power used during the sequence is supplied by
the electrolysis condenser C84 in the voltage drop delay circuit in
the secondary side of the C265 PSB/PSE board. The electrolysis
condenser continues to supply power until all electric charge inside
is completely discharged.

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 67
2.3.3 CR Motor Driver Circuit
An exclusive motor drive IC (LB1847: IC12) enables 4W1-2 phase
excitation on the hardware basis. A micro stepping motor is used for the
CR motor to move the carriage accurately and also to improve printing
accuracy by minimizing the motor’s vibration during printing. Figure
2-15 shows the CR motor driver circuit block diagram.
Figure 2-15. CR Motor Driver Circuit Block Diagram
+42
+5
+42 +42 +42 +42
CN11
1
2
3
4
D/Axy
8
E05B59(IC2)
7
6
9
8
14
28
15
25
24
23
22
18
19
20
21
27
16
26
17
2
13
3
12
147
148
149
150
163
162
161
160
143
170
144
169
171
172
LB1847(IC 12)
1
5
173
174
175
N.C.
M 62383(IC 17)
10
CRIA0
CRIA1
CRIA2
CRIA3
CRIB0
CRIB1
CRIB2
CRIB3
CRPHAA
CRPHAB
CRENBA
CRENBB
CRCTL0
CRCTL1
CRCTL2
CRCTLR
CRCTLS
Phase A setting
current signal
(16 patterns)
Phase B setting
current signal
(16 patterns)
Phase C R A (B)
selection signal
Phase C R A (B)
ENB (perm ission)
signal
M otor sub control
M D signal
DECAY signal 1
DECAY signal 2
N ot used
Phase A constant
at chopping
IA 1
IA 2
IA 3
IA 4
IB 1
IB 2
IB 3
IB 4
PHASE1
PHASE2
ENABLE1
ENABLE2
VREF1
VREF2
CR1
CR2
MD
DECAY1
SECAY2
OUTA
OUT-A
OUTB
OUT-B
VBB
VCC
GND
OUT A
OUT-B
OUT-A
OUT B

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 68
Unlike previous EPSON ink jet printers, the number of the phase
excitation input ports in the motor drive IC of this printer has increased
to 8. The previous micro step system used total of 4 phase excitation
input signals for both phases A and B. (Stylus COLOR, Stylus PRO
series, and Stylus PRO XL series are exceptional, since they transfer 4-
bit serial data from ASIC to the motor driver.) This is because the micro
stepping was controlled by the software only. On the other hand,
LB1847 enables the 4W1-2 phase excitation using the hardware and is
equipped with the necessary number of input ports (8 ports) for current
setting signals. Among these input ports, 4 ports are allocated to each
phase, A and B. Therefore, 16 types of current setting data can be
constantly sent to the driver IC. The LB1847 controls the micro stepping
system by exciting the corresponding phase based on the combinations
of the setting signals sent from the ASIC.
Table 2-16 shows the excitation modes used for the CR motor and their
usage.
Table 2-16. CR Motor Excitation Mode and Usage
Excitation mode Usage Minimum step
2-2 phase drive LQ print mode 1/120" (0.212 mm)
1-2 phase drive Not used 1/240" (0.106 mm)
W1-2 phase drive Sort skipping
SLQ print mode 1/480” (0.053 mm)
2W1-2 phase drive Wiping
Capping 1/960" (0.026 mm)
4W1-2 phase drive
Moving from the
capping position
Uncapping
1/1920" (0.013 mm)

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 69
2.3.4 PF Motor Driver Circuit
Motor drive exclusive IC (LB1847: IC11) enables 4W1-2 phase
excitation on the hardware basis. A stepping motor is used for the PF
motor to move the carriage accurately and also to improve printing
accuracy by minimizing the motor’s vibration during printing. Figure
2-16 shows the PF motor driver circuit block diagram.
Figure 2-16. PF Motor Driver Circuit Block Diagram
+5
+42 +42 +42 +42
CN10
1
3
2
4
D/Axx
3
E05B 59(IC 2)
7
6
9
8
14
28
15
25
24
23
22
18
19
20
21
27
16
26
17
2
13
140
139
138
137
133
134
135
136
142
128
141
129
124
127
LB1847(IC 11)
125
126
123
N.C.
M 62383(IC 17)
+42
PFIA0
PFIA1
PFIA2
PFIA3
PFIB0
PFIB1
PFIB2
PFIB3
PFPHAA
PFPHAB
PFENBA
PFENBB
PFCTL0
PFCTL1
PFCTL2
PFCTLR
PFCTLS
Phase A setting
current signal
(16 patterns)
Phase B setting
current signal
(16 patterns)
Phase C R A (B)
selection signal
Phase C R A (B)
ENB (perm ission)
signal
M otor sub
control
IA 1
IA 2
IA 3
IA 4
IB 1
IB 2
IB 3
IB 4
PHASE1
PHASE2
ENABLE1
ENABLE2
VREF1
VREF2
OUTA
OUT-A
OUTB
OUT-B
VBB
VCC
GND
PFF
A
PF -A
PF B
PF-B

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 70
Unlike the previous EPSON ink jet printers, the number pf the phase
excitation input ports in the motor drive IC of this printer has increased
to 8. The previous micro step system used total of 4 phase excitation
input signals for both Phase A and Phase B. (Stylus COLOR, Stylus
PRO series, and Stylus PRO XL series are exceptional, since they
transfer 4-bit serial data from ASIC to the motor driver.) This is because
the micro stepping was controlled by the software only. On the other
hand, LB1847 enables 4W1-2 phase excitation using the hardware and
is equipped with the necessary number of input ports (8 ports) for
current setting signals. Among 8 input ports, 4 are allocated to each
phase, A and B. Therefore, 16 types of current setting data can be
constantly sent to the driver IC. The LB1847 controls the micro stepping
system by exciting the corresponding phase based on the combinations
of the setting signals sent from the ASIC.
Table 2-17 shows the excitation modes used for the PF motor and their
usage.
Table 2-17. PF Motor Excitation Mode and Usage
Excitation phase Usage Minimum step
2-2 phase drive Not used 1/720"(0.035 mm)
1-2 phase drive
Fast feed 1
Fast feed 2
Special fast feed
1/1440"(0.018 mm)
W1-2 phase drive Not used 1/2880"(0.009 mm)
2W1-2 phase drive Middle-speed feed 1/5760"(0.004 mm)
4W1-2 phase drive
Normal feed
Micro adjust feed
Slow feed
1/11520"(0.004 mm)

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 71
2.3.5 Pump/ASF Motor Driver Circuit
Like for the CR motor and the PF motor, A3957 (IC13, IC14) enables
the pump/ASF motor to perform 4W1-2 phase excitation on the
hardware basis. Figure 2-17 shows the pump/ASF motor driver circuit
block diagram. Among 2 drivers, IC13 and IC14 drives the Phase A and
Phase B, respectively.
Figure 2-17. Pump/ASF Motor Driver Circuit Block Diagram
+42 +42 +42 +42
CN12
1
3
2
4
A3957(IC 13)
15
22
A3957(IC 14)
15
22
REF
M 62383(IC 17)
D/Axy
4
20
13
11
8
10
20
13
11
8
10
E05B59(IC 2)
69
68
62
64
63
81
80
72
74
73
ASFIA0
ASFIA1
ASFIA2
ASFIA3
ASFPHAA
ASFIB0
ASFIB1
ASFIB2
ASFIB3
ASFPHAB
ASF A
ASF -A
ASF B
ASF-B
Phase A specified
signal
Phase B specified
signal
Phase B setting
current signal
(16 patterns)
Phase A setting
current signal
(16 patterns)
OUTA
OUTB
OUTA
OUTB

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 72
Table 2-18 shows the excitation modes used for the pump/ASF motor
and their usage.
Table 2-18. Pump/ASF Motor Excitation Mode and Usage
2.3.6 Printhead Driver Circuit
The printhead driver circuit consists of 2 circuits: the common voltage
production circuit (a trapezoid waveform production circuit) on the C265
main board and nozzle selector on the printhead. The pre-driver
CXA2128 (IC15, 16) produces trapezoid waveform and the transistors
(Q3 - Q6) output it. Unlike previous products, data (serial data) is
independently transferred to each nozzle row to enable reduction in
data latch time required to form one dot, while nozzle selection is
performed by ASIC, which sends serial data directly to the nozzle
selector on the printhead synchronizing with the clock signal. (A block
diagram and the circuit diagram for the nozzle selector are not included
in this manual.) The printhead driver circuit block diagram is shown in
Figure 2-18.
Excitation phase Usage Minimum step
2-2 phase drive
Fast absorption
Semi-fast absorption
Fast feed
1/720" (0.035 mm)
1-2 phase drive Micro absorption 1/1440" (0.018 mm)
W1-2 phase drive Not used 1/2880" (0.009 mm)
2W1-2 phase drive Normal absorption
Normal feed 1/5760" (0.004 mm)
4W1-2 phase drive
Constant drive
Slow feed
Slow absorption
1/11520" (0.004 mm)

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 73
Figure 2-18. Printhead Driver Circuit Block Diagram
CN8
C XA2128(IC 15)
23
22
+42
C XA2128(IC 16)
5
17
6
13
14
20
18
16
23
22
20
18
16
28
27
26
25
3
4
5
29
30
1
28
27
26
25
3
4
5
29
30
1
114
113
112
111
120
119
118
115
116
121
E05B59(IC 2)
AN0
AN1
AN2
AN3
AN4
CPU(IC1)
CN9
COM e
1
20
21
17
15
6
7
19
9
11
13
4ANO DE5
AN5
105
106
107
108
109
110
19
1
2
9
10
110
109
107
102
97
98
99
100
101
108
Q3
Q4
Q5
Q6
F1
COC
COB
HLAT
HSOCLK
HSO_Y
HSO_M
HSO_C
HSO_B1
HSO_B2
HINV
HW A0
HW A1
HW A2
HW A3
HW CLK1
HW CLK2
/H W F L R
HW SDATA
HW SLC
/H W S L A T
A0
A1
A2
A3
CLK1
CLK2
/FLOOR
DATA
DCLK
/E
VCC45
VC C 45_2
NPNB
FB
PNPB
C harging/discharging
circuit for color nozzles
Black nozzle row s
C o lo r n o z z le ro w s
H ead tem perature
detection circuit
AN data
(tem perature
detection
fo r e a c h c o lo r)
I/C detection signal
- D ata latch signal
- N ozzle selection signal
- C lock signal
Trapezoid w aveform
reverse signal
C o lo r n o z z le ro w
C harging/discharging
circuit for black nozzles
A0
A1
A2
A3
CLK1
CLK2
/FLOOR
DATA
DCLK
/E
VCC45
VC C 45_2
NPNB
FB
PNPB
VHV
COM a
COM b
COM c
COM d
THM
ANO DE1
ANO DE2
ANO DE3
ANO DE4
COC
COB
LAT
CLK
Y
M
C
B1
B2
IN V

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 74
2.3.7 Cooling Fan Driver Circuit
Since this printer drives a large number of PZT elements (total of 480
nozzles) with a high drive frequency (maximum 32.4 K Hz), heat
radiated around the printheads and the trapezoid waveform production
circuit on the C265 main board is considerably large compared to other
printers. Therefore a thernmistor is attached to the heat sink fixed to
thetrapezoid waveform production transistors to prevent the trapezoid
waveform production transistors (Q3 - Q6) and adjacent HIC from
operating abnormally due to high temperature. When the thermistor
detects abnormally high temperature, the printer turns the cooling fan
on to forcibly blow out heat from the lower case. Figure 2-19 shows the
cooling fan driver circuit block diagram. Table 2-19 shows how the
signals output from the ASIC and corresponding fan conditions.
Figure 2-19. Cooling Fan Driver Circuit Block Diagram
Table 2-19. Cooling Fan Control by the ASIC (IC2)
Figure 2-20 shows the main routine of the cooling fan drive.
Figure 2-20. Main Routine of the Cooling Fan Drive
ASIC (IC2, 176- pin) condition Cooling fan condition
High (5 VDC) On
Low (0 VDC) Off
+42
6.8
CN13
GND
2
1+35
39 K
E05B 59(IC 2)
176
FAN
FAN
F6
D rops to 35 V.
Start
YES YES E rro r 1
NO
YES Fan O n
YES Fan O ff
NO
NO
YES
NO
E rro r 1
R e tu rn to th e S ta rt.
t1 = H eat sink tem perature on the C 265 m ain board
t2 = TH 1 tem perature on the C 265 m ain borad.
Is
th e fa n
ro ta tin g ?
t1 >/= 50 °
C
or
t2 >/= 55 °
C
t1 >/= 60 °
C
or
t2 >/= 60 °
C
t1 >/= 40 °
C
or
t2 >/= 50 °
C
t1 >/= 36 °
C
or
t2 >/= 42 °
C
NO

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 75
Whether or not the cooling fan is driven depends on the electrical
signals sent from the 2 thermistors (“t1” and “t2” in the figure). The “t1”
represents the temperature detected by the thermistor attached to the
heat sink on the C265 main board with a screw, while the “t2”
represents the one between the printhead pre-driver ICs (IC15 and
IC16) on the C265 main board. Table 2-20 shows the thermistor
condition and corresponding fan operation.
Table 2-20. Conditions for Driving the Cooling Fan
Even while the printer is in idle status, the thermistors continue to detect
temperatures every 2 seconds for the cooling fan operation. However, 2
error status conditions can be detected in the main routine, since air
may not cool down if the fan is defective or the ventilation grill is
clogged.
[Error 1]
The printer does not stop printing but continues to print by lowering the
drive frequency. For instance, the printer normally prints with the head
drive frequency of 14.4 K Hz to perform 1440-dpi print (horizontal) at
200 cps (CR speed). In the error condition, however, the printer can
lower the head drive frequency to 7.2 K Hz by reducing CR speed to
100 cpi. Note the printer actually performs printing at 1/3 duty / 1-pass
of a normal speed.
[Error 2]
The printer stops printing. In this condition, the temperature at the
junction of the power transistor for trapezoidal waveform production and
the trapezoid waveform production IC (pre-driver) has risen to the limit
(which means the thermistors have detected over 60 °C at both t1 and
t2), and the printer generates a fatal error after stopping printing
completely. Therefore, this printer specifically shows a fatal error on the
control panel when detecting abnormal temperatures in addition to the
following 2 common conditions.
1. Failure in CR home position detection:
This failure can be caused by one of the following 4 reasons:
- CRHP sensor itself is defective.
- There is a deficiency in the circuit.
- Incorrect PG adjustment
- CR motor is defective
2. Failure in ASF home position detection:
This failure can be caused by one of the following reasons:
- ASF sensor itself is defective.
- There is a deficiency in the circuit.
- ASF is damaged.
- Pump/ASF motor is defective.
Thermistor condition Cooling fan:
Operating Cooling fan:
Stops operating.
t1 and t2 have detected
temperatures. t1 ≥ °40 C or t2 ≥ 50 °Ct1
≥
°
36 C or t2 ≥ 42 °C

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 76
2.3.8 ASF Solenoid Driver Circuit
A planetary gear is used in the gear train which switches between paper
feed operation from the ASF and pump operation. The switching action
is enabled by the solenoid. See Table 2-21 and Figure 2-21 which show
ASF solenoid specifications and the ASF solenoid control circuit block
diagram, respectively.
Table 2-21. ASF Solenoid Specifications
Table 2-22 shows the ASIC’s (IC2) conditions for driving the ASF
solenoid.
Table 2-22. Conditions for Driving the ASF Solenoid Figure 2-21. ASF Solenoid Control Circuit Block Diagram
No. Items Specifications
1 Type Single-phase DC solenoid
2Drive voltage 42 VDC ± 5%
3 Coil resistance 588 Ω ± 10% (at 20 °C)
4Induction 0.98 N (100 gf) or more
ASIC’s (IC2, 83-pin) condition Solenoid’s condition
High (5 VDC) Inducting
Low (0 VDC) Non-inducting
CN16
GND
2
1VBB
+42
F4
E05B 59(IC 2)
ASF_SO L 83
Q9
Q8
C ooling fan

EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 77
2.3.9 EEPROM Control Driver Circuit
Data for various factory-adjustment items is stored in the EEPROM
(IC7) on the C265 main board. The size of the EEPROM is 2 K bit since
various types of dots are available with this printer and memory
allocated for the ink consumption counter is accordingly large.
When the printer is turned on, data stored in the EEPROM is transferred
to the D-RAM by the ASIC (IC3). In the D-RAM, the ASIC controls
various adjustment values, total ink consumption, and current ink usage
condition for each color, and the printer prints depending on these
values. When the printer is turned off, the data and adjustment values
accumulated and controlled in the D-RAM are written back into the
specific addresses in the EEPROM under the ASIC’s control.
Information is transmitted between the ASIC (IC3) and the EEPROM in
the serial data format.
Figure 2-22. EEPROM Control Circuit Block Diagram
Address
Data
AT93C 56(IC 7)
Vcc
ORG
GND
+5
5
6
8
CS
SK
DI
DO
E05A 60(IC 3)
ECS
ESK
EDI
EDO
1
2
3
4
29
30
31
32
DRAM(IC5)

TROUBLESHOOTING

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 79
3.1 Overview
This chapter describes how to troubleshoot problems. It consists of the
sections shown in the flowchart below. When identifying and
troubleshooting problems, be sure to proceed to the correct section
specified in the flowchart.
Figure 3-1. Troubleshooting Flowchart
Following sections show detailed information on each step in the
flowchart. Be sure to perform troubleshooting without neglecting the
correct order specified in each section.
Yes
No
Troubleshooting w ith
LED error indications
(S ection 3.1.1)
(S ection 3.1.3)
Is the printer pow er on?
Isolating the faulty part
on the pow er supply
board
(S ection 3.1.2)
Isolating the faulty part
according to the
exhibited phenom enons

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 80
3.1.1 Troubleshooting with LED Error Indications
This section describes how to troubleshoot the problem when the
printer indicates an error at power on and can not print. The Stylus
Color can detect the following six errors and indicates them with the
LEDs, as shown below.
Table 3-1. Error Indication with the LEDs
NOTE: “---” means the LED is not affected by the error condition.
See the following tables which show the error conditions and
corresponding possible causes.
Table 3-2. Error Condition and the Possible Causes
Error Condition
Corresponding Combination of the LED Condition
Power Ink Out
(Black) Ink Out
(Color) Paper Out
Paper Out Error On --- --- On
Paper Jam Error --- Off Off Blink
No I/C or Ink Out
(Black) Error --- On --- ---
No I/C or Ink Out
(Color) Error --- --- On ---
Maintenance
Error Blink Blink Blink Blink
Fatal Error Blink On On Blink
No. Error Condition Possible Causes
1 Paper Out Error
(Refer to Section
3.1.1.1.)
1. Failure in paper feeding
2. Connector for the PE sensor is disconnected.
3. The PE sensor actuator is acting improperly.
The sensor base is not fixed properly.
4. The PE sensor is defective.
5. ASF is damaged.
2Paper Jam Error
(Refer to Section
3.1.1.2.)
1. The paper in use is longer than specified.
2. The encoder at the back of the carriage is covered
with dust.
3. The encoder at the back of the carriage is almost
dislocated. If it has completely come off, a fatal error
occurs.
4. The PE sensor remains on because it is covered
with paper debris or dust.
5. The PE sensor actuator is not acting properly.
The sensor base is not fixed properly.
6. The PE sensor is defective.
The encoder is defective.
7. The ASF is not installed properly.
The paper load sub roller is not fixed properly.

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 81
Table 3-3. Error Condition and the Possible Causes (continued) 3.1.1.1 Remedies for Paper Out Error
This section provides check points and corresponding actions which are
necessary when the Paper Out Error problem has occurred because of
either of the following reasons:
Paper is set in the ASF hopper but not fed.
Paper is fed but not detected by the printer.
Be sure to follow the steps in the order described in the tables.
NOTE: If the finding for the question is Yes, take the action described in
the right column. If “No”, proceed to the next step.
No. Error Condition Possible Causes
3 NO I/C or Ink Out
Error
(Refer to Section
3.1.1.3.)
1. The counter is not showing the actual remaining ink
level.
2. Ink cartridge sensor actuator is not acting properly.
3. The micro switch is not mounted correctly.
The connector (green) is disconnected.
4. The connector (green, 3-pin) on the small board
directly attached to the printhead surface side is
disconnected. Note the connector (green, 4-pin) is
irrelevant as it is for the encoder.
5. The micro switch is defective.
6. The value for the ink consumption counter in the
EEPROM is destroyed.
7. Ink cartridge replace command is generated because
an abnormal temperature is detected.
4 Maintenance
Error
(Refer to Section
3.1.1.4.)
Usual waste ink over-flow is requested.
Note this error can be cleared by the special function
through the control panel operation only.
5 Fatal Error
(Refer to Section
3.1.1.5.)
1. The CRHP sensor has come off.
The connector for the CRHP sensor is disconnected.
2. The encoder belt has come off.
The encoder belt is not placed through the encoder
located at the back of the carriage.
3. The ASF sensor has come off.
The connector for the ASF sensor is disconnected.
4. The coil for the CR motor has burnt.
5. The coil for the PF motor has burnt.
6. The lever fixing the planetary gear has come of the
frame.
The tension spring is dislocated.
7. Coil for the pump/ASF motor has burnt.
8. The coil for the ASF solenoid has burnt.
9. The CRHP sensor is defective.
10. The ASF sensor is defective.

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 82
Table 3-4. Remedies for Paper Out Error Table 3-5. Remedies for Paper Out Error (continued)
Step Check point Actions
1 Is no paper
loaded? Set a cleaning sheet in the ASF up side down. Then
holding the top edge, press the Load/Eject button, and
the micro pearl on the paper load roller (a semicircular
roller) surface is removed. To remove severe smear,
staple a cloth moistened with alcohol to a post card and
clean the roller in the same manner.
2 Is the connector
for the PE sensor
disconnected?
Connect the connector (yellow, 3-pin) for the PE sensor.
3 • Is the PE
sensor
actuator acting
improperly?
• Is the sensor
base floating?
• Using your hand, try activating the actuator in the
same condition as it is detecting incoming paper. Then
release the actuator and check if the actuator
automatically returns to its original position with the
tension of the spring.
• Referring to the illustration above, check that the
sensor base is securely installed to the frame. If the
sensor base is floating or installed insecurely, instal it
securely.
C L Sheet
N on-adhesive A rea
Adhesive A rea
This side dow n
(U se a post card
for the base sheet.)
Staplers
C loth m oistened
w ith alcohol
Bottom view of the printer m echanism
C onnector for the
PE sensor Tension spring
Step Check point Actions
4 Is The PE sensor
defective? Measure the voltage at the yellow 3-pin connector
on the relay board by activating the actuator
manually to check that the voltage is correct as
follows.
The actuator is activated: 2.4 V or more
The actuator is released: 0.7 V or less
5 Is the ASF damaged? Hand-rotate the shaft in the ASF in the paper feed
direction and check if the hopper hops out every
time you rotate the shaft.
NOTE: Even though the ASF sensor is in the
proper condition for detecting the HP
sensor, If the hopper is not operating at the
correct timing for paper feeding, paper is
not loaded. Therefore, if the ASF sensor is
working without this correct combination,
reassembly or replace the ASF.
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
Pin 3 (PE)
Pin 2 (G ND)

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 83
3.1.1.2 Remedies for the Paper Jam Error
This section includes the check points and corresponding actions which
are necessary when the Paper Jam Error constantly occurs when the
printer is turned on or feeding paper.
Be sure to follow the steps in the order described in the tables.
NOTE: If the finding for the question is Yes, take the action described in
the right column. If “No”, proceed to the next step.
Table 3-6. Remedies for Paper Jam Error
Step Check Points Actions
1 Is the paper length
beyond the
specifications?
Instruct the user that the Paper Jam Error occurs
if paper whose length is beyond the specifications
is used.
2 Is the encoder located
at the back of the CR
covered with dust?
Check if there is any dust or paper debris lodged
between the parts of the encoder (a transmission
type photo sensor) located at the back of the
carriage.
3 Is the encoder belt
nearly dislocated from
the encoder?
Referring to the illustration above, check if the
encoder belt is nearly dislocated from the
encoder.
4 Is the PE sensor always
on because of the paper
debris or dust
accumulated over the
sensor.
Viewing the PE sensor from the front, check that
the actuator is the correct position: the actuator
falls in the cutout without any paper.
Linear Scale
(E ncoder belt)
Encoder
C arriage U nit
PE Sensor
Actuator
PE Paper G uide
A ssem bly (R ight) PF Roller

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 84
Table 3-7. Remedies for Paper Jam Error (continued) Table 3-8. Remedies for Paper Jam Error (continued)
Step Check Points Actions
5 • Is the PE sensor
actuator acting
improperly?
• Is the sensor base
floating?
Referring to Step 3 in Section 3.1.1.1 “Remedies
for Paper Out Error”, check the sensor condition.
6 • Is the PE sensor
defective?
• Is the encoder
defective?
Referring to Step 4 in Section 3.1.1.1 “Remedies
for Paper Out Error”, check the sensor condition.
Then, verify the encoder sensor condition by
checking the following points for proper connection
and electrical continuity, since checking the signal
directly from the encoder is impossible.
1. Connection of the connector 1
2. Connection of the connector 2
3. Electrical continuity of the cable.
C arriage view ed from the back
H ead surface
C onnector 1 C heck for
continuity.
C onnector 2
Step Check Points Actions
7 Is the ASF installed
improperly?
Is any of the paper load
sub rollers fixed
improperly?
• Check the ASF installation at the following 2
points: View A and View B in the figure below.
• Viewing the printer from the back, check that all
of the six torsion springs securing the paper
load sub rollers are properly installed.
View B
View A
Protrusion is set in here.
View B
D isconnected
View A
Top Fram e Tension Spring

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 85
3.1.1.3 Remedies for No I/C and Ink Out Errors
This section includes the check points and corresponding actions which
are necessary when the black ink (or color ink) LED comes on or blinks
at power on despite the ink cartridge has been replaced with a new one.
Be sure to follow the steps in the order described in the tables.
NOTE: If the finding for the question is Yes, take the action described in
the right column. If “No”, proceed to the next step.
Table 3-9. Remedies for No I/C and Ink Out Errors
Step Check Point Actions
1 Does the counter
value mis-match the
actual remaining ink
level?
The ink consumption counter, separately set for black
and color ink, adds up points according to ink weight
used to form one dot. This counter is reset (the value
returns to zero) when the I/C replacement sequence is
performed. If the counter is reset for any other
purposes, the following adversities will occur.
1. Enough ink is remaining in the cartridge, but the
printer shows the Ink low or Ink end condition and
can not continue to print.
2. Ink has run out but the printer continues to print and
starts false firing, which damages the printhead.
Explain the situation to the user well, and replace the
I/C with a new one.
2 Is the ink cartridge
sensor actuator
acting improperly?
Turn the both actuators (eight and left) manually and
check that they properly push the micro switches.
Then, also check that the actuators return to their
normal conditions shown in the figure below
automatically.
M icro Sw itches
Actuator 1 Actuator 2

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 86
Table 3-10. Remedies for No I/C and Ink Out Errors (continued) Table 3-11. Remedies for No I/C and Ink Out Errors (continued)
Step Check Point Actions
3 Is the micro switch fixed
improperly?
Is the connector (green)
disconnected?
If the micro switch is not properly attached, the
actuators possibly fail to touch the micro switch.
Therefore, check that the micro switch is
securely attached to the carriage by the hooks.
4 Is the connector (green,
3-pin) disconnected form
the small board which is
directly attached to the
head surface side?
Remove the printhead and check if the connector
(green, 3-pin) is disconnected from the small
board at the bottom of the printhead.
Note: The green 4-pin is irrelevant as it is for the
encoder.
5 Is the micro switch
defective?
1. Keeping the left micro switch pressed down,
place the probes of the tester to the middle
and left pins to check for electrical continuity.
2. Keeping the right micro switch pressed down,
place the probes of the tester to the middle
and right pins to check for electrical continuity.
H ooks
C onnector M icro S w itches
Step1 Step2
Push 1 Push 2
Step Check Point Actions
6 Is data in the EEPROM
destroyed? If the address for the ink consumption information
in the EEPROM is garbled and the printer shows
the Ink Out (Ink End) error constantly, the printer
sets the interface signal “BUSY” to High and stops
communication with any other peripheral devices.
Therefore, it is effective to replace the I/C with a
new one to forcibly overwrite the address with 00H.
7 Is the abnormal
temperature detection
circuit working?
Since the Stylus Color 900 drives a large number
of PZT with a high drive frequency, if the printhead
is driven without any ink filled in it, the printhead
abnormally heats up and may be damaged as the
result. Therefore, this printer monitors and controls
the temperature around the printhead more strictly
than any other printers do. In case the printer
detects abnormal rise in head temperature during
printing, it generates the I/C replacement
command after the sequence described below.
1. Detects an abnormal temperature during
printing.
2. Stops printing and begins a head cleaning. (This
operation solves the nozzle clogging problem in
most cases.)
3. Resumes printing.
4. If detects an abnormal rise in the head
temperature again, sets a flag and generates
the I/C replacement command. (The Ink LED
comes on.)
The printer mostly enters this sequence under the
following two conditions:
• Ink around the nozzles is severely viscous. (due
to removal and reinstallation of the I/C)
• Ink is leaking from the printhead because of a
large impact.
The temperature in the printhead actually rises
abnormally when half the nozzles in any nozzle
row are clogged, or 48 nozzles in any 96-nozzle
row are clogged.

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 87
3.1.1.4 Remedies for the Maintenance Error
While the printer is in this error condition, it disables all operations
including data communication except for the panel operation specified
to clear the error. Therefore, follow the steps described in Table 3-12 to
solve the problem.
Table 3-12. Remedies for the Maintenance Error
NOTE: During the Step 2, if the Load/Eject button is pressed, the
Maintenance Error is not cleared but the EEPROM initialization
mode is activated instead. The EEPROM initialization can be
used to recover from conditions such as the printer does not
accept any data from the PC. The EEPROM initialization mode
initializes the following items:
Accumulated power-off time:The value for the Timer IC is reset.
CL Timer: The CL timer, which is also called fire-
waiting timer, secures the printer
specific period of time so bubbles
formed around the printhead during a
cleaning vanish.
I/F selection: Selects “Auto”, the factory default,
from 4 I/F selection items: Auto,
Parallel, Serial, and Option.
Step Actions Correct LED condition
1 Turn the printer on while pressing the
Load/Eject and the Cleaning buttons, and
the Paper Out LED starts blinking. (Blinks
for three seconds.)
The Paper Out LED is blinking.
2 While the Paper Out LED is blinking (for
three seconds), press the Cleaning button
for ten seconds.
The following three red LEDs
are blinking: Ink Out LED
(Black), Ink Out LED (Color),
and Paper Out LED.

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 88
3.1.1.5 Remedies for Fatal Error
A fatal error is basically caused by any of the following conditions:
1. The printer does not detect the carriage in the home position.
2. The printer does not detect signals from the linear scale.
3. The ASF sensor does not detect the ASF home position.
The following tables show various causes of the error and
corresponding solutions. Be sure to follow the steps correctly to solve
the problems.
NOTE: If the finding for the question is Yes, take the action described in
the right column. If “No”, proceed to the next step.
Table 3-13. Remedies for Fatal Error
Table 3-14. Remedies for Fatal Error
Step Check Point Actions
1 Has the CRHP
sensor come off the
printer mechanism
frame?
Is the connector for
the CRHP sensor
disconnected?
Check the CRHP sensor visually. Connect the
connector properly. Make sure the connector is
connected to the indicated position on the relay
board. Also, check that there is no dust nor paper
debris between the sensor parts.
2 Has the encoder belt
come off? Referring to step 2 in Section 3.1.2.2, check that the
encoder belt is set between the sensor parts. Also
check that the sensor is free from dust and paper
debris.
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
C onnector 1
C onnector 2
M echanism
Fram e
Step Check Point Actions
3 Has the ASF sensor
come off?
Is the sensor for the
ASF disconnected?
Referring to the figure below, check that the ASF
sensor is attached to the correct position.
Check that both connectors 1 and 2 are securely
connected.
4 Has the coil for the
CR motor burnt? Since the CR motor is controlled by the Bipolar
system, measure the coil resistance using the tester
as shown below.
<Resistance: 5.8 Ω ± 10%>
Note: Be
sure to
measure the
resistance at
two points
shown in the
figure below.
5 Has the coil for the
PF motor burnt? Measure the internal coil resistance of the PF motor
in the same manner as for the CR motor.
<Resistance: 8.1 Ω ± 10%>
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
AS F S ensor
AS F Fram e
(Left)
C onnector 1
C onnector 2
To Pin 1
To Pin 3
Step 1
Step 2
To Pin 2
To Pin 4
CR Motor

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 89
Table 3-15. Remedies for Fatal Error (continued) Table 3-16. Remedies for Fatal Error (continued)
Step Check Point Actions
6 Is the lever
securing the
planetary gear
dislocated from
the frame?
Has the tension
spring come off?
Check if the two
hooks securing
the planetary gear
fixing lever to the
Pump/ASF switch
mechanism are
released from the
frame.
Also, check the
tension spring’s
condition.
7 Has the coil for
the Pump/ASF
motor burnt?
Measure the internal coil resistance of the pump/ASF
motor in the same manner as for the CR motor (Step 4).
<Resistance: 7.0 Ω ± 10%>
8 Is the coil for the
ASF solenoid
burnt?
Referring to the figure below, measure the coil
resistance of the solenoid coil using a tester. Note the
tester can be used regardless of the polarity.
<Resistance: 588 Ω ± 10%>
<P um p/A S F S w itching M echanism >
Pum p/ASF M otor
Lever Fixing the
Planetary G ear
Iron C ore in
t
he Solenoid
Tension Spring
Solenoid
Step Check Point Actions
9 Is the CRHP sensor
defective? Check for the correct voltages at 3-pin connector
shown in the figure below.
Turn the printer on and check the voltage is correct
as follows:
• When the CR has come in the home position, the
voltage rises to 2.4 VDC or higher.
• When the CR has left the home position, the
voltage drops to 0.7 VDC or lower.
10 Is the ASF sensor
defective? Check for the proper voltage in the same manner as
described in the previous step. The ASF connector
(3-pin) location on the relay board is also shown in
the figure above. The pin configuration is also the
same as CRHP sensor.
At power on, the ASF reset operation is performed,
and the ASF Sensor detects ASF home position.
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
To Pin 2 (G N D )
To Pin 3
(CRHP)

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 90
3.1.2 Isolating the Faulty Part on the Power Supply Board
This section explains how to troubleshoot the following problems:
The printer is turned on, but the initialization is not performed and
LED on the control panel do not come on.
Problems after power on
Be sure to perform troubleshooting in the order specified, because the
parts involved are mentioned in the disassembly procedure to facilitate
servicing.
Table 3-17. Isolating the Faulty Part on the Power Supply Board
Table 3-18.
Isolating the Faulty Part on the Power Supply Board (continued)
Step Check Point Action
1 Is the panel FFC
disconnected from the
connector on the panel
board?
The power switch for this printer is in the secondary
side. Therefore, if the FFC does not transfer
signals, the printer does not operate despite the
power supply board and the main board are
properly connected.
2 Is the panel FFC
disconnected from the
connector (black, 12-
pin) on the relay board?
This printer uses the power switch on the
secondary side. Therefore, if the FFC does not
transfer signals, the printer does not operate
despite the power supply board and the main board
are properly connected.
3 Is the connector
disconnected from the
CN15 on the main
board?
The reason is the same as above.
The panel control FFCs are connected via 1) CN15
on the main board → 2) Relay board → 3) Control
Panel.
4 Has the fuse (F1) on
the power supply board
blown?
Check if the line in the F1 located beside the CN1
on the power supply board has blown.
5 Is CN2 or CN3 on the
power supply board
disconnected?
Check that the connectors CN2 and CN3, which
are used to apply power to the main board, are
properly connected.
Step Check Point Action
6 Is CN 5 or CN6 on the
main board
disconnected?
Check that the connectors CN5 and CN6, which
are used to input power from the power supply
board, are properly connected.
7 Is the choke coil
broken? Viewing the reverse side of the power supply
board, check for the proper continuity at the two
points indicated in the figure below.
8 Is the transformer (T1)
broken? Referring to the figure below, check if the
transformer is disconnected between the poles. Try
every combination in each group marked with a
blue box.
L1 (reverse side)
CN1 side CN2 side
CN5 Side CN3 Side
T1
(reverse side)

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 91
Table 3-19.
Isolating the Faulty Part on the Power Supply Board (continued) Table 3-20.
Isolating the Faulty Part on the Power Supply Board (continued)
Step Check Point Action
9 Is the main switching
FET (Q1) defective? Check the electrical continuity of the switching
FET by trying four patterns below. Be sure to pay
attention to the polarity. If the main switching FET
is good, the findings should be as shown under the
figure.
Step 1: Off, Step 2: On, Step 3: Off, Step 4: Off
10 Is the NPN connection
transistor defective? Check the electrical continuity of the NPN
connection transistor on the C265 PSB/SE board
by trying four patterns below. Be sure to pay
attention to the polarity. If the NPN contact
transistor is good, the findings should be as shown
under the figure. Note the NPN connection
transistor is shown in the circuit diagram as
described below.
Step 1: On, Step 2: Off, Step 3: Off, Step 4: On
Step.1
G
D
S
+
-
Step.2
G
D
S
+-
Step.3
G
D
+
-
Step.4
G
D
+
-
Step.1
++
Step.2
+
+
-
NPN Tr
Step.3 Step.4
B
C
E
B
C
E
B
C
E
B
C
E
-
-
-
Step Check Point Action
11 Is the PNP connection
transistor defective? Check the PNP connection transistor on the C265
PSB/SE board in the same manner described in
the previous step.
Step 1: Off, Step 2: On, Step 3: Off, Step 4: On
12 Is the +5 V regulator
(IC51) defective? Check the IC51 for the oscillation waveform
(measured by using a oscillo scope) output from
the Pin 5. If the output waveform is as shown
below, it means the IC51 is working properly.
Step.1
+
-+-
Step.2
+
-+
-
BE
C
PNP Tr
Step.3 Step.4
E
B
C
E
B
C
E
B
C
E
B
C
5-pin(O SC )
GND
IC 5 1
O s c illa tio n w a v e fo rm

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 92
3.1.3 Isolating the Faulty Part according to the Phenomenon
Refer to this section if you could not solve the problem in Section 3.1.1
or Section 3.1.2 or need more information to isolate the cause
according to the exhibited phenomenon. The contents mostly cover the
problems relating to the C265 Main board and their remedies.
Table 3-21. Phenomena Exhibited
Table 3-22. Cooling Fan does not Rotate
No. Phenomenon Exhibited Table to refer to
1 The cooling fan does not rotate.
Note the cooling fan does not constantly rotate.
Refer to Chapter 2 / Section 2.3.7.
Table 3-22,
2 CR motor does not rotate. Table 3-23
3 PF motor does not rotate. Table 3-24
4pump/ASF motor does not rotate. Table 3-25, Table 3-26
5 ASF solenoid does not operate. Table 3-27, Table 3-28
6 Cleaning does not solve the print problem. Table 3-29 - Table 3-33
7 Ink End Error occurs after the printhead is
replaced, so the printhead can not be adjusted. Table 3-34
Step Check Point Action
1 Is the fuse (F6)
open? Place the probes of the tester on the both terminals of
the chip fuse (F6) on the C265 Main board. Then
check for electrical continuity. F6 is located beside the
Q7 which is in front of the cooling fan connector
(CN13).
2 Is the transistor
(Q7) defective? Q7 is beside the connector (CN13 for the cooling fan).
Since the three terminals for the base, emittor, and
collector are not marked, try every pattern below to
check for electrical continuity. Be sure to test with the
correct polarity. The correct findings are shown under
the figure.
Step 1: On, Step 2: Off, Step 3: On, Step 4: Off
3 Is the internal coil
for the fan motor
open?
Replace the Fan unit and then check for the correct
operation.
4 Is the C265 Main
board defective? If the cause has not been isolated yet, replace the
C265 Main board.
Soldered
area
-
+
Step 1 S tep 2
Step 3 Step 4
+
++
-
-
-

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 93
Table 3-23. CR Motor does not Operate Table 3-24. PF Motor does not Operate
Step Check Point Action
1 Getting ready
for inspecting
waveforms.
The connector used to control the CR motor is indicated
in the figure below. Using the oscillo scope, check for the
waveform for each phase at the indicated connector.
To check the waveform, press the Load/Eject button to
attempt to move the carriage. Be sure to leave the cable
for the CR motor connected.
NOTE: The GND can be output by placing the probe of
the oscillo scope to the tapped hole in the
bottom plate on the board with a screw. Note
the connector has no ground line since this
printer drives the motor with the bipolar system.
2 Check of the
waveform and
remedies
While trying to drive
the CR motor, the
waveform output
from each phase
should be as shown
in the figure. If the
waveform output
from each phase is
as shown below,
replace the CR
motor. If not,
replace the IC12 (CR motor driver IC) or C265 Main
board.
NOTE: The GND can be output by placing the probe of
the oscillo scope to the tapped hole in the
bottom plate on the board with a screw.
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
Phase A , Phase B , Phase /A, and
Phase /B from the Pin 1 m ark.
20V 20
µ
Step Check Point Action
1 Getting ready
for inspecting
waveforms.
The connector used to control the PF motor is indicated
in the figure below. Using the oscillo scope, check for the
waveform for each phase output from the indicated
connector. To check the waveform, press the Load/Eject
button to attempt the ASF paper feeding. Be sure to
leave the cable for the PF motor connected.
NOTE: The GND can be output by placing the probe of
the oscillo scope to the tapped hole in the
bottom plate on the board with a screw. Note
the connector has no ground line since this
printer drives the motor with the bipolar system.
2 Check of the
waveform and
remedies.
While trying to drive
the PF motor, the
waveform output from
each phase should be
as shown in the
figure. If the
waveform output from
each phase is as
shown in the figure,
replace the PF motor.
If not, replace the
IC11 (PF motor driver IC) or C265 Main board.
NOTE: The GND can be output by placing the probe of
the oscillo scope to the tapped hole in the
bottom plate on the board with a screw.
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
Phase A, Phase B, Phase /A, Phase /B
from the Pin 1 m ark
20V 20
µ

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 94
Table 3-25. Pump/ASF Motor does not Operate Table 3-26. Pump/ASF Motor does not Operate (continued)
Step Check Point Action
1 Getting ready for
inspecting
waveforms.
The connector used to control the Pump/ASF motor
is indicated in the figure below. Using the oscillo
scope, check the waveform for each phase output
from the indicated connector. To check the
waveform, press the Load/Eject button to attempt
the ASF paper feeding. Be sure to leave the cable
for the Pump/ASF motor connected.
NOTE: The GND can be output by placing the
probe of the oscillo scope to the tapped
hole in the bottom plate on the board with a
screw. Note the connector has no ground
line since this printer drives the motor with
the bipolar system.
M/C
M/C
CRH PE ASF
RED
WHT
BLK
M/C
Phase A, Phase B, Phase /A, Phase /B
from the P in 1 m ark
Step Check Point Action
2 Check of the
waveform and
remedies.
While trying to drive the Pump/ASF motor, the
waveform output from each phase should be as
shown below. If the waveforms output from each
phase are as shown below, replace the Pump/ASF
motor. If not, replace the IC13 (Pump/ASF motor
driver IC) or C265 Main board.
NOTE: The GND can be output by placing the
probe of the oscillo scope to the tapped
hole in the bottom plate on the board with a
screw.
20V
20
20V
20
µ
µ

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 95
Table 3-27. ASF Solenoid does not Operate Table 3-28. ASF Solenoid does not Operate (continued)
Step Check Point Action
1 Is the fuse (F4)
open? Place the probes of the tester on the both terminals of
the chip fuse on the C265 Main board, then check for
electrical continuity. The F4 is located between CN12
and CN16 and also beside the Q9.
2 Is the transistor
(Q8) defective? Place the probe of the oscillo scope on the collector side
of the transistor Q8 on the C265 Main board, then check
that 40 VDC is constantly applied. Then press the Load/
Eject button and check if the voltage drops to 0 VDC for
an instant. If it does, it means the Q8 is working properly.
The Q8 is located between CN12 and CN16.
Q8
20V 20
20V 20
µ
µ
Step Check Point Action
3 Is the transistor
(Q9) defective? Place the probe of the oscillo scope on the emittor side of
the transistor Q9 on the C265 Main board, then check
that voltage is always 0 VDC. Then press the Load/Eject
button and check for an instant change in voltage level
from 0 to 40 VDC. if it changes correctly as described
above, it means the Q9 is working properly. The Q9 is
located beside the CN16.
4 Is the C265
Main board
defective?
If the cause has not been isolated yet in the previous
steps, replace the C265 Main board.
Q9
20V 20
20V 20
+
µ
µ

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 96
Table 3-29. Cleaning does not Solve the Print Problem Table 3-30. Cleaning does not Solve the Print Problem (continued)
Step Check Point Action
1 Repeat the cleaning
7 or 8 times. Unlike the previous products, the Stylus Color 900
is not equipped with the CL3 (dummy cleaning).
Therefore, you can repeat the cleaning every time
you press the Cleaning button without running a
self-test nor any printing.
2 Trying the initial ink
charge operation. You can repeat the initial ink charge operation in
the way described below:
1. Using the exclusive program, reset the initial ink
charge flag in the EEPROM.
2. Turn the printer back on. (Refer to Chapter 5 for
details.)
3 Reinstalling the
printhead FFC. Remove the upper case and check if the FFCs are
properly connected to the CN8 and CN9 on the
C265 Main board. Even though they are not
installed aslant as shown below, disconnect the
FFC once and connect them again, then run a print
check.
NOTE: Before reinstalling the FFCs, be sure to
remove the frame (in red in the figure)
secured to the lower case with two
screws. Otherwise, proper continuity may
not be guaranteed despite the FFCs look
connected without slant.
Fram e
H eat Sink
C heck that the connectors are
not connected aslant.
Step Check Point Action
4 Check the cap for any
foreign matter, dirt, or
damage.
Remove the printer mechanism and release the
carriage lock at the back of the printer
mechanism to move the carriage unit away from
the home position. Then, have a close look at
the cap rubber and check for any problem below.
5 Has the valve cap fallen
off? If a strong impact is applied to the valve cap in
the cap unit, it may fall off. Therefore, check that
the cap is securely attached to the cap unit.
Without this part, ink can not be absorbed.
Foreign m atter
Dust
D am aged area
on the rubber
R ubber part of the cap
Valves
Valve Cap

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 97
Table 3-31. Cleaning does not Solve the Print Problem (continued) Table 3-32. Cleaning does not Solve the Print Problem (continued)
Step Check Point Action
6 Is any ink tube
disconnected from
the cap unit?
Referring to the figure below, check the following
points:
• Connection between two tubes and the bottom of
the cap (Remove the whole cap from the unit to
check the connection.)
• Connection of each tube and the separator.
• Connection of one tube at the bottom of the valve
7 Is the FFC
disconnected from
the printhead
board?
Remove the printhead unit from the carriage unit, and
bring the printhead surface side upward to check that
two FFC is properly connected. Even though no slant
connection nor disconnection is found, disconnect
the FFC once and install them again.
Applying/releasing
the m inus pressure
Left tube
(s e m itra n s p a re n t)
Ink absorption
R ight tube
(w h ite )
CW
CCW
Separator
FFC 2 FFC 1
Step Check Point Action
8 Is the head driver
transistor defective? If you see the C265 Main board from the heat sink
side, the following four power transistors can be
found:
• Q3 and Q4: Outputs the common voltage for the
row A and B (black nozzle rows)
• Q5 and Q6: Outputs the common voltage for the
row C, D, and E (color nozzles)
To check if each pair transistor is working properly,
check the trapezoid waveform at the emittor terminal
of the charging side (Q3 and Q5). Check the
waveform while running a print.
NOTE: Frequency of waveform and voltage level
(p-p) varies if printing is performed through
the driver. Therefore, as long as the
trapezoid waveform is output, the head
driver IC is considered good, and the
printhead must be replaced in that case.
D2082B1382D2082B1382
TH H eat S ink
Q4 Q3 Q6 Q5
Tr for the
black nozzles
Tr for the
color nozzles
BE
+
20V 2
µ
+

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 98
Table 3-33. Cleaning does not Solve the Print Problem (continued) Unlike the previous products, the procedure after head replacement is
precisely specified. Therefore, be sure to follow the steps in Table 3-34
exactly. The background of the procedure is explained after the table.
Table 3-34.
Ink End Error Occurs after Printhead Replacement
Step Check Point Action
9 Is the head driving
pre-driver defective? If a trapezoid waveform is not output in the
previous step, check all the power transistors (Q3 -
Q6) for base waveforms. Like the head transistor
in Step 8, the power transistors also output
trapezoid waveforms, but are input from the pre-
driver side.
If the waveforms are not output correctly, replace
the IC15/16 or C265 Main board. If the waveform is
output correctly, replace the corresponding power
transistor.
TH Heat Sink
Q4 Q3 Q6 Q5
D2082B1382
D2082
B1382
BE
T r fo r th e
black nozzles
T r fo r th e
color nozzles
20V 2
µ
Step Action
1 Turn the printer power off.
2Replace the printhead.
3 Turn the printer back on. (The printer is in No Ink Cartridge
condition.)
4Keep the Load/eject button pressed down for several seconds.
The printer enters the I/C replacement sequence. (The printer
moves to the black ink cartridge replacement position first, then to
the color cartridge replacement position if the Load/Eject button is
pressed.)
5 Input a 21-digit head IC. (Refer to Chapter 4 “Adjustment” for
details.)
6Perform the initial ink charge operations. (Refer to Chapter 4
“Adjustment” for details.)
7 Perform the head angle adjustment. (Refer to Chapter 4
“Adjustment” for details.)
8 Perform the Bi-D adjustment. (Refer to Chapter 4 “Adjustment” for
details.)
9 Perform the Uni-D adjustment. (Refer to Chapter 4 “Adjustment”
for details.)

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 99
Among the steps, if you do not perform Step 1 to Step 4 in the correct
order especially, Ink Cartridge Out error (Ink End error) may occur
whenever you replace the printhead. The background of this problem is
as follows.
1. Since the printhead equipped with this printer is composed of 480
nozzles and driven by 32.4 KHz, the temperature inside the
printhead rises more easily than any other printer. Therefore, the
temperatures inside the printhead and on the printhead board must
be intensely monitored to avoid damaging the printhead.
2. Rise in the internal temperature of the printhead can cause a fatal
damage to the printhead itself. Heat inside the printhead is normally
removed as the ink flows inside the printhead.
3. If any of the following conditions occurs, the printhead fails to eject
ink properly even though the print data is input.
The printhead surface is left away from the home position for a
long period of time.
The same ink cartridge is remove and installed repeatedly.
The table with the printer on it is moved up and down (vertically)
intensely.
4. If the ink does not flow properly, the PZT gradually heats up and is
eventually hot enough to evaporate the ink inside the cavity (a tank
which stores ink).
5. To prevent the printhead from heating up, the 5-channel abnormal
temperature detection circuit is included in the nozzle selector
(directly attached onto the printhead board). With this circuit, the
temperature of each nozzle row (five rows in total) can be
independently monitored. (Refer to Chapter 2 / Section 2.3.2.)
6. Once the abnormal temperature detection circuit is active, the
printer stops printing and starts a forcible cleaning. This operation
cleans the clogged nozzles, and the ink inside the printhead flow
properly as a result. At this point, the printer sets the flag in the
address for the abnormal temperature detection circuit in the
EEPROM to record the first abnormal temperature error.
7. The printer resumes printing with the data transferred.
8. If the printer detects an abnormally high temperature again, the
printer regards it as the second abnormal temperature error and
enters Ink End Error condition. The printer makes this judgement to
avoid following two problems:
Since the I/C has been repeatedly removed and reinstalled, the
printer fails to evaluate the remaining ink level properly and
leaves the I/C in an empty condition.
Since the I/C has been repeatedly removed and reinstalled, the
ink inside gets stale and can not absorb bubbles and viscous ink
into itself.
9. specifically, the nozzle selectors (5 rows in total) used in the mass
produced Stylus Color 900 are purchased from either of the
following two vendors: EPSON or Sharp. Their ICs slightly differ in
the feed back voltage. Therefore, if the installed printhead has the
nozzle selector and the 1st digit of the printhead ID in the
combination shown in Table 3-35, the printer shows the error at
power on and begins a cleaning automatically. Therefore, even
though the printer continues to print, it forcibly enters the Ink End
error condition for the second time since the flag is already set in the
EEPROM address for the abnormal temperature detection circuit.

EPSON Stylus Color 900 Revision C
Troubleshooting Overview 100
Table 3-35. Combination which Causes the Error
For this reason, if you perform the operation in an incorrect
procedure such as; Head replacement → I/C replacement → Turning
on the printer, the printer starts monitoring the temperatures before
the printhead ID on the board is replaced with a new one, then
shows the error consequently. On the other hand, if you follow the
proper steps; Head replacement → Turning on the printer → proper
I/C replacement with a new one, the program allows a data transfer
once before printing so you can overwrite the printhead ID.
Nozzle Selector 1st digit of the Head ID
The board is in the Sharp-
specific setting. 0
EPSON exclusive printhead 1

DISASSEMBLY AND ASSEMBLY

EPSON Stylus Color 900 Revision C
Disassembly and Assembly Overview 102
4.1 Overview
This chapter describes procedures for disassembling the main
components of EPSON Stylus Color 900. Unless otherwise specified,
disassembly units or components can be reassembled by reversing the
disassembly procedure. Therefore, no assembly procedures are
included in this chapter. Precautions for any disassembly or assembly
procedure are described under the heading “CHECK POINT”. Any
adjustments required after disassembling the units are described under
the heading “REQUIRED ADJUSTMENT”.
4.1.1 Precautions for Disassembling the Printer
See the precautions given under the heading “WARNING” and
“CAUTION” in the right column and the following page, respectively,
when disassembling or assembling EPSON Stylus Color 900.
W ARNING
Disconnect the power cable before disassembling or
assembling the printer.
Wear protective goggles to protect your eyes from
ink. If ink gets in your eye, flush the eye with fresh
water and see a doctor immediately.
If ink comes into contact with your skin, wash it off
with soap and water. If irritation occurs, contact a
physician.
A lithium battery is installed on the main board of this
printer. Be sure to observe the following instructions
when serving the battery:
Keep the battery away from any metal or other
batteries so that electrodes of the opposite polarity do
not come in contact with each other.
Do not heat the battery or put it near fire.
Do not solder on any part of the battery. (Doing so may
result in leakage of electrolyte from the battery,
burning or explosion.) The leakage may affect other
devices close to the battery.)
Do not charge the battery. (An explosive may be
generated inside the battery, and cause burning or
explosion.)
Do not dismantle the battery. (The gas inside the
battery may hurt your throat. Leakage, burning or
explosion may also result.)
Do not install the battery in the wrong direction. (This
may cause burning or explosion.)

EPSON Stylus Color 900 Revision C
Disassembly and Assembly Overview 103
CAUTION
Danger of explosion if the battery is incorrectly
replaced. Replace only with the same or equivalent
type recommended by the manufacturer. Dispose of
used batteries according to government laws and
regulations.
CAUTION
Risque d’explosion si la pile est remplacée
incorrectment. Ne remplacer que par une pile du même
type ou d’un type équivalent recommandé par le
fabricant. Eliminer les piles déchargées selon les lois
et les règles de sécurité en vigueur.
CAUTION
Never remove the ink cartridge from the carriage
unless the manual specifies to do so.
When transporting the printer after the ink cartridge
has been installed, be sure to pack the printer for
transport without removing the ink cartridge.
Use only recommended tools for disassembling,
assembling or adjusting the printer.
Apply lubricants and adhesives as specified. (See
Chapter 6 for details.)
Make adjustments specified when you disassemble
the printer. (See Chapter 4 for details.)

EPSON Stylus Color 900 Revision C
Disassembly and Assembly Disassembly Procedures 104
4.2 Disassembly Procedures
The flowchart below shows procedures for disassembly.
Figure 4-1. Disassembly Flowchart
C 265 M ain B oard R em oval
R elay Board / C ooling Fan R em oval
ASF Rem oval A S F D isassem bly
ASF Sensor Rem oval
Shield Plate on the C 265 M ain
Board R em oval
START
U pper C ase/C ontrol Panel R em oval
Printer M echanism R em oval
Printhead R em oval
PF Motor Removal
Pum p/ASF M otor &
Solenoid R em oval
CRHP Sensor Removal
PE Sensor R em oval
Encoder B elt R em oval
Carriage Unit Rem oval
Pum p Unit Rem oval
Front Fram e R em oval
Paper E ject R oller R em oval
Platen R em oval
PF Roller Rem oval
C265 PSB/PSE Rem oval
CR Motor Rem oval

EPSON Stylus Color 900 Revision C
Disassembly and Assembly Disassembly Procedures 105
Table 4-1.
Removed/Replaced Parts and Corresponding Adjustments
CAUTION
If you have replaced specified parts, you must make
necessary adjustments. See the following tables
which shows the parts removed/replaced and
corresponding adjustments required, and perform
adjustments in the correct order. (See Chapter 5
“Adjsutment” for detailed procedures.)
Actions taken Step Corresponding adjustment required
Printhead 1 Install a new I/C in the I/C replacement sequence.
2 Head Actuator Voltage ID Input
3 Ink Charge Flag Reset
4 Head Angular Adjustment.
5 Bi-Directional Adjustment
C265 Main board 1 Head Actuator Voltage ID Input
2 Bi-Directional Adjustment
CR shaft 1 Remove the Printhead and CR Unit.
2 Remove the oil pad. (Refer to Chapter 6.)
3Clean and lubricate the carriage guide shaft.
4 Reinstall the printhead and the CR Unit.
5Perform the Parallelism adjustment.
6 Enter the I/C replacement sequence to install a new I/C
and make sure it is completed.
7Ink Charge Flag Reset
8Head Angular Adjustment
9Bi-Directional Adjustment
Waste Ink Pad 1 Clear the protection counter value
CR Motor 1 Bi-Directional Adjustment
Program ROM
replacement 1 Head Actuator Voltage ID Input
2 Bi-Directional Adjustment

EPSON Stylus Color 900 Revision C
Disassembly and Assembly Disassembly Procedures 106
4.2.1 Upper Case and Control Panel Removal
1. Remove the sheet guide.
2. Open the upper case.
3. Open the output tray.
Figure 4-2. Upper Case Removal
4. Remove one screw securing the front case (on the left) to the printer
mechanism, then pull the front case forward and remove it from the
printer.
5. Pull the output tray to the left and remove it.
6. Remove two screws securing the control panel to the printer
mechanism to release the control panel. Then disconnect the FFC
fro