Epsonlx 800technicalmanual

LX-HOO
TECHNICAL MANUAL
— .—
EPSON

EPSON is a registered trademark of SEIKO EPSON CORPORATION.
IBM is a registered trademark of International Business Machines Corporation.
NOTICE
‘ All rights reserved. Reproduction of any part of this manual in any form
whatsoever without SEIKO EPSON’s express, written permission is forbidden.
q The contents of this manual are subject to change without notice.
q All efforts have been made to ensure the accuracy of the contents of this manual.
However, should any errors be detected, SEIKO EPSON would greatly appreciate
being informed of them.
q The above notwithstanding, SEIKO EPSON can assume no responsibility for any
errors in this manual or their consequences.
@ Copyright 1987 by SEIKO EPSON CORPORATION
Nagano, Japan
-i-

REV.-A
PRECAUTIONS
Precautionary notations throughout the text are categorized relative to: 1 ) personal injury, and 2) damage
to equipment.
DANGER Signals a precaution which, if ignored, could result in serious or fatal personal injury.
Great caution should be exercised in performing procedures preceded by DANGER
headings.
WARNING Signals a precaution which, if ignored, could result in damage to equipment.
The precautionary measures itemized below should always be observed when performing repair/main-
tenance procedures.
DANGER
1. ALWAYS DISCONNECT THE PRODUCT FROM BOTH THE POWER SOURCE AND THE
HOST COMPUTER BEFORE PERFORMING ANY MAINTENANCE OR REPAIR
PROCEDURE.
2. NO WORK SHOULD BE PERFORMED ON THE UNIT BY PERSONS UNFAMILIAR WITH
BASIC SAFETY MEASURES AS DICTATED FOR ALL ELECTRONICS TECHNICIANS IN
THEIR LINE OF WORK.
3. WHEN PERFORMING TESTING AS DICTATED WITHIN THIS MANUAL, DO NOT
CONNECT THE UNIT TO A POWER SOURCE UNTIL INSTRUCTED TO DO SO. WHEN
THE POWER SUPPLY CABLE MUST BE CONNECTED, USE EXTREME CAUTION IN
WORKING ON POWER SUPPLY AND OTHER ELECTRONIC COMPONENTS.
WARNING
1. REPAIRS ON EPSON PRODUCT SHOULD BE PERFORMED ONLY BY AN EPSON-CERTl-
FIED REPAIR TECHNICIAN.
2. MAKE CERTAIN THAT THE SOURCE VOLTAGE IS THE SAME AS THE RATED
VOLTAGE, LISTED ON THE SERIAL NUMBER/RATING PLATE. IF THE EPSON
PRODUCT HAS A PRIMARY AC RATING DIFFERENT FROM THE AVAILABLE POWER
SOURCE, DO NOT CONNECT IT TO THE POWER SOURCE.
3. ALWAYS VERIFY THATTHE 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 /.LP CHIPS AND CIRCUITRY, USE STATIC
DISCHARGE EQUIPMENT, SUCH AS ANTI-STATIC WRIST STRAPS, WHEN ACCESS-
ING INTERNAL COMPONENTS.
5. REPLACE MALFUNCTIONING COMPONENTS ONLY WITH THOSE COMPONENTS
RECOMMENDED BY THE MANUFACTURER; INTRODUCTION OF SECOND-SOURCE
ICS OR OTHER NONAPPROVED COMPONENTS MAY DAMAGE THE PRODUCT AND
VOID ANY APPLICABLE EPSON WARRANTY.
- ii -

REV.-A
PREFACE
This manual describes functions, theory of electrical and mechanical opera-
tions, maintenance, and repair of the LX-800.
The instructions and procedures included in this document are intended for
the experienced repair technician, who should pay attention to the precautions
on the preceding page. The chapters are organized as follows:
Chapter 1 —
—
Chapter 2 —
Chapter 3 —
Chapter 4 —
Chapter 5 —
Chapter 6 —
Provides a general product overview, lists specifications, and
illustrates the main components of the printer
Describes the theory of printer operation
Discusses the options
Includes a step-by-step guide for product disassembly, assem-
bly, and adjustment
Provides Epson-approved techniques for troubleshooting
Describes preventive maintenance techniques and lists lubri-
cants and adhesives required to service the equipment
q The contents of this manual are subject to change without notice.
- iv -

I
REVISION SHEET
REVISION I DATE ISSUED CHANGE DOCUMENT
1st issue
1-1, 5, 8, 12 through 18
2-2,11, 13,28,30,38 through
42
4-1, 13, 17, 19
5-1, 2, 6
6-1
A-2, 17, 18
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REV.-A
TABLE OF CONTENTS
CHAPTER 1. GENERAL DESCRIPTION
CHAPTER 2. OPERATING PRINCIPLES
CHAPTER 3. OPTIONAL EQUIPMENT
CHAPTER 4. DISASSEMBLY, ASSEMBLY, AND ADJUSTMENT
CHAPTER 5. TROUBLESHOOTING
CHAPTER 6. MAINTENANCE
APPENDIX
- vi -

REV.-A
—. —
1.1
1.2
1.3
1.4
1.5
CHAPTER 1
GENERAL DESCRIPTION
FEATURES .................................................................................................1-1
INTERFACE ...............................................................................................1-3
SPECIFICATIONS ....................................................................................1-6
OPERATING CONTROLS .....................................................................1-12
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
Dip Switch and Jumper Settings ..........................................1-12
Control Panel (and Auto Sheet Load Function) . . . . . . . . . . . . . . . . 1-14
Self Test and Hexadecimal Dump Functions . . . . . . . . . . . . . . . . . . . . 1-15
SeiecType Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-16—.
Buzzer and Error Functions ......................................................1-17
Printer Initialization and Default Values ............................ 1-17
MAIN COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
1.5.1
1.5.2
1.5.3
1.5.4
1.5.5
Fig. 1-1.
Fig. 1-2.
Fig. 1-3.
Fig. 1-4.
Fig. 1-5.
Fig. 1-6.
Fig. 1-7.
Fig. 1-8.
Fig. 1-9.
Fig. 1-10.
Fig. 1-11.
Printer Mechanism Model-3A10 ............................................1-18
ROC Filter Unit.............................................................................1-19
ROCX Board Unit ........................................................................1-20
LCPNL Board Unit.......................................................................1-20
Housing ...........................................................................................1-21
LIST OF FIGURES
Exterior View of
Exterior View of
LX-800 ...........................................................1-1
LX-800 with Tractor Unit. . . . . . . . . . . . . . . . . . . . . . . 1-2
Data Transmission Timing of 8-Bit Parallel Interface.... 1-3
57-30360 36-Pin Connector ....................................................1-3
Printhead Pin Configuration ...................................................1-6
Printable Area for Cut Sheet Paper ..................................... 1-9
Printable Area for Roll Paper..................................................1-9
Printable Area for Fan Fold Paper ........................................ 1-1o
Control Panel ................................................................................1-14
SelecType Flow Chart ...............................................................1-16
Mode13Al O Printer Mechanism .............................................1-18
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REV.-A
Fig. 1-12. ROC Filter Unit (120V Version) ..............................................1-19
Fig. 1-13. ROC Filter Unit (220V/240V Versions) ............................... 1-20
Fig. 1-14. ROCX Board Unit ........................................................................1-20
Fig. 1-15. LCPNL Board Unit.......................................................................1-20
Fig. 1-16. Housing ...........................................................................................1-21
LIST OF TABLES
Table 1-1. LX-800 Options ...........................................................................1-2
Table 1-2. Connector Pin Assignments and Signal Functions . . . . . . . . 1-4
Table 1-3. Printer Select/Deselect (DC1/DC3) Control . . . . . . . . . . . . . . . . . . . . . 1-5
Table 1-4. Printer Speed, Character Size, and Column Width . . . . . . . . 1-7
Table 1-5. Type of Paper ..............................................................................1-8
Table 1-6. DIP Switch Settings .................................................................1-12
Table 1-7. International Character Set ...................................................1-13
Table 1-8. DIP Switches Factory Settings ............................................. 1-13
Table 1-9. Jumper Setting ...........................................................................1-13
I i i

REV.-B
1.1 FEATURES
The LX-800 is a multifunctional and high speed serial dot impact printer with a compact body and the
low price.
Features include:
q
q
q
q
q
q
q
q
q
q
180 cps maximum speed (draft-elite), 150 cps (draft-pica)
Upward compatibility with the LX-86
Built in two NLQ fonts (Roman and Saris-serif)
Direct selection of NLQ/Draft modes, and easy selection of 4 typestyle modes with SelecType controls
Built in IBM graphics characters
Super/Subscript, Italics, and Elite modes can be supported in NLQ
Automatic sheet loading function
A 3K-byte input buffer for improved throughput from the host computer
Pull tractor feeding
Optional interface for the EPSON #81 XX series
Tw=models of the LX-800 are manufactured. The model for t~e U.S and Australia uses printer cover
A and the model for all countries except the U.S. and Australia uses printer cover B.
Figures 1-1 and 1-2 show the external view of the LX-800. Table 1-1 lists the options.
(Printer cover A)
Fig. 1-1. Exterior
(Printer cover B)
View of LX-800
1-1

REV.-A
(Printer Cover A)
Fig. 1-2. Exterior View of
(Printer Cover B)
LX-800 with Tractor Unit
Table 1-1. LX-800 Options
I Option No. I Description
#83 1 0
#81 33
#8 143
#8 145
#81 48
#8 165
Roll Paper Holder
APPLE II Intelligent Interface
New Serial Interface
RS-232C/Current Loop Type 2 InterFace
Intelligent Serial Interface
Intelligent IEEE-488 Interface
1-2

REV.-A
1.2 INTERFACE
The LX-800 has a 8-bit parallel interface as a standard. The specifications for the 8-bit parallel interface
are as follows:
Data Format:
Synchronization:
Hand Shaking:
Logic Level:
Data transmission
Connector:
BUSY
ACKNLG
OATA
STROBE
8-bit parallel
By STROBE pulse
By both ACKNLG and BUSY, or either of them
ITL (LS type) compatible
timing: See Figure 1-3.
57-30360 (AMPHENOL) or equivalent (See Figure 1-4.)
0.5JAS 1= 0.5JAS O..sus
min. min. min.
NOTE: Transmission time (rising and falling time)
“w
Fig. 1-3. Data Transmission Timing
of every input signal must be less than 0.2Ks.
for 8-Bit Parallel Interface
1. 19. GNO ( Pair with 1.)
2. 20. GNO ( Pair w;tn2.)
3. Z 1. GNO ( Pair w;th3.)
4. 22. GNO ( Pair wnh4.)
5. 23. GNO ( Pair w;tn5.)
6 . 24. GNO ( Pair w;th6.)
7. 25. GNO ( Pair witn7.)
e. 2 6 . GNO ( Pair w;th S.)
9 . 27. GNO ( Pair w;tn9.)
10 2S. GNO ( Pair w:th 1 0 . )
11 29. GND ( Pair with 11. )
12 3 0 . GNO ( Pair witn 12.)
1 3 3 1 . m
14 3 2 . m
15 3 3 . GNO
16 3 4 . N C
17 3 5 . +5V
18 3 6 . m
Fig.1-4. 57-30360 36-Pin Connector
1-3

REV.-A
Table 1-2 shows the connector pin assignments and signal functions of the 8-bit parallel interface.
Table 1-2. Connector Pin Assignments and Signal Functions
~in No. Signal Name Return Pin No. DIR Functional Description
1 STROBE 19 In Strobe pulse to read the input data. Pulse width
must be more than 0.51Js. Input data is latched after
falling edge of this signal.
2 DATA 1 20 In Parallel input data to the printer.
3 DATA2 21 In “HIGH” level means data “ 1“.
4 DATA3 22 In “LOW” level means data “O”.
5 DATA4 23 In
6 DATA5 24 In
7 DATA6 25 In
8 DATA7 26 In
9 DATA8 27 In
10 ACKNLG 28 out This pulse indicates data are received and the
printer is ready to accept next data.
Pulse width is approx. 12 KS.
11 BUSY 29 out HIGH indicates printer can not accept next data.
12 PE 30 out HIGH indicates paper-out. This signal is effective
only when ERROR signal is “LOW”.
13 SLCT — out Always “HIGH” output. (Pulled up to +5V through
3.3 K ohms register.)
14 AUTOFEED-XT — In If the signal is “LOW” when the printer is initialized,
a line feed is automatically performed by input of
“CR” code. (Auto LF)
15 — — — Not used.
16 GND — — Ground for twisted-pair grounding.
17 Chassis GND — — Chassis ground level of printer
18 — — — Not used.
9 to 30 GND — — Ground for twisted-pair grounding.
31 I NIT 16 In Pulse (width: 50MS min., active “LOW”) input for
printer initialization.
32 ERROR — out LOW indicates that some error has occurred in the
printer.
33 GND — . Ground for twisted-pair grounding
34 — — — Not used.
35 — — out Always “HIGH”. (Pulled up to +5V through a
3.3k-ohm register.)
36 SLCT-IN — In If the signal is “LOW” when printer is initialized, the
DC l/DC3 control is disabled.
1-4

REV.-B
NOTES 1. “Return” denotes a twisted pair return line connected to signal ground. When interfacing
the printer to the host, use twisted pairs for each signal. Shield the twisted pairs, and connect
the shield to GND in order to reduce interface.
2. All interface conditions are based on TTL levels. Both the rise and fall times of all signals
must be less than 0.2Ks.
3. Refer to the Parallel Interface Timing Chart for the timing of the signals.
4. Data transfer protocol must not ignore the ACKNLG or BUSY signal. (Data can be transferred
either after recognizing the ACKNLG signal or when the BUSY signal is LOW.)
5. The AUTO FEED XT and SLCT IN signals are valid when they are not fixed to LOW level by
the DIP switch or jumper.
6. Printing tests, including those of the interface circuits, can be performed without using
external equipment: set interface connector data lines 1-8 to the desired code (a floating
signal will be a logical 1, and a grounded signal will be a O) connect the ACKNLG signal
to the STROBE signal.
7. The PE signal is valid when the ERROR signal is LOW.
— Table 1-3. Printer Select/Deselect (DC—1/DC3) Control
SLCT IN Signal State Printer
Dcl/Dc3
at Initialization Select/Deselect
Data entry
I DC 1 I Select I Enable
HIGH DC3 Deselect Enable (Waits for a DC1. Input data is ig-
nored until a DC 1 code is received.)
DC1 Select Enable
LOW
DC3 Select Enable
1-5

REV.-A
1.3 SPECIFICATIONS
This chapter describes the specifications of the LX-800 printer.
q General Specifications
Printing method:
Pin configuration:
Pin diameter:
Dot Pinch:
Printing direction:
Text mode:
Bit-image mode:
Dot matrix:
Character sets:
Fonts:
Printing speed:
Character size:
Column width:
Serial impact dot matrix
9 wires (see Figure 1-5)
0.29 mm
0.35 mm (1/72 inch)
#1
#2
#3
# 4
# 5
# 6
# 7
# 8
# 9
() i
() 0.29mm
t
<>
0.35mm (1 /72”)
t
( )
Fig. 1-5. Printhead Pin Configuration
Bi-directional with logic seeking
Uni-directional (left to right)
9 X 9 (Draft)
11 X 18 (NQL)
6 X 8 (Graphics)
96 ASCII characters
96 Italic characters
32 International characters
32 International Italic characters
32 Graphics characters
96 IBM Graphics characters
Draft, NLQ-Roman, Saris-serif
See Table 1-4
See Table 1-4
See Table 1-4
480 dots/line at 60 dots/inch (Bit-image)
1-6
—.—

REV.-A
Table 1-4. Printing Speed, Character Size, and Column Width
Type Style Charecter Size (mm) Column Width Pitch (meximum
Font Normal Double Empha- Con- Printing Speed (CPS) Width
(maximum Chara- Characters
Width sized densed
Height cters/LinsCPL) /inch-CPl)
Draft 0 — — — 150 2.1 3.1 80 10
(Pica) o — — 75 4.2 3.1 40 5
— . 0 — 75 2.1 3.1 80 10
0 0 — 37 4.2 3.1 40 5
— — — o 128 1.05 3.1 132 17
0 — o 64 2.1 3.1 66 8.5
Draft o — — — 180 2.1 3.1 96 12
(Elite) — o — — 90 4.2 3.1 48 6
— — — o 150 1.05 3.1 160 20
NLQ o — — — 25
Super-
sub- 0 — — — 1.6
script
...—
Line spacing: 1/6” or Programmable (n/2 16“)
Line feed speed: Approx. 95ms/line (Line feed)
(1 line = 1/6”) Approx. 75ms/line (Form feed)
Paper feed method: Friction feed or Tractor feed
Paper path: From rear of printer
q Paper Specifications
Type of paper: See Table 1-5
1-7

REV.-B
Table 1-5. Type of Paper
Cut sheet Fan-fold paper Roll paper
Size (Width) (Width) (Width)
182 mm to 216 mm 101 mm to 254 mm 216 & 3 mm
7. 15“ to 8.5” 4“ to 10” 8.5” & 0.12“
(Length) (Diameter of roll)
Max. 305 mm Max. 127 mm
Max. 12“ Max. 5“
Thickness 0.06 mm to 0.1 mm Max. 0.25 mm 0.07 mm to 0.09 mm
Copies 1 original +2
Weight 52g/m2 to 82g/m2 (1 sheet) 52g/m2 to 64g/m2
52g/m2 to 82g/m2
(2 sheets)
35g/m2 to 58g/m2
(3 sheets)
35g/m2 to 58g/m2
for 2 sheets
+
35g/m2 to 47g/m2
for 1 sheet
Feeding method Friction feed Tractor feed Friction feed
Precautions 1. Do not use continuous 1. Release the friction 1. Use the Roll paper
form or copy paper. mechanism using the holder.
2. Dismount the Tractor release lever. 2. Dismount the Tractor
unit. 2. Use the pressure sen- unit.
sitive paper for copy-
ing. Be sure that per-
forations have a smooth
finsh.
1-8

Printable area:
REV.-A
See Figures 1-6 through 1-8
—
0.1 2“, 3 g
or more
T0.87”, :
or n
1
7
1 2“”,
305 mm
L1 .2’.
or mor
m
F
r
i
n
t
a
b
t
e
a
r
e
a
, 3 (
7.1 5“ - 8.50/182 mm - 216 mm
I-
Printable area I
I I
mm
TABC
T
XYZ
.—
LABC JXYZ
lm
Fig. 1-6. Printable Area for Cut Sheet Paper
0.1 2“/3 mm–
or more
0.98”/25 mm
or more !
8.5”, 216 mm q
Printable area
ABC XYZ
0.1 2“, 3 mm
=more
0.1 2“/3 mm
‘or more
Fig. 1-7. Printable Area for Roll Paper
1-9

REV.-A
4“ - 10 ”/101 mm - 254 mm
L Printable area R
7
Printable
area
/
0.35 ”/9 mm
or more
4
0.35 ”/9 mm
or more
i
Printabh
area
o
0
0
0
0
0
0
1-0 ABC
o
0
0
0
0
0
0
1XYZ :o
0 0
0 0
- - - - - - - - - - - - - - - - - - - - - - - - - - -
0 0
0 0
0
To ABC
7
XYZ :
o 0
0 0
0 0
0 0
0 0
0 0
0 0
L: 0.75”/19 mm [PaDer width is less than 9.5”/241 mm)
1.02”)26 mm ~Paper width is more than 9.5 ”/241 mm)
R: 0.75”/19 mm (Paper width is less than 9.5 ”/241 mm)
0.94”/24 mm (Paper width is more than 9.5 ”/241 mm)
Fig. 1-8. Printable Area for Fan Fold Paper
Ribbon Cartridge
Cartridge number: # 8 7 5 0
Color: Black
Life: 3 million characters (14 dots/character)
Electrical Specifications
Power Voltage:
Frequency range:
Power consumption:
Insulating resistance:
Dielectric strength:
120VAC + 10%
220/240VAC * 10%
59.5Hz to 60.5Hz (120VAC)
49.5Hz to 60.5Hz (220/240VAC)
Max. 70VA
More than 10M ohms
(between the AC line and chassis)
1 KVAC rms/minute or 1.2KVAC rms/second
between AC line and chassis (120V)
1.25 kVAC rms/minute or 1.5 kVAC rms/second
between AC line and chassis (220/240V)
1-1o

REV.-A
q Environmental Specifications
Temperature: –30”C to 60 ”C/–22°F to 149°F (Storage)
5°C to 35”C/4 1“F to 95°F (Operating)
Humidity: 5% to 85%RH, no condensation (Storage)
10% to 80%RH, no condensation (Operating)
Resistance to shock: 2G, 1 ms (Storage)
IG, 1 ms (Operating)
Resistance to vibration: 0.50G, max. 55Hz (Storage)
0.25G, max 55Hz (Operating)
q Reliability
MCBF:
MTBF:
Life of printhead:
q Safety Approvals
. safety Standards:
RFI:
q Physical
Dimensions:
(Refer to Figure A-19)
Weight:
3 million lines (Printer mechanism except the printhead)
4000 hours
200 million strokes/needle
UL 478 (U. S.A.) —
CSA 22.2 No. 0.154 (Canada)
VDE 0806 (West Germany)
FCC class B (U. S.A.)
VDE 0871 (West Germany)
91 mm (height)
377 mm (width)
399 mm (width including paper feed knob)
308 mm (depth)
5.1 kg
1-11

REV.-B
1.4 OPERATING CONTROLS
This section describes the operating controls of LX-800 printer.
1.4.1 DIP Switch and Jumper Settings
The DIP switches that users can set are SW1 and SW2. These switches are positioned at the rear center
of the printer and have the functions shown in Tables 1-6 through 1-8. (Note: the status of the DIP
switches is read only when at power on or at input of the INIT signal).
Table 1-6. DIP Switch Settings
DIP SW Function ON OFF
1-1 Typeface select Condensed Normal
1-2 ZERO font select 0 0
1-3 Character Table select I Graphic I Italic
1-4 I Paper-out detection I Valid I invalid
1-5 I Printing quality select I NLQ I Draft
1-6
1-7 International character set select See Table 1-7
1-8
2-1 Page length select 12“ 1 1“
2-2 Cut sheet feeder mode Valid Invalid
2-3 1“ skip over perforation Valid Invalid
2-4 AUTO FEED XT control Fix to LOW Depends on ex-
ternal signal
1-12

REV.-B
Table 1-7. International Character Set
?-
Country SW 1-6 Sw 1-7 SW 1-8
U.S.A. ON ON ON
FRANCE ON ON OFF
GERMANY ON OFF ON
U.K. ON OFF OFF
DENMARK OFF ON ON
SWEDEN I OFF I ON I OFF I
ITALY OFF OFF ON
SPAIN OFF OFF OFF
Table 1-8. DIP Switches Factory Settings
DIP SW No.
1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 2-1 2-2 2-3 2-4
Country
U. S.A., Southeast Asia,
OFF OFF OFF OFF OFF ON ON ON OFF OFF OFF OFF
Middle and Near East
Germany, OFF OFF OFF OFF OFF ON OFF ON ON OFF OFF OFF
Northern Europe
U. K., Australia OFF OFF OFF OFF OFF ON OFF OFF OFF OFF OFF OFF
France, Italy, Spain OFF OFF ON OFF OFF ON ON ON OFF OFF OFF OFF
Jumper J 1 on the ROCX board has the function and factory setting shown in Table 1-9.
Table 1-9. Jumper Setting
Jumper Function Open Close Factory setting
J1 SLCT IN control Depends on external signal Fix to LOW Open
1-13

REV.-B
1.4.2 Control Panel (and Auto Sheet Load Function)
Figure 1-9 shows the control panel of LX-800 printer.
a
b
c
d
e
f
9
Fig. 1-9. Control Panel
The functions of the LEDs and switches are:
a.
b.
c.
d.
e.
f,
POWER LED (green)
Lights when the power switch is turned on and AC power is applied.
READY LED (green)
Lights when the printer is ready to receive data.
PAPER OUT LED (red)
Lights when the printer runs out of paper.
ON LINE LED (green)
Lights when the printer is ON-LINE.
ON/OFF LINE Switch (non-locking push switch)
Switches between the ON-LINE and OFF-LINE modes.
The printer is automatically set ON-LINE and becomes ready when power is turned on. If the printer
is set OFF-LINE, printing is stopped and the printer enters the busy state.
NLQ/FORM FEED Switch (non-locking push switch)
q
q
When this switch is pressed once in the OFF-LINE mode, the paper is advanced vertically to the
top of form on the next page.
When this switch is pressed in the ON-LINE mode, the NLQ-Roman or NLQ-Sans-serif fonts are
selected, and the buzzer sounds to inform the user which font is selected.
NLQ-Roman: Two beeps
NLQ-Sans-serif: Three beeps
1-14

REV.-B
g. DRAFT/LINE FEED and AUTO LOAD Switch (non-locking push switch)
q
q
q
When this switch is pressed once in the OFF-LINE mode, the paper is advanced vertically one line,
and the paper advanced continuously while this switch is pressed.
When this switch is pressed in the ON-LINE mode, the Draft font is selected, and beeps once a
buzzer to inform the Draft font is selected.
Cut sheets are automatically loaded when the paper is placed at the sheet guide, printer is paper
out, OFF-LINE state and the this switch is pressed.
1.4.3 Self Test and Hexadecimal Dump Functions
The conditions of LX-800 may be checked via the self test functions. The self test checked:
q Circuit
q Printer mechanism
q Printing quality
q ROM (firmware) code number
The code number of ROM is printed on the first line of the self test.
To start the self test in either the Draft mode or NLQ mode,+urn the power on while pressing the
DRAFT/LINE FEED or NLQ/FORM FEED switch, respectively. In the NLQ self test mode, both Roman font
and Saris-serif font are printed every other line. When the DIP switch 1-5 set to on (NLQ mode), only
NLQ mode self test is performed, no related switches. To stop the self test, turn the power off by power
switch.
The conditions of data transmission between LX-800 and the host computer may be checkedvia
hexadecimal dump functions. To set the hexadecimal dump mode, turn the power while pressing
both LINE FEED and FORM FEED switches. Then the message “Data Dump Mode” is printed.
the
the
The printer prints 16 hexadecimal values, followed by the corresponding ASCII characters. If there is
no corresponding printable characters for a value (e.g. a control code), a period (.) is printed. One line
is printed for each set of 16 values received, and any remaining data (less than 16 values) can be printed
by pushing the ON/OFF LINE switch.
To cancel the hexadecimal dump mode, turn the power off by power switch.
1-15

REV.-B
1.4.4 SelecType Function
SelecType is a feature of the LX-800 which permits type style programming via the control panel
switches without software assistance.
In the SelecType mode,
q Emphasized
q Double-strike
q Condensed
q Elite
following 4 type styles can be selected:
Figure 1-10 shows the operation flow chart of SelecType function:
< ENTER >
Hold down ON/OFF LINE SW, and
press NLQ/FORM FEED SW. (Print-
er beeps once and ON-LINE LED
starts blinking.)
I < Select the type style >
I
Press ONOFF LINE SW the number of times indicat-
ed below for the mode. (Pay attention to the number
of beeps the printer makes when the buzzer sounds.)
1 Emphasized 3 Condensed
I 2 I Double-striked I 4 I Elite I
I
< Set type style >
Press FORM FEED SW.
N
]Y
< EXIT >
I Press LINE FEED SW. I
I
I OFF-LINE I
Fig. 1-10. SelecType Flow Chart
1-16

REV.-B
1.4.5 Buzzer and Error Functions
The buzzer rings under the following circumstances:
q
q
q
q
q
q
q
q
When a BEL code is sent to the printer, the buzzer
rings once (for 0.1 sec.).
When the NLQ Roman font is set using the FORM FEED switch, the buzzer
rings twice (for 0.1 sec. each, with 0.1 sec. pause between rings).
When the NLQ Saris serif font is set using the NLQ/FORM FEED switch, the buzzer
rings three times (for O. 1 sec. each, with O. 1 sec. pause between rings).
When the Draft font is set using the DRAFT/LINE FEED switch, the buzzer
rings once (for O. 1 sec.).
When the printer enters the SelecType mode, the buzzer
rings once (for O. 1 sec.).
When paper out is detected, the buzzer
rings eight times (for 0.5 sec. each, with 0.5 sec. pause between rings).
When abnormal carriage operation is detected (hardware error), the buzzer
rings five times (for 0.5 sec. each, with 0.5 sec. pause between rings).
-W—hen abnormal voltage is detected (hardware error), the buzzer.—
rings five times (for 0.5 sec. each, with 0.5 sec. pause between rings).
When the paper end sensor detects paper out, the state of the interface changes as follows:
ERROR signal ~ LOW
BUSY signal ~ HIGH
PE signal+ HIGH
The printer enters an error state when any of the following occurs:
a. Home position is not detected after the printer mechanism has been initialized (home
seek).
position
b. The +24V voltage (which is used to drive the printhead and motors) rises to +27V or more.
When the printer enters an error state, the printer stops the printing, and the state of the interface
changes as follows:
ERROR signal ~ LOW
BUSY signal ~ HIGH
1.4.6 Printer Initialization and Default Values
The LX-800 initialized when any of the following occurs.
q
q
When
a.
b.
c.
d.
e.
f.
9“
i.
The power switch is turned on.
Intetiace signal INIT goes low.
the printer is initialized, the following operations are performed:
Seek to carriage home position.
Set to ON-LINE mode.
Clear the all buffers.
Set the line spacing to 1/6 inches.
Set the page length to 11 or 12 inches, according to the DIP switch.
Clear all vertical tab positions.
Set the horizontal tab position to every 8 columns.
Set the print mode according to the DIP switches.
1-17

REV.-B
1.5 MAIN COMPONENTS
The LX-800 consists of the following components:
q Printer Mechanism Model-3A10 (include the Tractor Unit)
q ROC Filter Unit
q ROCX Board Unit
q LCPNL Board Unit
q Housing
1.5.1 Printer Mechanism Model-3A10
The Model-3A10 printer mechanism was developed expressly for use with LX-800 printer: the
components include a carriage motor, carriage mechanism, paper feed motor, paper feed mechanism,
ribbon feed mechanism, printhead, sensors, and the tractor unit. For the tractor unit, there are two tabs
on both side frames to allow the printer cover to float slightly when tractor feeding is performed.
Fig. 1-11. Model-3A10 Printer Mechanism
1-18

REV.-A
1.5.2 ROC Filter Unit
The ROC filter unit contains a power cord ( 120 V version) or AC inlet (220/240 V version), power switch,
fuse, filter circuit, and power transformer.
..—
Fig. 1-12. ROC Filter Unit (120V version)
Fig. 1-13. ROC Filter Unit (220 V/240V versions)
1-19

REV.-A
1.5.3 ROCX Board Unit
The ROCX board contains the main control circuit, driver circuit, and voltage regulator circuit. The main
ICS on the ROCX boards are the pPD78 10HG CPU and the E05A03 gate array which controls everything.
----=--
/
. Y
Fig. 1-14. ROCX Board Unit
1.5.4 LCPNL Board Unit
The LCPNL board unit is a control panel of LX-800 which contains the indicator LEDs, switches and
buzzer.
Fig. 1-15. LCPNL Board Unit
1-20

REV.-A
1.5.5 Housing
The housing is comprised of the upper and lower cases, and paper feed knob, which accommodate
the printer mechanism, ROCX board unit, LCPNL board unit, and ROC filter unit.
Fig. 1-16. Housing
1-21

REV.-A
2.1
2.2
2.3
2.4
CHAPTER 2
OPERATING PRINCIPLES
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
CABLE CONNECTIONS....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-3
POWER SUPPLY CIRCUIT 2-3
2.3.1 ROC Filter Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2.3.1.1 Fuse and Filter Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.1.2 Power Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-4
2.3.2 Regulator Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-5
2.3.2.1 Operation Principles of Chopper
Type Switching Regulator...............................................2.6
2.3.2.2 +24V Supply Circuit .......................................................2-7
2.3.2.3 +5V Supply Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-8
CONTROL CIRCUIT......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
2.4.1 Functions of the CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-11
2.4.2 E05A03 Gate Array Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-14
2.4.3 Data Flow .........................................................................................2-18
2.4.3.1 Initialization ........................................................................2-19
2.4.3.2 Print Data Processing .....................................................2-20
2.4.4 Reset Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-22
2.4.5 Carriage Motor .............................................................................2-23
2.4.5.1 Home Position Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
2.4.5.2 Carriage Motor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-24
2.4.5.3 Home Position Seek. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-26
2.4.5.4 Carriage Motor Drive Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27
2.4.6 Paper Feed Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2-27
2.4.6.1
2.4.6.3
2.4.6.3
2.4.6.4
Paper End Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29
Paper Feed Motor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29
Auto Loading Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-30
Paper Feed Motor Drive Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31
2.4.7 Printhead ........................................................................................2-32
2.4.7.1 Printhead Control .............................................................2-32
2.4.7.2 Printhead Drive Pulse Width Control Circuit . . . . . . . . . 2-33
2.4.7.3 Printhead Drive Circuit ..................................................2-34
Z.i

REV.-A
2.5
Fig.
Fig.
Fig.
Fig.
2.4.8 Print Timing Control ..................................................................2-34
2.4.8.1 Print Timing Control for the
Carriage and Printhead ....................................................2-34
2.4.8.2 Bidirectional Logic Seeking ...........................................2-35
PRINTER MECHANISM OPERATION ..............................................2-37
2.5.1 Sensor Mechanism .....................................................................2-37
2.5.2 Carriage Mechanism ..................................................................2-38
2.5.3 Paper Feed Operation ................................................................2 4 0
2.5.3.1 Friction Feed Operation ..................................................2 4 0
2.5.3.2 Sprocket Feed Operation ...............................................2-40
2.5.4 Ribbon Feed Mechanism ...........................................................2 4 2
LIST OF FIGURES
2-1. Cable Connections ......................................................................2-2
2-2. Power Supply Circuit Block Diagram .................................. 2-3
2-3. Filter Circuit ..................................................................................2 4
24. Power Transformer .....................................................................2 4
Fig. 2-5. +24V/+5V DC Regulator and
+ 12V Half-Wave Rectifier Circuits ...................................... 2-5
Fig. 2-6. Chopper Switching Regulator Circuit .................................. 2-6
Fig. 2-7 Voltage Waveforms .....................................................................2-6
Fig. 2-8 +24V Supply Circuit ..................................................................2-7
Fig. 2-9 IC494 Block Diagram and Switching Waveform . . . . . . . . . . . . . 2-7
Fig. 2-10
Fig. 2-11.
Fig. 2-12.
Fig. 2-13.
Fig. 2-14.
Fig. 2-15.
Fig. 2-16.
Fig. 2-17.
Fig. 2-18.
Fig. 2-19.
Fig. 2-20.
Fig. 2-21.
Fig. 2-22.
Fig. 2-23.
+5V Supply Circuit .....................................................................2-8
Control Cirucit Block Diagram ...............................................2-10
E05A03 Block Diagram ............................................................2-14
LX-800 Memory Map .................................................................2-18
Initialization Flow........................................................................2-19
Print Data Flow ...........................................................................2-20
Line Buffer.....................................................................................2-21
Reset Circuit .................................................................................2-22
Home Position Sensor Circuit.................................................2-23
Basic Phase Switching Patterns ...........................................2-24
Basic Operation Sequence .......................................................2-24
Home Position Seek Operation Flow ................................... 2-26
Carriage Motor Drive Circuit ..................................................2-27
Paper End Sensor Circuit .........................................................2-28
2-ii

REV.-A
Fig. 2-24. Paper End Detection Area .......................................................2-28
Fig. 2-25. Phase Switching Basic Pattern .............................................2-29
Fig. 2-26. Basic Operation Sequence ................... mm.m.o.m..mm........ ..a...- 2-29
Fig. 2-27. Printing Start Position ..............................................................2-30
Fig. 2-28. Paper Feed Motor Drive Circuit .............................................2-31
Fig. 2-29. Printhead Drive Pulse Pattern ................................................2-32
Fig. 2-30. Printhead Drive Pulse Width Range .................................... 2-33
Fig. 2-31. +24V DC Monitor Circuit..................................................... 2-33
Fig. 2-32. Printhead Drive Circuit .............................................................2-34
Fig. 2-33. Solenoid Current and Drive
Voltage Waveforms ....................................................................2-34
Fig. 2-34. The Relationship Between the Carriage
and Control Signals ......................................................................2-35
Fig. 2-35. Logic Seeking ...............................................................................2-36
Fig. 2-36. Printer Mechanism External View (Model-3A10) . . . . . . . . . . . . 2-37
Fig. 2-37. Carriage Mechanism ..................................................................2-38
Fig. 2-38. Printhead Printing Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-39
Fig. 2-39. Friction Feed Operation ............................................................2-40
Fig. 2-40. Sprocket Feed Operation ..........................................................2-41
Fig. 2-41. Ribbon Feed Mechanism ..........................................................2-42
LIST OF TABLES
.
Table 2-1. Voltage Types and Applications ...........................................2-3
Table 2-2. Power Transformer Output Voltages.................................. 2-11
Table 2-3. CPU Port Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Table 24. E05A03 Functions .....................................................................2-16
Table 2-5. E05A03 Port Assignments .....................................................2-17
Table 2-6. Ribbon Feed Gear Train ...........................................................2 4 2
2-iii

REV.-A
2.1 GENERAL
This chapter describes the component connections, specifications and operation of the power supply
circuit section, the software for the control circuit section, and the operation of the hardware and the
printer mechanism.
Please note that the following units are assumed when omitted in this chapter.
Resistor: Units are Ohms.
Capacitor: Units are Farads.
The components listed below are referred to as follows:
ROCX board: Main board
LCPNL board: Control panel
Model-3Al O: Printer mechanism
— .—
2-1

REV.-B
2.2 CABLE CONNECTIONS
Figure 2-1 shows the interconnection of the primary components, with the main board at the center.
ET=
I MODEL-3A1O PRINTER MECHANISM I
ON
1 J
CR PRINT PAPER HOME
‘f;OuOTjR
HEAD END Posh
I I
CN5
I
CN4
12pin 12pin c @
“~ z
N v
L
1
ROCX BOARD c h‘z z
g .g
Vcn ( M A I N B O A R D ) m ~A
ROCK FILTER UNIT
.= N
n z /
AC120V
g u
c co
b ‘~ z AC220V* u
36pin AC240V
CN1 (POWER TRANSFORMER
AND FILTER)
r8-BIT I
1 #8100 SERIES I
PARALLEL I l/F BOARD I
l/F A—- - - -—1
/1 R
Ail 20V
AC220V
AC240V
Fig. 2-1. Cable Connections
The ROCX board connectors are as follows:
CN 1 :
CN2:
CN3:
CN4:
CN5:
CN6:
CN7:
CN8:
8-bit parallel interface connector. Used for data communication with the host computer.
Connector for the #8 100 series optional interface
Receives data from the LCPNL board switches, and outputs the signals to the LEDs and the
buzzer.
Outputs data to the printhead.
Outputs the control signals and drive voltages to the paper feed and carriage motors.
Receives the paper end signal from the printer mechanism.
Receives the home position signal from the printer mechanism.
Receives AC voltages from the ROC filter unit.
The pin numbers and functions for each connector are listed in Tables A-8 through A-15 of the
APPENDIX.
2-2

REV.-A
2.3 POWER SUPPLY CIRCUIT
This section describes the operation of the ROC filter unit and regulator circuit on the ROCX board.
Figure 2-2 shows the block diagram of the power supply circuit. Table 2-1 shows output voltages and
their applications.
---—- - -— - ------q _ - _ . - - - - - - - - - - — - - - - - - - - - 7I Power
i r-l
JI
SwNch
~- F i l t e r
I
IN i
Circuit
1
I
I
I
I
I
—
2.3.1
Power
Trans-
1 I I
I I F2
. I
I Full-Wave O + 24VDC
I I Rectifier ~ Switching I
:AC1 ~ and Regulator I
II Smoothing Circuit I
I
O GP
circuit
T
I
I
II
I
1AC2 I
— Switching ~ + 5VOC
II
Regulator I
1; Circuit ‘
II
~ GND
L -—-----——- — - - JI I : ~ — 1
ROC Filter Unit
1 I
4 — - t Half-Wave
I
I o + 12V
I Rectifier I
4 Circuit I 0 GND
I
I I
I O 12VAC
I I
I O 12VAC
k - — - . - - - - - - - - - - - - - - - - - - - A
ROCX Board
Fig. 2-2. Power Supply Circuit Block Diagram
Table 2-1. Voltage Types and Applications
Power Voltage Application
+ 24 VDC-GP Printhead common voltage
Paper feed motor drive voltage
Carriage motor drive voltage
Optional interface board
+5 VDC-GND Logic circuit
Paper feed motor hold voltage
Carriage motor hold voltage
Control panel power
Optional interface board
+ 12VDC-GND Optional interface board
12V AC Optional interface board
ROC Filter Unit
The ROC filter unit consists of an AC power cord (or AC power inlet), power switch, fuse, filter circuit,
and power transformer. The AC power cord, AC power inlet, fuse, and power transformer differ
depending on the power supply voltage. Three kinds of ROC filter units, for 120 V, 220 V, and 240 V,
are available.
2-3

REV.-A
2.3.1.1 Fuse and Filter Circuit
The AC input from the power line first flows across the power switch and fuse F1. After being filtered
by C 1 and C2, it is supplied to the primary side of the power transformer via the L1/C3 noise prevention
circuit. Power line noise (external noise) and internal noise from the printer are eliminated by this circuit.
The value of fuse F1 changes as follows, according to the power supply voltage:
120 V version: 125 V or 250 V, 1.25 A
220 V version: 250 V, 0.63A
240 V version: 250 V, 0.63A
Power
F1 Switch
r’;;
To @pin of
. 0
Power Transformer
c l
L1
29~H
2200PF – C3
AC IN x2 –
0.1 IF
C2 ==
To @pin of
0 Power Transformer
////
Fig. 2-3. Filter Circuit
2.3.1.2 Power Transformer
Three types of power transformers, for 240 V, 220 V, and 120 V, are available. The AC voltage from
the filter circuit is transformed to the voltages listed in Table 2-2 so that they can be output to the
regulator circuit (on the ROCX board) at the next stage. The power transformer includes thermal fuses
TF1 and TF2.
TF1
T
a)~50/60Hz
@
primary side
CN 1
Gii=El:
Secondary Side
To the
ROCX Board
Fig. 2-4. Power Transformer
..
2-4

REV.-A
Table 2-2. Power Transformer Output Voltages
Rated Voltage
Type Pin No. No-load AC Voltage [V]
AC [V] DC [V]
220V 0-0 29.3 27.1 32.3
240V
@-@ 9.0 8.33 +9.0/– 9.9
a-o 29.3 27.7 33.3
120V
n-m 8.96 8.41 +9.27/– 10.0
NOTE: Column “DC @/]” for the rated voltages indicates the output of the transformer when the ROCX
board is connected. The plus and minus values between pins 10 and 9 are different due to the
voltage drop across thermal fuse TF2.
2.3.2 Regulator Circuit
AC-tind AC2 output from the ROC filter unit are input to connector CN8 of the ROCX board. The
regulator circuit can be divided mainly into two portions, the +24 V/+5 V and + 12 V lines. AC 1 is
full-wave rectified by diode bridge DB 1 and converted to +24 V and +5 V via the chopper type
switching regulator. AC2 is half-wave rectified by D4-C 10, converted to + 12 V, and input to the optional
interface board.
T20v:
r, r , r
2M-3.ISA-MI Otal-3.1=1 m az, _
KV 3.15A ~m 0747
.24V
F2
cl-
q MT
q WI C;t a 13A) *UK
=‘~’i “=*V
, pPc494c
‘ I **II In, I
1
04
3 2M01n3
R6S
O.in
Sc2
1
WI 2!3
Clo
1000,
4
Au
Fig. 2-5. +24/+5 VDC Regulator and +12 V Half-Wave Rectifier Circuits
2-5

REV.-A
2.3.2.1 Operation Principles of Chopper Type Switching Regulator
The operating principle of the switching regulator is illustrated in Figures 2-6 and 2-7.
“ :fl,~
St
Fig. 2-6 Chopper Switching Regulator Circuit V/I
1 C) Max = J+
L
Vi - VO
= .tc
1P
IPtD + IOt 1
c = v,
10
to = ~ - L
Fig. 2-7 Voltage Waveforms
When switching transistor St is on, current Is is supplied to inductor L in proportion to time;
,s = (vi –L Vo) t
When energy has accumulated in the inductor L, current 10 is supplied to the load. When St is off, the
energy accumulated in L causes
I D =
Ip – * t
current ID to flow via diode D and to supply load current 10;
The longer the on-time of St, the more the output voltage increases, and the shorter the on-time of St,
the more the output voltage decreases. Theoretically, electric power efficiency is assumed to be 100%;
Output voltage Vo = + Vi
2-6

REV.-A
2.3.2.2 +24 V Supply Circuit
The +24 V supply circuit is a chopper type switching regulator circuit. Figure 2-8 shows the block
diagram of the +24 V supply circuit based on Figure 2-6.
Q25
L2
125V R67
o.47/3w
LP401 -02SD
3.1 5A C3747
Q +24VDC
DB1 F2 R50
D3SB1 o
2 4/0 5
w
a
R49
AC1 Q
C22 330
z+ 6800 /-f z ~ ~ C26
50V R47 2200jL35V
(3A) 3.3K
AC1 O
494
ZBF503
R46
-01 TA
330
OGP
— Fig. 2-8. +24 V Supply Circuit
AC 1 input from the ROC filter unit is full-wave rectified by DB 1 and is smoothed by C22. The voltage
across C22 becomes 32.3 VDC. Transistors Q23, Q24, and Q25, which are used as Darlington
amplifiers, D7, L2 and C26 in Figure 2-8 are equivalent to switching transistor St, flywheel diode D,
choke coil L, and smoothing capacitor C in Figure 2-6. Switching is controlled by the 494 (IC3A), and
pin 9 of the 494 is the emitter of the internal switching transistor. Therefore, switching is performed
as follows:
494 internal transistor: ON ~ Q23: ON ~ Q24: ON ~ Q25: ON
494 internal transistor: OFF ~ Q23: OFF ~ Q24: OFF ~ Q25: OFF
Figure 2-9 shows a block diagram of IC 494.
a
+323V
~ . - - - ,
! +24VDC
DC T
1/6w
GND v
IC 3A ?!”5
Oscdat.r W,v.-fonll
, , 1 1 i, 1
Q IC 3A Ptn9
1,, ”s!s,., W... -from
f
I
: 1,11
c Q25 Ern,tw
W.v.-fom
( f [ ( [ ( (
Fig. 2-9. IC494 Block Diagram and Switching Wava-form
2-7

REV.-A
When the printer power is turned on, ZD1 on the +20 VDC line turns on, Q22 turns on, and Vcc is
applied to IC 494. Then the oscillator (OSC) starts generating an approximately 20 kHz sawtooth
waveform, which is regulated by R40 and C20, and the reference voltage generator outputs the +5
VDC 10% reference voltage. Internal switching transistor Tr is switched on and off using the output
from error amplifiers 1 and 2. EA1 and EA2 limit voltage and current, respectively. EA1 compares the
voltage obtained by dividing the +24 V applied to pin 1 by R22 and R21 (approx. 4.9 V) with the + 5
V reference voltage applied to pin 2. EA2 compares the voltage monitored by R66 with the voltage
obtained by dividing the +24 V applied to pin 16 by R21 (approx. 0.31 V). Therefore, the current is
limited to approximately 3.1 [amps].
2.3.2.3 +5 V Supply Circuit
The +5 V supply circuit is also a chopper type switching regulator, which is the same as the +24 V
supply circuit.
L1
+24V
GP
Q21 C9 ~P201 –2R5SD
o
C3746 470P
Q20
Al O 15(
RI 4 D1
, 2 0 2 K S R I ERB81
R12 ~1 78L05A – 0 0 4
33 R1 1 1
Vvv I
2
0 – =
330 G
13 B7
1 Ov
()
R13 0.1- -
ZBF503
2 C8
-=01 TA
o A
T Q GND
77)7-
Fig. 2-10. +5 V Supply Circuit
When +24 V is applied to this circuit, current flows via R12 and R1 1, and operation of SR1 is started.
SR1 includes a +5 V reference voltage generator and compares the voltage at terminal O (pin 2) with
the reference voltage. When this voltage is lower than the reference voltage, SR 1 turns terminal I (pin
1 ) on. If the voltage is higher than the reference voltage, SR 1 turns the terminal off. This controls the
switching transistors Q20 and Q21, and the output voltage is kept constant. Actual output voltage is
5.024 V (calculated value) because the GND terminal (pin 3) of SR 1 is raised to 0.024 V using the divider
composed of R 14 and R 13.
2-8

REV.-A
2.4 CONTROL CIRCUIT
This section describes the software operation, specifications, and circuit operation of the control circuit
(ROCX board). This section consists of the following descriptions:
1. Function of the CPU which controls the overall operation and its peripheral circuits (Section 2.4.1)
2. Gate array function (Section 2.4.2)
3. Outline of the overall firmware operation (Section 2.4.3)
4. Software control and circuit operation of the analog circuits (Sections 2.4.4 through 2.4.8)
The control circuit is very simple, and consists mainly of four chips: the CPU, gate array, ROM, and RAM.
(Refer to Figure 2-1 1.) The main operation of the control circuit is to control the CPU and the gate array.
Other components are described in each section that describes the functions of the CPU and gate array.
Figure 2-11 shows a block diagram of the control circuit.
..—
2-9

REV.-A
PESENSOR
PAPER FEEC
MOTOR
CARRIAGE
MOTOR
HOME
PRINT
HEAD
/
I
I
I A G.A. E 0 5 A 0 3 B A
Ill
I
I l l
)mho ho
. -–r m-m G m-m
mmoo u
4

‘f”)
‘u’ Fig. 2-11. Control Circuit
HOST COMPUTER (OPTIONAL
Fig. 2-11. Control Circuit Block
2-1o
IIF BOARD)
Diagram
1
—
Block Diagram

REV.-B
2.4.1 Functions of the CPU
The core of the control circuit is the 78 10H CPU (IC2B). Table 2-3 shows the function of each pin and
the related circuits.
Table 2-3. CPU Port Assignments
Pin
Number
Port
Assignment
1/0 Signal Line
Name
Description
1/0 port. Switches the carriage motor drive voltage and the
holding voltage. When this signal is HIGH (LOW), the drive
voltage (holding voltage) is applied to the carriage motor.
Not used.
1 PAO o CRCOM
2
3
PA1 —
PA2 o PFCOM 1/0 port. Switches the paper feed motor drive voltage and the
holding voltage. When this signal is HIGH (LOW), the drive
voltage (holding voltage) is applied to the paper feed motor.
LF SW 1/0 port. Reads the state of the LINE FEED switch on the
control panel.
1/0 port. Reads the state of the FORM FEED switch on the
control panel.
4 PA3 I
I FF SWPA4‘ - 5
6 PA5 I PE SW 1/0 port. Reads the state of the paper end sensor. When no
paper is loaded, this signal goes LOW.
Not used.7 PA6 —
P/s
SW1 - 8
1
Swl - 1
TXD
1/0 port. Reads the P/~ signal from the optional interface.
1/0 port. Reads the state of DIP SW1.
8
9
t
16
17
18
19
PA7
PBO
!
PB7
Pco
I
I
o
I
TXD output port. Outputs the data from the serial 1/0 channel
in the CPU to the TXD (transmit data to the host computer)
terminal of the optional interface.
Pcl RXD RXD input port. Used as a receive control signal when the
optional serial interface board (for serial/parallel data conver-
sion) is connected. (Data reception detection)
ONLINE LPPC2 o 1/0 port. Controls the ON LINE LED on the control panel. When
this signal is LOW, the LED lights.
ONLINE SW INT2 input port. Reads the state of the ON LINE switch on the
control panel. Connected to the interrupt controller in the CPU,
which executes the ON LINE/OFF LINE switch interrupt routine
when this signal is LOW.
20 PC3 I
Em21 PC4 o 1/0 port. Outputs an error signal to the interface board when
the printer is in an error state. When this signal is LOW, the
printer is in an error state.
ACKNLG22
23
24
PC5 o
0
0
1/0 port. Outputs the acknowledge signal to the interface. This
signal is LOW active.
COO output port. Outputs the drive pulse width signal, which is
determined by the timer/event counter in the CPU, to the FIRE
terminal of gate array E05A03. This signal is LOW active.
PC6 FIRE
PC7 BUZZER 1/0 port. Outputs the buzzer signal to the control panel. When
this signal is LOW, the buzzer rings.
2-11

REV.-A
Table 2-3. CPU Port Assignment (cent’d)
Pin Port ,,0 Signal Line
Number Assignment Name
Description
25 NMI I — Non-maskable interrupt input. The interrupt routine is executed
at the trailing edge of this signal. This pin is invalid because it
is tied to ground.
26 INT 1 I — Interrupt input. The interrupt routine is executed at the leading
edge of this signal. This pin is invalid because it is tied to
ground.
27 MODE 1 I — External memory space setting port. MODES 1 and O (pin 29)
are both pulled up to HIGH so that an external memory of 64K
bytes (addresses O through FFFFH) can be used.
28 RESET I RESET Reset terminal. When this signal is LOW, the printer is reset,
and ports A through C and D are set to be high impedance
input ports, and port F is set to be an address output (start
address OH).
29 MODE O I — Refer to pin 27, MODE 1.
30 x 2 CPU external clock input. This printer is driven with a 14.74
I —
31 x l
MHz clock. The operation codes are fetched at approximately
1.3 MHz, and memory read/write operations are performed at
approximately 1.6 MHz.
32 Vss - — Ground terminal.
33 AVSS — Ground terminal for the A/D converter in the CPU.
34 ANO SW2-1 Analog input port of the 8-bit A/D converter in the CPU. Reads
1 i I 1 the states of DIP SW2-1 through SW2-3.
36 AN2 SW2-3
37 AN3 I SW2-4 Analog input port of the 8-bit A/D converter in the CPU. Reads
the state of DIP SW2-4. This signal line is connected to the
AUTO FEED XT signal line of the interface. When DIP SW2-4
is ON, the automatic paper feed function is valid. When the
DIP switch is OFF, this function is controlled by a signal from
the host computer (not fixed).
38 AN4 I — Analog input port for the 8-bit A/D converter in the CPU.
Reads the SLCT IN signal from the interface. When the SLCT-
~ signal is HIGH, DC l/DC3 control from the host computer is
valid. When it is LOW, DC l/DC3 control is ignored, and the
printer is always selected as a device. (The signal can be tied
LOW using jumper J 1.)
39 AN5 I + 2 4 Analog input port for the 8-bit A/D converter in the CPU.
Monitors the +24 V voltage and controls the printhead drive
pulse width.
40 AN6 - — Not used.
41 AN7 - — Not used.
42 VAREF I — Reference voltage input for the 8-bit A/D converter in the CPU.
4 3 A VC C I — Power supply input for the 8-bit A/D converter in the CPU.
4 4 m o m Memory read timing strobe signal. Connected to the RD strobe
terminal of the gate array and the output enable terminal of
the ROM and RAM.
2-12

REV.-B
Pin
Number
45
46
47
1
54
55
1
62
63
.—
64
Port
~ssignment
WR
ALE
PFO
1
PF7
PDO
!
PD7
V D D
Vcc
Table 2-3. CPU Port Assignment (cent’d)
1/0
o
0
0
1/0
I
I
Signal Line
Name
WR
ALE
A 8
[
A 15
DBO (AO)
!
DB7 (A7)
—
Description
Memory write timing strobe signal. Connected to the WR
strobe terminal of the gate array and the write enable terminal
of the RAM.
Address latch enable signal. Controls address latching per-
formed inside the gate array (enables latching when the signal
is HIGH).
8-bit 1/0 ports with output latch. Used as the upper address
bus according to the MODE 0/1 terminal selection. For 64K
external memory assignment), Al 3 through Al 5 are input to
the address decoder in the gate array.
Multiplexed addressldata bus. Used as the lower address and
data bus.
Power supply for the internal RAM (+5 VDC)..—
Power supply for the CPU (+5 VDC). When this voltage is not
stable, such as at either a leading or trailing edge (when the
printer power is turned on or off), the reset circuit prevents the
CPU from running.
NOTES: 1. All barred signal are LOW active.
2. “1/0” denotes either input or output when viewing the signal from the CPU.
2-13

REV.-A
2.4.2 E05A03 Gate Array Functions
This section describes the E05A03 functions. Figure 2-12 shows the E05A03 block diagram.
(3
STROBE
I NO-7
DBO-7
ALE
DB6
DB7
~T
RESET
(RESI)
AB15
AM4
AB13
TIMING
REGISTER
LATCH
(Input
Data)
I I I
—
1
A
1
-
I I I I I ~’ I 11 l-lI I III L
PRINTHEAD
DRIVER
-
IATCH
(ControIl
( w
CARRIAGE
MOTOR DRIVER
BUSY
RESO
Fig. 2-12. E05A03 Block Diagram
2-14

REV.-A
Functions of the E05A03 gate array (IC3B) are as follows:
1. Address latch
The gate array latches data on address data lines DBO - DB7 at the leading edge of the ALE signal,
and outputs it to ABO - AB7 (when ALE is high, the data is passed through without latching.)
2. Address mapping
The gate array inputs an address on AB 13-
——
AB 15, and selects CS 1 or CS2 or enables the R/W mode
of this gate array using internal decoder 2.
3. Handshaking
q The gate array latches data on INO - IN7 at the leading edge of the STROBE signal, and automatically
outputs the BUSY signal. The BUSY signal (DB7) is latched by the timing register to inform the CPU
that data has been transmitted to the CPU.
q The timing for the BUSY signal, which is set at either the trailing or leading edge of the STROBE
signal, is selected by the control program (firmware).
q The BUSY signal output from the timing register is wire-ORed with the BUSY signal controlled by
the firmware.—— .—
4. Printhead solenoid drive pulse
. When the FIRE signal from the CPU is brought Low, the data that was previously latched is output
on HD 1 - HD9 to drive the corresponding solenoids in the printhead.
q When FIRE is high, HDI - HD9 are all low.
5. Shift register
q This gate array includes a shift register (8bits X 3), and the MSB (Most Significant Bit) can be read
by accessing the specified address (XX03H) once. The data is shifted one bit to the left at the leading
edge of the ~ signal.
6. Initialization
——
When the INIT or RESI signal is low, the gate array sets RESO low and initializes the following.
q Printhead latch (HD 1 - HD9 are all set low even if FIRE is low.)
q PF motor latch (PFA - PFD) are all set low.)
——
q CR motor latch (CRA - CRD) are all set high.)
. Timing generator (enters the state indicating that no data has been received.)
q Control latch (BUSY is set high (software-BUSY), PE is set low, and PELP, NLQLP, and CNDLP are set
high.)
7. Address decoder 2
Address decoder 2 selects one of the twelve modes listed in Table 2-13 according to the combination
of lower address bits OOH - 07H, ~, and ~.
2-15

REV.-A
Table 2-4 shows the E05A03 functions and Table 2-5 shows the E05A03 pin functions.
Table 2-4. E05A03 Functions
Lower Address R / W Pin Name Function
R INO - IN7
Reads the data which was latched using STROBE, and resets
OOH
the STROBE-BUSY output.
w
Writes data to the upper eight bits of the 24-bit shift register
—
(DB7 - DBO ~ Bits 23 - 16).
R
STRB Bit 7: 1 (Indicates the trailing edge of the STROBE signal.)
HOME Bit 6: 1 (The HOME input is HIGH.)
OIH
w
Writes data to the middle eight bits of the 24-bit shift register—
(DB7 - DBO ~ Bits 15 - 8).
R INO - IN7 Directly reads INO - IN7. Does not affect the BUSY signal.
02H
w
Writes data to the lower eight bits of the 24-bit shift register—
(DB7 - DBO ~ Bits 7 - o).
R
Reads the MSB of the 24-bit shift register and shifts the data—
one bit to the left (MSB ~ DB7).
Bit 7: 1 (The BUSY signal is output at the leading edge of
STROBE.)
O (The BUSY signal is output at the trailing edge of
BUSY STROBE.)
Bit 6: 1 (Resets software-BUSY.)
03H O (Sets software-BUSY.)
w
NLQLP
Bit 4: 1 (NLQLP is LOW.) q See NOTES 2.
0 (NLQLP is HIGH.)
CNDLP
Bit 3: 1 (CNDL is LOW.) ‘See NOTES 2.
0 (CNDL is HIGH.)
PE Bit 2: 1 (PE is HIGH and PELP LOW.)
PELP O (PE is LOW and PELP HIGH.)
Latches (and inverts) the data for pins 1 - 8 of the printhead.
04H w HD1 - HD8 (DB7 - DBO ~ HD1 - HD8 Data is output when FIRE goes
LOW.)
05H w HD9
Latches (and inverts) the data for pin 9 of the printhead. (DB7
~ HD9 Data is output when FIRE goes LOW.)
06H w PFA - PFD
Latches the phase data for the PF motor.
(DB7 - DB4 ~ PFA - PFD)
07H
——
w CRA - CRD
Latches the phase data for the CR motor.
(DB3 - DBO ~ CRA - CRD)
NOTES: 1. The above functions are mapped to every eight bytes from COOOH to DFFFH.
2. These are not used in this printer.
2-16

Table 2-5. E05A03 Port Assignments
Pin No. Signal Direction Description
1 Vcc In Power (+ 5V DC)
2 NLQ LP o u t NLQ lamp (~/off) “See NOTES 1
3 PE LP out Paper end lamp (~/off)
4 CR D out Carriage (CR) motor phase D drive pulse
5 CR C out CR motor phase C drive pulse
6 CR B out CR motor phase B drive pulse
7 CR A out CR motor phase A drive pulse
8 DB 7 In/Out Data bus 7 - 0
1 !
15 DB8
16 AB 15 In Address bus 15 - 13
1 1
18 AB 13 In
19 ALE In Address latch enable
. — 2 0 WR In Write stroba-
21 m In Read strobe
22 FIRE In Printhead solenoids trigger (_/rest)
23 HOME In Home position signal (Home/Not home)
24 RESI In Reset signal input
25 RESO out Reset signal output
26 PF A out Paper feed (PF) motor phase A drive pulse
27 PF B out PF motor phase B drive pulse
28 PF C out PF motor phase C drive pulse
29 PF D out PF motor phase D drive pulse
30 Cs 1 out Chip select 1 (lower address)
31 Cs 2 out Chip select 2 (upper address) “See NOTES 1.
32,33 GND — GND
34 CND LP out CONDENSED lamp (on/off) q See NOTES 1.
35 PE out Paper end (Valid/Invalid)
36 BUSY out Busy
37 AB O out Address bus O - 7
1 1
44 AB 7
45 INIT In Initialize
4 6 STROBE In Strobe
4 7 IN 7 In Data bus 1 - 8
1 i
5 4 IN O
5 5 HD 9 out Printhead solenoid drive pulse #9 - #1
{ !
6 3 HD 1
6 4 Vcc In Power (+ 5V DC)
NOTES: 1. These are not used in this printer.
2. Signal direction is viewed from the E05A03 side.
2-17

REV.-A
2.4.3 D a t a F l o w
This section describes the firmware start-up operation when the printer is initialized, data flow
(especially printing data flow), and command processing.
LX-800.
FFFFt
FFOOt
EOOOI
Coool
AOOOI
80001
00001
CPU Internal RAM Area
(Down Load Area)
Not Used
Gate Array Function
Address Area
(Memory Mapped 1/01
Not Used
Buffer and Work Area
(RAM IC4CI
8k bytes
Program Area
(ROM IC3C)
32k byles
Figure 2-13 shows a memory map of the
Stack Area
Lim Buffer
I

hag. Buff.,
(2K bytes)
l hut Oata Buffer I
l i3k bvtes) I
Fig. 2-13. LX-800 Memory Map
The CPU can access an external memory of 64K bytes, and executes the program (32K bytes) in the
external ROM (IC3C). The external RAM (IC4C) area (8K bytes) and the CPU internal RAM (256 bytes)
are used as a buffer and working area. The CPU accesses the gate array using the instruction codes
(See Table 2-4). COOOH through DFFFH are defined as memory mapped 1/0.
2-18

REV.-A
2.4.3.1 Initialization
When the reset signal is input, the printer is initialized as follows:
CPU 4
GATE ARRAY
————— .— ———————— — — . — — . —— 1
i I
; Clears the ports using hardware resetting. I
Clears all port outputs. Executes the program from t q Sets the print head data to High-Z(the high 1
address OH. I
1 impedance state).
I q Sets the BUSY signal HIGH. I
1
~------------------------’i ————— ——————————————— 1
Sets up the 1/0 ports. Initializes the CR and PF ~ Receives the phase data for the motors from the I
motors. I CPU, and holds the CR and LF motors.
1 — — —— — ——— — — — — —- — -—-—--—--—- 1
$
Clears the memory. Sends the ACK signal to the
host computer via the interface.
I
-“’’’’’’’’’’’’’;’’’”:lPerforms carriage home position seek.
tb
— — — — — — — — — — — — — ————— —— ————
1
Initializes the gate array. I
; Initialized (the instruction codes are set). i
(Outputs the instructions to the gate array.)
I — .———.—————— - — — — ——— — —— 1
~--------------------- --
I
i I
Reads the DIP switch settings on the optional in-
I Reads the DIP switch settings on the optional in-
! terface board upon receiving the instruction code.
terface board if the board is installed. ; (XX02H is read.)
1 I ————— —————————. -— ——— ———— J
Checks whether the paper is set or not. Sends the ~ Controls the paper end signal of the interface and I
result to the gate array. I the paper end l a m p o n t h e control panel.
I — — — — — - — — — — — — — — - — — — — — — - —— J
Is this self-test printing or hex-
adecimal dump mode? (Moni- Y
tors the switch signals from
I
Select either the self-test
printing or the hexadecimal
dump mode.
Enters the interface waiting state (main routine for ~ Entars tha interface data waiting state. I
data processing). I q Sets the BUSY signal LOW.
I — — — — — — —— ———— .————————— J
Fig. 2-14. Initialization
2-19
Flow

REV.-A
2.4.3.2 Print Data Processing
After the initialization, the CPU enters the data waiting state. When data is input from the interface,
the CPU starts reading the data. Besides this process (main routine), the actual printing process is
performed by an interrupt routine. The print data is processed by repeating the main and interrupt
routines.
Array

CPU
Data
@- —D
— ACK
Input
Data
5
–m ~
STRB -----
$ D @ -
Buffer
~
2
t
* BUSY ---- A *
@ J
Command
Analyze
(Add the
9
4
Attribute)
* : M a i n routi”e
- : Interrupt ro”tine
(!)7
fiACG 6
; Down I
~ Load ~
- - r - - -
eCG Copy Araa
+
FIRE
P
Imaga Buffer
I I
oPrinting
Fig. 2-15. Print Data Flow
The data flow in the Draft printing mode is as follows. Step numbers used in the explanation below
correspond to the data flow numbers used in Figure 2-15.
2-20

REV.-A
@ The CPU detects the STRB signal from the gate array (Reads MMIO and XXOI H). When the gate
array detects the trailing edge of the STRB signal, it automatically sets the BUSY signal HIGH and
latches the transferred data.
@ The CPU fetches the data latched by the gate array (reads MMIO and XXOOH), and stores the data
in the input buffer. The CPU analyzes each byte of data to determine whether it is a control code
or print data, then returns the ACK signal to the interface.
@ Steps@ and@ are repeated until the input data buffer becomes full. When the buffer becomes full,
the BUSY signal is set HIGH.
@ Either during steps@ and@ or after the input data buffer becomes fuil, the CPU analyzes each byte
of data. If the data is not a printing command (CR), the CPU sets the printing mode and parameters
and transfers the data to the line buffer. The line buffer is shown in Figure 2-16.
—
. - ----
Character Attribute Attribute Character
code 1 2 code
- -- - - -.
—lb’’e+lb’ta-t-lb’te -
3bytes (every 1 data)
4
Fig. 2-16. Line Buffer
The line buffer temporarily stores the data for one line using the format shown in Figure 2-16, and
also contains the command flags (1 6 bits), for attributes 1 and 2, for each character. The command
flags indicate what kind of command or mode is specified for the character. According to the
command flags, any of the EPSON ESC/P commands, NLQ, underline, emphasized character, and
font selection, is specified for the character.
When either the CPU detects a printing command (CR) or the line buffer becomes full, the printing
process (interrupt routine) is started.
The CPU transfers the character codes from the line buffer to the CG (Character Generator), and
transfers image data to the CG copy area. The CG copy area refers to the attribute flags in the line
buffer and expands the image data. The expanded data is then transferred to the image buffer.
The CPU writes the (vertical) dot patterns in the image buffer to port HD of the gate array (writes
MMIO, XX04H, and XX05H). At the same time, the CPU references the contents of the line buffer,
and outputs the FIRE signal (which corresponds to the dot patterns expanded in the image buffer)
to the gate array.
When the NLQ mode is selected, note the following difference from the Draft mode:
q During command analysis in step @, if the data is determined to bean NLQ character, the steps after
step @ are repeated two times for every one pass (NLQ requires two-pass printing).
When the download mode is selected, the following point is different from the draft mode:
q When referencing the CG in step @, the CPU accesses the down load buffer but not the CG.
2-21

REV.-A
2.4.4 Reset Circuit
A reset operation is performed when the INIT signal is input from the interface and when the printer
power is turned on. (Refer to Sections 1.4.6, 2.4.1, 2.4.2, and 2.4.3.1 for the reset operation.) Figure
2-17 shows the reset circuit.
E05A03 (3B)
R63
‘:;’’’”3’)+
INIT
A
C27
(CN2, Pin8) 470p
INIT
---- 1
I
l—
I RESI
I ~ - - - -
H
AND
D 4
I
I
I
I
I
/
L—---—
RESO
+ 5 + 2 4
+AJ--c3R43
ZD2
HZS1 5-3
24 47K
+-+
R42
+ D5 R34
IK
MA165 12K
C15
I p/5ov r
T
RESET (CPU, Pin 28)
*m(cN2pin’3)(lC)
Fig. 2-17. Reset Circuit
The I NIT signal from which noise is attenuated by R63 and C27 is input to the E05A03. The RESI terminal
of the E05A03 is connected to the power supply (+ 5 V and +24 V) reset circuit. When the printer power
is turned on, the level of the RESI signal is held at its threshold level or below (LOW level) until the voltage
of the +24 V line reaches the Zener voltage of ZD2 (when the power is turned off, the sequence
reverses). The same sequence is followed for the + 5 V line. The level of the RESI signal is held at its
threshold level or below (LOW level) until the voltage of the +5 V line reaches +5 V. In addition, the
level of the RESI signal is held LOW by R43 and C 15 for approximately 47 ms after the power supply
voltages become stable. The Schmitt trigger gate (CMOS level) at the input terminal of the RESI signal
shapes the analog waveform. The INIT and RESI signals are ANDed in the E05A03, then output from
the RESO terminal to the RESET terminals of the CPU and the interface board.
2-22

REV.-A
2.4.5 Carriage Motor
This section describes the sensor circuit, an outline of the firmware, and the drive circuit, which are
used to control the carriage motor. The specifications of the carriage motor are as follows:
Angle per step:
Number of steps per revolution:
Number of phases:
Excitation system and drive frequency:
Drive voltage:
Resistance per coil:
2.4.5.1 Home Position Sensor
7.5°
48 steps
Four
Unipolar drive, 2-2 phase excitation system (900 PPS)
Unipolar drive, 1-1 phase excitation system (450 PPS)
+24 VDC
41.5 ohms A7Y0
The home position sensor detects the reference position of the carriage. The sensor is located at the
home position which is to the left of the first column. Figure 2-18 shows the home position sensor circuit.
—.— —
+ 5
R 20
CN7 5.6K
I w - - HOME
1r
-
‘: 1
I
Home Position i
i
I
Sensor ~
1
I

1
L_ -d
2
Fig. 2-18. Home
R32
L3
IK
E05A03
(3B)
Position Sensor Circuit
When the carriage is at the home position, the reed switch is closed, and a LOW signal is input to the
HOME terminal of the E05A03. The CPU reads MMIO port XX 1 H of the E05A03 to determine when
the carriage is at the home position.
2-23

REV.-A
2.4.5.2 Carriage Motor Control
The carriage motor control system is an open-loop system. There are two basic phase switching speeds:
450 PPS (l-1 phase drive) and 900 PPS (2-2 phase drive), as shown below. The phase switching is
performed according to the time data (time required to switch a phase) which is determined by the
firmware, for the number of counts determined by the firmware. Figure 2-19 shows the basic phase
switching patterns.
CRA
CRB
CRC
CRD
Carriage *
Movement
-
Left
~ ‘ight
Left
Direction
~ ‘ight
(2-2 Phase Switching) (l-1 Phase Switching)
Fig. 2-19. Basic Phase Switching Patterns
Constant Speed
1
I
speed H.P. I
v IRt I I
I I I I
I Rt ,
I I I A
I
~ C. H.P.S ~ ~Printing
A
11
:START II
I
,
I
Area q
I
I
I
I
I
1
u
STOP
,-----
Drive
IMNv
- - - - - - - - - - - - - - - - - - - - - -
m ‘uLrLrl—
Hold
1
~ time
Fig. 2-20. Basic Operation Sequence
2-24

REV.-A
Figure 2-20 shows the basic sequence for the carriage operation.
q C. H.P.S. (Refer to Section 2.4.5.3)
When the printer is initialized, a carriage home position seek is performed. Then the carriage motor
enters the holding mode at the operation start position (START).
q Rt
At least 6 ms of rush time (Rt) is set just before acceleration and after deceleration to stabilize the
motor operation. It takes 75 ms for the carriage motor to restart from the stop mode.
q Acceleration mode
The acceleration mode consists of a maximum of 12 steps, and the time period for each step becomes
shorter as the step number increments. In the acceleration mode, the CPU checks the home position
signal each time the phase is switched, and a carriage error occurs if the home position signal goes
HIGH.
q .Ccmstant speed mode .
After acceleration completes, the carriage motor enters the constant speed mode. Printing is started
when the carriage motor enters this mode. The time period for each step is the same, 2.22 ms at
450 PPS and 1.11 ms at 900 PPS.
q Deceleration mode
The deceleration mode consists of a maximum of 12 steps. The time period for each step becomes
longer as the step number increments.
The 450 PPS speed (l-1 phase drive) is used for printing NLQ characters, and the 900 PPS speed (2-2
phase drive) is used for printing Draft characters. The patterns for the phase switching and the time
data are contained in the working area of the RAM. The CPU uses this data as a reference table, and
outputs the phase data to the E05A03 in accordance with the timing of the character to be printed.
(MMIO XX07H write operation)
2-25

REV.-A
2.4.5.3 Home Position Seek
Figure 2-21 shows the home position seek operation (actual carriage movement)
I
Held for 20 to 30 ms
according to the phase
data combination.
I
N
1
Moves from right to left for
four steps, then stops.
J J
Moves from left to right for
four steps, then stops.

f Moves from right to left until
it reaches the home position.
I
I Decelerates for five steps,
then stops. I
QA
Moves from left to right until
it leaves the home position.
1
+
Is this the Y
home position?
N,
I Decelerates for five steps,
then stops. I
N
1
Moves from right to left with
Y
a step time intewal of 10 ms
until it reaches the home
position.
I
I
Fig. 2-21 Home Position Seek Operation Flow
A home position seek is performed when the hardware is initialized. Because the carriage control is
an open-loop system, the CPU must perform a home position seek in order to get the carriage to a known
reference position. This operation is performed at 450 PPS (l-1 phase drive). The printing start position
(column 1) is 25 steps to the right of the home position. The carriage does not return to the home position
unless the printer power is turned off. When the carriage motor is in the acceleration mode or the normal
printing mode, the CPU checks the home position signal every time the phase is switched. If the CPU
detects that the carriage is at the home position, it regards this as a carriage error.
2-26

REV.-A
2.4.5.3 Carriage Motor Drive Circuit
Figure 2-22 shows the carriage motor drive circuit.
E05A03 I
R29
6
CRB
R30
CRC
5
R31
CRD 4
7b_D1843x4
+ 2 4 + 5J
3.3Kx4 ‘
(3B)
—
N5—
0--
6
Q -
2
+
5
-o-
1
R2
A
3.3K
CPU
1
,—,
:RA
;RB
ucRCOM
(2B)
Q19 3
B131 B
ciiCOM
EMO1 ZW 4
Fig. 2-22 Carriage Motor Drive Circuit
The carriage motor drive circuit is a constant voltage switching circuit (unipolar drive). When output
CR of the E05A03 is HIGH, the voltage is applied to the coil of the motor. When PAO of the CPU is HIGH,
the +24 V is applied to CRCOM (drive mode). When it is LOW, +5 V is applied to CRCOM (holding
mode).
2.4.6 Paper Feed Motor
This section describes the sensor circuit, an outline of the firmware, and the drive circuit, which are
used to control the paper feed motor. The specifications of the paper feed motor are as follows:
Angle per step: 7.5”
Number of steps per revolution: 48 steps
Number of phases: Four
Excitation system and drive frequency: Unipolar drive, 2-2 phase excitation system (480 PPS)
Drive voltage: +24 VDC
Resistance per coil: 58 ohms *7%
2-27

REV.-B
2.4.6.1 Paper End Sensor
The paper end sensor detects whether paper is present or not. Figure 2-23 shows the paper end sensor
circuit. + 5
1R4
5.6K
CN6
-27
(26)
2
Fig. 2-23. Paper End Sensor Circuit
When the paper runs out (of the detection area), the reed switch closes, and port PA5 of the CPU goes
LOW. The paper end detector is checked each time the phase is switched. The firmware controls the
following three operations:
q When a paper end is detected during printing, firmware stops printing and sets the printer OFF LINE.
q When a paper end is detected during initialization, firmware sets the printer OFF LINE.
q When the AUTO LOAD switch is pressed in the OFF LINE state: Firmware executes the auto loading
function (refer to Section 2.4.6.3) if paper is not already loaded or executes paper feeding (normally
one line) when the paper is loaded.
If the paper is loaded or ejected by pressing the FF or LF switch without executing printing, the printer
is not placed OFF LINE due to paper end detection.
Frame (L)
I
Paper
62.5mm
a
TApprox. 50mrn
JL
IFrame (R)
288mm
-
Fig. 2-24. Paper End Detection Area
2-28

REV.-A
2.4.6.2 Paper Feed Motor Control
The paper feed motor is controlled by an open-loop system just like the carriage motor. The basic phase
switching speed is 480 PPS (2-2 phase drive), and the phase switching is performed according to the
phase pattern stored in the firmware. Figure 2-25 shows the basic phase switching pattern.
PFA
PFB
PFC
PFD
Platen
Movement
B a c k _ Normal
Direction —
Fig. 2-25. Phase Switching Basic Pattern
Constant Speed
I
1
I
Speed
1
Power ON
1
1 STOP
I
r
1
I
I I
~Rtl ~
1 1
I I ; Rt2 ;
I
I 1
I
1
1
8
I
#
Drive ~---vuvu ----------Hold ~----%
Fig. 2-26. Basic Operation Sequence
2-29

REV.-B
Figure 2-26 shows the basic sequence for the paper feed motor.
q Rtl
When the printer power is turned on, the paper feed motor is rushed for 30 to 60 ms in any phase.
It takes 25 ms for the paper feed motor to restart from the stop mode. And after that, the paper feed
motor rotates both back and front for each 16 steps to fix the back-rush between the motor pinion
and gears.
q Acceleration mode
The acceleration mode consists of a maximum of four steps, and the phase switching time for each
step becomes shorter as the step number increments.
q Constant speed mode
After the acceleration completes, the motor enters the constant speed mode. The time period for
each step is the same, 2.03 ms.
. Deceleration mode
The deceleration mode consists of a maximum of 12 steps, and the phase switching time for each
step becomes longer as the step number increments.
q Rt2
When the paper feed motor decelerates and stops, it enters the holding mode after the rush time
of 15 ms.
The paper is fed 1/6 inch (4.23 mm) per 36 steps. When the total number of steps is 10 or less, the
paper feed motor is driven only in the constant speed mode, but with a step time of 3.28 ms. The phase
switching pattern and time data are contained in the working area of the RAM. The CPU outputs the
data to the E05A03 the number of times specified by the program. (MMIO XX06H write operation)
2.4.6.3 Auto Loading Function
The sequence for the auto loading function is shown below.
1. The printer moves the carriage to the 40th column.
2. The printer drives the paper feed motor for 433 steps to load the paper.
In this way, the printing start position is set approximately 22 mm from the top of the paper.
kApprox.
22mm 1st column
EPSON LX-800
Fig. 2-27. Printing Start Position
2-30

REV.-A
The auto loading function is valid under the following conditions:
q When the printer is OFF LINE.
q Just after the signal from the paper end sensor changes from LOW to HIGH. (The leading edge of
the signal is checked for.)
2.4.6.4 Paper Feed Motor Drive Circuit
Figure 2-28 shows the paper feed motor drive circuit.
I
E05A03
— .—
PFA
PFB
PFC
PFD
(3B)
CPU
PA2
CN5 A
12
al 7
“
I Q16 8
“
11
7
3.3K X 4
77!7 D1 8 4 3 x 4
+ 2 4 + 5
+J+”JL
RI
3.3K
3 4 ‘5
3
(lC)
5.6K
Q18
B1 093
J
R17
33
D3 9
10
(2B)
I
EMOIZW ~
Fig. 2-28. Paper Feed Motor Drive Circuit
The paper feed motor drive circuit is a constant voltage switching circuit (unipolar drive), which is the
same as the carriage motor drive circuit. When output port PF of the E05A03 is HIGH, voltage is applied
to the motor coil. When PA2 of the CPU is HIGH, +24 V is applied to PFCOM. When it is LOW, +5
V is applied to PFCOM.
2-31

REV.-A
2 . 4 . 7 Printhead
This section gives an outline of the software that controls the printhead, the drive pulse width control,
and the drive circuit. The specifications of the printhead are as follows:
Number of solenoids : Nine
Drive voltage : +24 VDC
Coil resistance : 19.2 ohms +10%
Printhead drive pulse width: 360 PS 10 ps (at 24 V, 25°C)
2.4.7.1 Printhead Control
The data is output to the printhead in the following sequence:
1.
2.
3.
4.
Print data is expanded in the image buffer as dot patterns. The CPU outputs the dot patterns to the
E05A03.
The data for pins 1 through 8 of the printhead is latched by HD 1 through HD8 of the E05A03. (MMIO
XX04H write operation)
The data for pin 9 of the printhead (usually for underlining) is latched by HD9 of the E05A03 via
DB7.
After latching the data, the printhead drive pulse width signal FIRE is output from the event counter
in the CPU. While the FIRE signal is LOW, the gate opens so that the data at HD 1 through HD9 is
output.
The timing of the event counter in the CPU is set mechanically. The data write operation is completed
within one cycle of the counter. The operation described below is inhibited to protect the printhead
from being damaged.
FIRE
Normal ~
Dot Pattern
Half
Dot Pattern
x
time ~
Fig. 2-29. Printhead Drive Pulse Pattern
Figure 2-29 shows the sequences for the normal and half dot printing, which can be performed at any
pin of the printhead. Driving the printhead continuously to print adjacent half dots (the portion marked
q in the above figure) is inhibited. If this pattern exists after expanding the image data, one dot will be
ignored.
2-32

REV.-A
2.4.7.2 Printhead Drive Pulse Width Control Circuit
In order to keep the value of the printhead drive pulse width constant, the CpU monitors the +24 VDC
line, the printhead common voltage, and uses the voltage level to adjust the width of the FIRE signal.
The printhead drive pulse width is controlled to be within the area shown by the oblique lines in Figure
2-Bn I 425!W.
=(n
CD
400
I
-.—
405
350
i
I 350 ;
I
I
I
I
I
I wYz////z
I I I 1
I
II
I
I
I
I
I
I
345
325
I I
I
1
I
I I
300
I I I
, 1 ,
21.6 24 26.4
Printhead Driving Voltage [V] ~
Fig. 2-30. Printhead Drive Pulse Width Range
+24V
R36
2.2K l/2W
VAref 4 2 4 )
+ 5 + 2 4
t
s=
*Wo
AVCC 43 ! ?!- -.-, .-.
I 7%
Fig. 2-31. +24 VDC Monitor Circuit
The CPU monitors the +24 V line at AN5 of the 8-bit analog to digital converter, computes the result,
and controls the drive pulse width of the signal (FIRE) output from the event timer. 4.7 V is applied to
reference voltage input VAref by ZD3, and the voltage obtained by dividing +24 V by R37 and R35
(approximately 4.08 V at +24.OV) is input to AN5.
2-33

REV.-A
2.4.7.3 Printhead Drive Circuit
Figures 2-32 and 2-33 show the printhead drive circuit and the waveform of the drive voltage.
CN4
+24V
Solenoid
Coil
Q1-Q9
C3293
HDn
E05A03
R52
I
(3B)
R61
IK
T
GP
Fig. 2-32. Printhead Drive Circuit
s.,e.oid..rre.t~::::;:Waveform
~A4:l- J
Drive Transistor
Collector Voltage
Waveform
.=approx. 360Ps
Fig. 2-33.
B=approx. 40ps C=approx. 1.11 ms
Solenoid Current and Drive Voltage Waveforms
2.4.8 Print Timing Control
This section describes the print timing control for the carriage and printhead and the bidirectional logic
seeking function.
2.4.8.1 Print Timing Control for the Carriage and Printhead
The phase switching of the carriage motor and the printhead driving are controlled by the CPU, and
the relationship between the two is shown in Figure 2-34.
2-34

REV.-A
.—
FIRE
1 1
HD1
,,;,,
HD2
,
1;
H~~ ~
—
HD8
HD9
HD1 -8 (H) 41 22 14 08 14 22 41 00 00...
HD9 (H) 80 80 80 80 80 80 80 80 00 . . . . .
Fig. 2-34. The Relationship Between the Carriage and Printhead Control Signals
Figure 2-34 shows the relationship between the carriage and the printhead when character “~” is
printed in the Draft mode. The dot data of HD 1 through HD8 and HD9 synchronizes with the LOW level
of ~. The phase switching for the carriage motor is performed asynchronously with the application
of the drive voltage to the printhead. A delay time (Dt) of 46 psec. in the Draft mode (900 PPS) and
92 psec. in the NLQ mode (450 PPS) is used in order to protect the +24 V line from being overloaded.
Printing for one line is performed in the sequence described above. In the NLQ mode, half of the dot
pattern is printed for one line, the paper is fed for 1/216 inch, and the remaining half of the dot pattern
is printed. In the half speed mode (valid when the printing speed is 900 PPS), the printhead drive pulse
width is doubled (720 Ps) and the carriage drive speed is halved (450 PPS).
2.4.8.2 Bidirectional Logic Seeking
The bidirectional logic seeking is controlled by the CPU. The CPU starts printing after expanding the
print data. However, the processing of the next group of data is started while printing the former group.
In this way, the CPU can determine the carriage return position for the next group of data so that the
carriage can be moved the shortest distance before printing the next line. Figure 2-35 shows this
operation.
2-35

REV.-A
1.
2.
3.
4.
D
E P S O N f
@ @) --N;;:
LINE1
@
@l@
: T E R M INA L
@
LINE2
@
b @
I
I
Carriage Operation
(Constant Speed)
Carriage Operation
(Acceleration/Decelerat ion]
Paper Feed Operation
This is Draft mode printing
4,,1,1 ~
PR INT E R ~~
@
@ ~;
LINE3 I
@
1 2 3 4 5 10 15 1+
----(column )
+ -

11--Printing Area
Acceleration Area
Home PositIon
1-3: Printing of the 1st line
4-5: Logic seeking
6: Paper feed
7-9: Printing of the 2nd line
10: Paper feed
1 1-12: Printing of the 3’rd line
Fig. 2-35. Logic Seeking
Upon receive in print data “EPSON” for a line from the host computer, the printing is performed in
an action of @ to @ with the carriage and printhead moving to position Q.
The CPU, receiving the next data from the host computer, analyzes it and determines the acceleration
start position of the carriage.
In an action of @ to @, the carriage is moved to position @, here paper feed is operated @. Then
the carriage goes through acceleration printing and deceleration @,@, @to position Q, next paper
feed is operated @.
In an action of @ to @, acceleration, printing, and deceleration are performed ~.
2-36

REV.-A
2.5 PRINTER MECHANISM OPERATION
The printer mechanism includes sensors, the carriage, the paper feed, and the ribbon feed mechanism.
Figure 2-36 shows an external view of the printer mechanism.
Fig. 2-36. Printer Mechanism External View (Model-3A10)
2.5.1 Sensor Mechanism
This subsection describe the two sensor mechanisms:
Home Position Sensor
home position sensor and paper end sensor.
The home position sensor functions to determine the home position of the carriage, and sends a
reference signal for print start position. The home position sensor mechanism consists of the
mechanical switch which is operated by lever at the bottom of the frame. When the detection pIate
pushes the lever of sensor, the mechanical switch closes.
Paper End Sensor
The paper end sensor detects the presence/absence of paper. The paper end sensor mechanism
consists of a mechanical switch which is operated by paper end sensor Iever. When the paper supply
has run out, the mechanical switch closes.
2-37

REV.-B
2.5.2 Carriage Mechanism
The carriage mechanism includes the printhead, the carriage, the timing belt, the carriage motor, and
the platen. Fig. 2-37 shows the carriage mechanism.
The timing belt is connected into the bottom of the carriage. This belt is driven by the carriage motor
and moved via the belt driven pulley. The printhead is mounted on the carriage, and the entire unit is
moved right and left along the carriage guide shaft and plate.
Left
v z Carriage Guide Shaft
: Driving Pulley
Fig. 2-37. Carriage Mechanism
2-38

REV.-B
Printhead
The dot wire operation during printing is as follows: when the head driving coil for a dot wire is
energized, the actuating plate engaged with the dot wire at one end is attracted to the iron core and
drives the dot wire toward the platen. The dot wire strikes the ribbon and the paper against the platen
to print a dot in the paper.
When the head driving coil is deenergized, the actuating plate returns to the initial position as a result
of the action of the actuating plate spring. After striking the platen, the dot wire also returns to its initial
position as a result of impact energy and from the wire resetting spring, and the dot wire is held in
engagement with the actuating plate until it is driven again.
Fig. 2-38 shows the printhead printing operation.
Platen
Dot Wire Ribbon Mask
— Wire Resetting Spring
Stopper
(]
Actuating Plate
-
Paper
Act~ating Plate Spring
Fig. 2-38. Printhead Printing Operation
2-39

REV.-B
2.5.3 Paper Feed Mechanism
The paper feed mechanism operates by friction feed method for cut sheets, and roll paper, and by the
sprocket feed method for fanfold paper.
2.5.3.1 Friction Feed Operation
The paper is held against the platen by two paper feed rollers and by the printer cover. At this time,
the paper feed motor is driven to rotate the platen gear, via the paper feed reduction gear, in the direction
shown in Figure 2-39. The rotation of the platen Gear feeds the paper in the direction of the arrow due
to friction from the paper feed rollers and platen.
Because the paper is held against the platen by the spring force of the paper feed rollers, the paper
can be released by shifting the paper release lever forward.
Paper Feed Motor
Fig. 2-39. Friction Feed Operation
2-40

REV.-B
2.5.3.2 Sprocket Feed Operation
When the printer is using the sprocket feed method, the holes in the paper are set over the sprocket
pins along the sprocket wheel.
The paper feed motor is driven to rotate the gears, via the pinion on the shaft of the motor, in the direction
shown in Figure 2-40. Rotating the gears rotates the sprocket wheels, which advances the paper in
the direction shown by the arrow.
For the sprocket feed method, the pressure of the paper feed rollers against the platen is released by
shifting the release lever forward.
—
ar
Motor
Fig. 2-40. Sprocket Feed Operation
2-41

REV.-B
2.5.4 Ribbon F e e d M e c h a n i s m
The ribbon feed mechanism consists of the ribbon cartridge and the ribbon feed
I driving gearalways turns counterclockwise, via the geartrains shown in Table 2-6,
direction of the timing belt.
Table 2-6 Ribbon Feed Gear Train
section. A ribbon
irrespective of the
Direction of Movement of Carriage Gear Train
Left to right (arrow q ) Belt driven pulley ~ Planet gear (1) +
Planet gear (2) + Ribbon driving gear
Right to left (arrow ~) Belt driven pulley ~ Planet gear (1) ~
Planet gear (3) ~ Planet gear (4) ~
Ribbon driving gear
Figure 2-41 shows ribbon feed mechanism. The inked ribbon is inside the cartridge case in an endless
state, held between the ribbon feed and ribbon pressure roller mounted on the ribbon driving gear.
The rollers are driven by the movement of the gear, and the inked ribbon is fed.
A ribbon breaking spring is attached at the exit of the cartridge case to prevent the ribbon from slacking.
A ribbon mask is installed for preventing the ribbon from staining the paper.
Ribbon Feed Roller L
‘kRibbon ‘
ressure
‘O’’er
Ribbon Transmission Gear W
‘ane””w
Ribbon Driving Gear
Ribbon
riage
Breaking
Spring
Fig. 2-41. Ribbon Feed Mechanism
2-42

REV.-A
CHAPTER 3
OPTIONAL EQUIPMENT
3.1 GENERAL ......................................................................................................3-1
3.2 OPTIONAL INTERFACES ........................................................................3-1
LIST OF TABLES
Table 3-1. Optional Interfaces .......................................................................3-1
3-i

REV.-A
3.1 GENERAL
This chapter describes the options available for the LX-800.
3.2 OPTIONAL INTERFACES
The LX-800 use the 8100 series optional interfaces. The optional interfaces are listed in Table 3-1.
Table 3-1. Optional Interfaces
Cat No. Description
RS-232C
Buffer Size Flag Control
X-ON/OFF Max. Bit Rates
Current Loop Control (BPS)
q 8 143 None o 0 19200
8145 2K o x 9600
8148 2K/8K o 0 19200
IEEE-488
Buffer Size Function
Listen Only Address
(G P-IB) Operation Operation
8165 2K/8K AH, L, DC o 0
Special Application
Interface
8133W APPLE 11, using 8K-byte ROM
o . . . . . Available x . . . . . Not available
q When the #8 143 is used in LX-800, serial/parallel conversion is available only following conditions.
Baud rate: 75 to 9600 bps
Handshaking: DTR or X-ON/OFF control
NOTE: Refer to the “Optional Interface Technical Manual” for details.
3-1

REV.-A
D
4.1
4.2
4.3 a
CHAPTER 4
ISASSEMBLY, ASSEMBLY, AND
ADJUSTMENT
GENERAL REPAIR INFORMATION ..................................................4-1
DISASSEMBLY AND ASSEMBLY .....................................................4-3
4.2.1 Removal of Printhead ................................................................4-3
4.2.2 Removal of Cases........................................................................
4.2.2.1 Upper Case Removal .......................................................
4.2.2.2 Control Panel (LCPNL Board) Removal . . . . . . . . . . . . . . . . . . . . . 4-5
4.2.3 Removal of Electric Circuit Boards .......................................4-5
4.2.3.1 ROCX Board Removal “–.....................................................4-5
4.2.3.2 ROC Filter Unit Removal ...............................................4-6
4.2.4 Removal of Printer Mechansim ..............................................4-7
4.2.4.1 Removal of Platen Unit and Paper Guide . . . . . . . . . . . . . . . . 4-7
4.2.4.2 Removal of Printer Mechanism ...................................4-8
4.2.5 Disassembly of Printer Mechanism ......................................4-9
4.2.5.1
4.2.5.2
4.2.5.3
4.2.5.4
4.2.5.6
4.2.5.6
4.2.5.7
4.2.5.8
4.2.5.9
Paper Feed Mechanism Removal ................................ 4-9
Removal of Paper Feed Motor .....................................4-12
Removal of Paper End Sensor......................................4-12
Disassembly of Platen Unit ..........................................4-13
Removal of Carriage Unit ..............................................4-13
Removal of Carriage Motor ..........................................4 1 6
Removal of Home Position Sensor ............................. 4 1 7
Disassembly of Ribbon Feed Mechanism . . . . . . . . . . . . . . . . 417
Disassembly of Tractor Unit.........................................4 1 8
4.3.1 Platen Gap Adjustment.............................................................4 2 0
4-i

—
LIST OF FIGURES
Fig. 4-1
Fig. 4-2.
Fig. 4-3.
Fig. 44.
Fig. 4-5.
Fig. 4-6.
Fig. 4-7.
Fig. 4-8.
Fig. 4-9.
Fig. 4-10.
Fig. 4-11.
Fig. 4-12.
Fig. 4-13.
Fig. 4-14.
Fig. 4-15.
Fig. 4-16.
Fig. 4-17.
Fig. 4-18.
Fig.4-19.
Fig. 4-20.
Fig. 4-21.
Fig. 4-23.
Fig. 4-24.
Fig. 4-25.
Fig. 4-26.
Fig. 4-27.
Fig. 4-28.
Fig. 4-29.
Fig. 4-30.
Fig. 4-31.
Fig. 4-32.
Fig. 4-33.
Fig. 4-34.
Fig. 4-35.
Fig. 4-36.
Printhead Removal ......................................................................4-3
Upper Case Removal-l ..............................................................
Upper Case Removal-2 ..............................................................
Control Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-5
ROCX Board Removal ...............................................................4-6
ROC Filter Unit Removal ..........................................................4-6
Printer Mechanism Removal ...................................................4-7
Platen Unit Removal ..................................................................4-7
Printer Mechanism Rear View ...............................................4-8
Printer Mechanism Removal ...................................................4-8
Removal of Paper Guide Plate Releae Lever . . . . . . . . . . . . . . . . . . . . . 4-9
Removal of Release Lever ........................................................4-9
Removal of Paper Feed Roller Shaft .................................... 4-1o
Removal of Paper Guide Plate and Spacer . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Paper Guide Plate and Spacer Assembly Points . . . . . . . . . . . . . 4-11
Paper Release Lever and Paper Guide Plate
Release Lever Assembling Point............................................4-11
Removal of Paper Feed Motor ................................................4-12
Removal of Paper End Sensor ................................................4-12
Platen Unit Assembling Point ................................................4-13
Printer Mechanism Bottom View ..........................................4-13
Removal of Carriage Guide Shaft Ground Plate . . . . . . . . . . . . . . 4-14
Removal of Carriage Guide Plate ..........................................4-15
Carriage Guide Shaft and Head Adjust Lever . . . . . . . . . . . . . . . . . . 4-15
Carriage Motor Frame Removal .............................................4-16
Removal of Carriage Motor .....................................................4-16
Removal of Home Position Sensor........................................4-17
Ribbon Gear Cover Removal ...................................................4-17
Removal of Side Cover ..............................................................4-18
Removal of Sprocket Guide Shaft.........................................4-18
Paper Guide Roller Removal and Attaching ........................4-l 9
Sprocket Wheel Attaching ......................................................4-19
Removal of Ribbon Mask .........................................................4-20
Platen Gap .....................................................................................4-21
Carriage Guide Shaft Lever Movement............................... 4-21
Platen Gap Adjustment Positions .........................................4-21
4-ii

REV.-A
LIST OF TABLES
Table 4-1. Repair Tools ....................................................................................4-1
Table 4-2. Measuring Instruments...............................................................4-1
Table 4-3. Abbreviations List of Small Parts ...........................................4-2
Table 44. Form and Abbreviated Part Name of Screw . . . . . . . . . . . . . . . . . . . . . . . 4-2
4-iii

REV.-B
4.1 GENERAL REPAIR INFORMATION
This chapter describes the disassembly, assembly, and adjustment procedures for replacing any of the
main components of the LX-800.
DANGER
q Prior to beginning the disassembly, assembly, and adjustment procedures, be sure to disconnect
the AC power cord.
q When assembling, disassembling, and adjusting the printer, wear gloves to protect your hands
from being cut by the printer mechanism or an edge of a plate, such as the ground plate.
WARNING
q The printer mechanism, the various boards, and other parts are sometimes held without screws
by plastic clips. When removing these units be careful not to damage the plastic clips.
The tools and measuring instruments listed in Tables 4-1 and 4-2 are recommended for use when
disassembling and repairing the printers.
— .—
Table 4-1. Repair Tools
Description
Brush No. 1
Brush No. 2
Cleaning Brush
Round nose pliers
Diagonal cutting nipper
Tweezers
Electric soldering iron
E-ring holder #2.5”
E-ring holder #5
Phillips screwdriver No. 2
Screwdriver No. O
Thickness gauge (0.47 mm)
Type
o
0
0
0
0
0
0
0
0
0
:
Part No.
B74 1400200
B74 1400100
B74 1600100
B7404OO1OO
B7405OO1OO
B64 1000100
B740200 100
B740800400
B740800700
B743800200
B743800300
B776701 201
NOTES: 1. The tool marked q is used when attaching the E-ring (2.3 mm).
2.0 = Commercially available tool
3. @ =
EPSON exclusive tool
Table 4-2. Measuring instruments
Description Specification Class
Oscilloscope 50 MHz A
Tester A
Slide calipers A
Multi meter B
Logic Analyzer B
NOTE: A = Mandatory, B = Recommended
After printer disassembly, assembly, and adjustment, be sure to perform lubrication, adhesive
application, cleaning, and maintenance as indicated in Chapter 6, in order to maintain optimal printer
performance.
4-1

REV.-A
All small parts are described by abbreviations.
Table 4-3. Abbreviations List of Small Parts
Abbreviation Part Name
Cs Cup Screw
CP Cross-recessed head machine screw (Pan head)
CPO C.P. screw with Outside toothed lock washer
CP (P) C.P. screw with Plain washer
CPSP Cross-recessed head machine screw Spring washer
and Plain washer assemblies (Pan head) —
CTC Cross-recessed head Tapping screw (Cup screw)
CTB Cross-recessed head Tapping screw (Bind)
CTB (P) C.T.B. screw with Plain washer
CTBS (0) C.T.B (S tight) screw with Outside toothed lock
washer
CTPS (0) C.T.P. (S tight) screw with Outside toothed lock
washer
CTPS (P) C.T.P. (S tight) with Plain washer
Table 4-4 describes the relationship between the form and the abbreviated part name of screw.
Table 4-4. Form and Abbreviated Part Name of Screw
Heed Body Washer
(~bled)
1.~ross–recessed head 1.Bind 1 .~ormal 1.~lain washer
@ b (5J(-j)a
@ 2.~ap tight
?. SLotted head (with Notch)
~tight
—
o
2.@tside toothed
lock washer
e
2.~an
m
~ Q@
3.@p
@
3.~apping 3.~pring washer
4.~russ
lnIIBEJo Q@
@ ma
4-2

REV.-A
4.2 DISASSEMBLY AND ASSEMBLY
This chapter describes disassembly of the LX-800. Assembly can be performed by simply reversing
the order of disassembly, with special notes for assembly mentioned as “ASSEMBLY POINTS.” For
assembly and disassembly procedures which require adjustment, the necessary adjustment is indicated
as “ADJUSTMENT REQUIRED.” After assembly and disassembly, perform the necessary adjustment
as indicated.
WARNING
. Read Section 4.1 (GENERAL REPAIR INFORMATION) before disassembly.
. Remove paper and the ribbon cartridge before disassembly.
The disassembly sequence of this section is grouped into five parts:(1) removal of printhead, (2) removal
of cases, (3) removal of the electric circuits boards, (4) removal of printer mechanism unit, and (5)
disassembly of printer mechanism.
Ref~to Figures A- 16 through A- 18, the LX-800 exploded diagrams and the printer mechanism exploded
diagram.
4.2.1 Removal of Printhead (Figure 4-1)
1. Remove the printer cover, and confirm that the paper and the ribbon cartridge have been removed.
2. Unlock the two levers securing the printhead to the carriage, by pulling them down, and lift the
printhead to remove it.
Print
Fig. 4-1. Printhead Removal
3. Disconnect the head cable from the connector on the printhead.
4-3

REV.-A
4.2.2 Removal of Cases
This section describes the upper case and control panel (LCPNL) removal.
4.2.2.1 Upper Case Removal (Figures 4-2 through 4-3)
1.
2.
3.
Remove the sheet guide unit, printer cover, tractor unit, and paper guide.
Insert a standard screwdriver into the two holes at the front of the lower case, unlock the notches,
then lift the upper case.
Upper Case Guide
~--y-
The notch can be unlocked
by pushing it in the direction
shown by the arrow, using
the screwdriver.
Case Notch
Fig. 4-2. Upper Case Removal - 1
While lifting the upper case, disconnect the FPC of the control panel (LCPNL) from connector CN3
on the ROCX board, and remove the upper case.
Fig. 4-3. Upper Case Removal -2
4-4

REV.-A
4.2.2.2 Control Panel (LCPNL Board) Removal (Figure 4-4)
1. Remove the upper case. (Refer to Section 4.2.2.1)
2. Turn the upper case over, push the two notches securing the control panel to the upper case
inward, and remove the control panel from the upper case.
WARNING
When mounting and removing the control panel, be careful not to damage the FPC of the control
panel with the FPC guide of the upper case.
/7
c
Guide
Fig. 44. Control Panel Removal
4.2.3 Removal of Electric Circuit Boards
This section describes the ROCX board and ROC filter unit removal.
4.2.3.1 ROCX Board Removal
2. Disconnect connectors CN5, CN4, CN6, CN7, and CN8 on the ROCX board, which connect each
component to the ROCX board.
WARNING
When disconnecting the connectors, pull them out slowly while holding the board. The board could
be damaged if the connectors are pulled out roughly.
4-5

REV.-A
Fig. 4-5. ROCX Board Removal
3. Remove the C.T.C. screws (M3 x 6) securing the ROCX board to the base plate.
4. Loosen the six bent tabs of the lower case, which secure the ROCX board to the lower case, using
a screwdriver, and remove the ROCX board.
WARNING
When removing the ROCX board from the lower case, do not bend the tabs too far. Be careful when
pushing the tabs so as not to break them or damage the components on the ROCX board.
4.2.3.2 ROC Filter Unit Removal (Figure 4-6)
2. Disconnect the cable connecting the ROC filter unit to the ROCX board from connector CN8 on the
ROCX board.
Fig. 4-6. ROC Filter Unit Removal
4-6

REV.-A
3. Remove the five screws securing the ROC filter unit to the base plate.
The screws are as follows:
1 X C.B.O. (M4 X 8)
1 X C. T. B.S.(O) (M4 X 8)
2 X C.T.B. (M4 X 14
1 X C. T. P.S.(O) (M3 X 6)
4. Remove the ROC filter unit (including the AC cable (120 V), AC inlet (220/240 V), and power switch).
4.2.4 Removal of Printer Mechanism
This section describes the platen unit, paper guide, and printer mechanism removal. Before removing
the printer mechanism, remove the platen unit and the paper guide so that the printer mechanism can
be removed quickly and easily.
Fig. 4-7. Printer Mechanism Removal
4.2.4.1 Removal of Platen Unit and Paper Guide (Figures 4-8 through 4-9)
1. Remove the upper case. (Refer to Section 4.2. 1.1)
2. Turn the shaft holders at the left and right sides of the platen unit as shown in Figure 4-8, and lift
the platen unit to remove it.
a. Push the shaft holder outward using a screwdriver.
b. Turn the shaft holder counterclockwise.
/
Frame
/
(Left Side)
ten
‘Shaft Holder
Fig. 4-8. Platen Unit Removal
4-7

REV.-A
3. Disconnect the cable from connector CN6 on the ROCX board.
4. Unlock the two notches of the paper guide by pushing them frontward from the back side of the
printer mechanism, and remove the paper guide.
Fig. 4-9. Printer Mechanism Rear View
ADJUSTMENT REQUIRED
If any problems occur (such as non-uniform print density) after removing and installing the platen
unit or replacing the platen unit with a new one, perform the following adjustment.
q 4.3.1 Platen Gap Adjustment
4.2.4.2 Removal of Printer Mechanism (Figure 4-10)
1.
2.
3.
-
Remove the platen unit and the paper guide. (Refer to Section 4.2.4.1.)
Disconnect the cables from connectors CN5, CN4, and CN7 on the ROCX board. (Refer to Figure
4-5.)
Loosen the six tabs of the lower case, which secure the printer mechanism to the lower case, by
pushing them with a screwdriver. The printer mechanism can be removed easily using the following
procedure:
WARNINGI
When loosening the tabs, be sure to push them softly so as not damage the lower case or printer
mechanism.
Fig. 4-10 Printer Mechanism Removal
4-8

REV.-A
a. Loosen tabs @) and @, and lift the left side of the frame 1 cm from the lower case.
b. Loosen tab @ and lift the left side of the frame 5 more cm from the lower case.
c. Slide the printer mechanism in the direction shown by the arrow in Figure 4-10 to remove it from
tabs @ and @. Use tab @ as a fulcrum.
4.2.5 Disassembly of Printer Mechanism
This section describes the removal of each component from the printer mechanism. Refer to Figure
A-1 8, the Printer Mechanism Exploded Diagram, and Table A-16, “Component Name List”.
4.2.5.1 Paper Feed Mechanism Removal (Figures 4-11 through 4-16)
1. Remove the printer mechanism. (Refer to Section 4.2.4)
2. Push the notch of the paper guide plate release lever, and pull the paper guide release lever and
the paper guide release shaft to remove them.
—
%
per Guide Plate
/
Frame (Left Sid lease Shaft
Paper Guide
Plate Release
Lever
Push
Fig. 4-11. Removal of Paper Guide Plate Release Lever
3. Push the notch of the paper guide plate release lever from the inside of the frame, and remove the
release lever.
lease L
rame
Notch
Fig. 4-12. Removal of Release Lever
4-9
.*-

REV.-A
4. Push the paper feed roller shaft down, slide it approximately 2 cm to the left, and lift it to remove
it.
Frame
/
Fig. 4-13. Removal of Paper Feed Roller Shaft
5. Loosen the four tabs securing the paper guide plate and the paper guide plate spacer to the frame,
using a screwdriver, and lift them to remove them. (Push the tabs out from the frame.)
Fig. 4-14. Removal of Paper Guide Plate and Spacer
4-1o

REV.-A
ASSEMBLING POINTS:
1. When reassembling the paper guide plate and the paper guide spacer, refer to Figure 4-15 for the
mounting direction.
-.—
$:1 I . Paoer Guide Plate SDacer
.’7 h-fl F o r w a r d + - 11 II
~ The side containing.—
the cutout is the
right side.
(Viewed from front of Printer Mechanism)
Fig. 4-15. Paper Guide Plate and Spacer Assembly Points
2. When installing the paper release lever and the paper guide plate release lever, carefully observe
the mounting positions shown in Figure 4-16.
Paper Release Lever
Paper Guide Plate Release Lever
Paper Guide Plate Release Shaft
B
(Viewed from left side of Printer Mechanism)
Fig, 4-16. Paper Release Lever and Paper Guide Plate Release Lever Assembling Point
. The paper release lever and the paper guide plate release lever must be joined at point A, and the
paper guide plate release shaft and a section of the paper guide plate release shaft must be joined
at point B, as shown in the figure above.
4-11

REV.-A
4.2.5.2 Removal of Paper Feed Motor (Figure 4-17)
2. Disconnect the motor cable from the paper feed motor.
3. Loosen the tab of the frame, which secures the paper feed motor to the frame, by pushing it using
a screwdriver, and remove the paper feed motor by turning it in the direction shown by the arrow
below, using point A as a fulcrum.
/
I Paper Feed
(Viewed from upward)
Motor
(Viewed from left side)
Fig. 4-17. Removal of Paper Feed Motor
4.2.5.3 Removal of Paper End Sensor (Figure 4-18)
1.
2.
Remove the platen unit and paper guide. (Refer to Section 4.2.4.1)
Loosen the tab securing the paper end sensor to the paper guide, remove the paper end sensor by
turning it in the direction shown by the arrow below, using point A as a fulcrum.
Notch
(Cross section of Paper Guide)
Fig. 4-18. Removal of Paper End Sensor
4-12

REV.-B
4.2.5.4 Disassembly of Platen Unit (Figure 4-19)
1. Remove the platen unit. (Refer to Section 4.2.4.1)
2. Remove the left shaft holder and the paper feed knob from the platen unit.
3. Pull out the platen gear at the right side of the platen unit.
4. Remove the five E-rings from the platen, and pull out the right shaft holder and the flat spring.
ASSEMBLY POINT:
When reassembling the platen unit, refer to Figure 4-19 to install the flat spring and the shaft holder
correctly, and insure that the gap between the platen and the platen gear is adequate.
Flat Spring
, Platen
.—
Platen Gear
—
Fig. 4-19. Platen Unit Assembling Point
4.2.5.5 Removal of Carriage Unit (Figures 4-20 through 4-24)
1.
2.
3.
Remove the printer mechanism. (Refer to Section 4.2.4)
Remove the printhead and disconnect the head cable.
Turn the printer mechanism over, and manually move the carriage unit over to the cutout in the
carriage motor frame. (Move the carriage unit so that the joint of the carriage unit and the timing
belt can be seen through the cutout.)
Fig. 4-20. Printer Mechanism Bottom View
4-13

REV.-A
4. Detach the timing belt from the carriage unit using round nose pliers.
Be careful not to damage it.
5. Lift portion A of the carriage guide shaft ground plate to remove it from the notch in the carriage
motor frame, and slide
portion B of the plate).
the plate so that it can be removed from the
Carriaga Guide
Shaft Ground.
frame (through the cutout at
18
A /
Plata
74
“orFrame +’
%.*
Fig. 4-21. Removal of Carriage Guide Shaft Ground Plate
6. Place the printer mechanism face up. Turn the left carriage guide shaft lever fully counterclockwise
and pull it out through cutout A. Then turn the right carriage guide shaft lever fully clockwise, and
pull it out the same way as the left lever.
Frame
A
Carriage Guide
Shaft Laver (Left) _ h%)Q.
I

(Viewed from Left Side)
Fig. 4-22. Removal of Carriage Guide Shaft
4-14

7.
—.
8.
Push the notch of the frame, which secures
carriage quide plate to the left to remove it.
REV.-A
the carriage guide plate to the frame, and slide the
al
Plate
— —
Fig. 4-23. Removal of Carriage Guide Plate
Lift the carriage unit, carriage guide shaft, and head adjust lever to remove them.
ASSEMBLING POINTS:
1. Before installing the carriage guide shaft and the head adjust lever, position them as shown in Figure
4-24.
v%Head Adjust Lever
“D” cut
.
Carriage Guide Shaft
Fig. 4-24. Carriage Guide Shaft and Head Adjust Lever
2. The colors of the left and right carriage guide shaft lever are gray and black, respectively. The hole
in each lever must slide onto the corresponding end of the shaft.
3. When connecting the head cable, pass it correctly through the FPC guide at the frame.
ADJUSTMENT REQUIRED
When the carriage unit is reassembled, perform the following adjustment.
q 4.3.1 Platen Gap Adjustment
4-15

REV.-A
4.2.5.6 Removal of Carriage Motor (Figures 4-25 through 4-26)
1. Perform steps 1 to 5 of Section 4.2.5.5.
2. Disconnect the motor cable from the carriage motor. Disconnect the lead wire of the home position
sensor from the molded clip at the bottom of the frame. (Refer to Figure 4/-25.)
3. Loosen the four tabs securing the carriage motor frame to the chassis frame, using
and remove the carriage motor frame.
i + —%
Tab
Tab
Fig. 4-25. Carriage Motor Frame Removal
4.
5.
a screwdriver,
Remove the belt tension spring from
ring on the carriage motor side, then
holder, belt pulley and timing belt.
the carriage motor frame. Remove the E type (3.2) retaining
remove the plain washer, belt pulley flange, belt pulley shaft
%3’”
Retaining Ring E type (3.2)
Plain Washer
e

Belt Pulley Frange
v
o Belt Pulley Shaft Holder
Belt Pulley
,
*

Carriage Motor Frame
Q
Carriage
Motor x*
Belt Tension
%
Spring
Fig. 4-26. Removal of Carriage Motor
Move the carriage motor in the direction shown by the arrow to remove it.
4-16

REV.-B
ASSEMBLY POINT:
Attach the E-rings as follows:
q When attaching a ring to the left pulley shaft, set it so that its opening faces to the left.
. When attaching a ring to the right pulley shaft, set it so that its opening faces to the right.
Confirm that the attached retaining rings do not move, using the tweezers.
4.2.5.7 Removal of Home Position Sensor (Figure 4-27)
1. Perform steps 1 to 3 of Section 4.2.5.6 to remove the carriage motor frame.
2. Push the notch of the home position sensor, and remove the home position sensor from the carriage
motor frame.
—
Fig. 4-27. Removal of Home Position Sensor
4.2.5.8 Disassembly of Ribbon Feed Mechanism (Figure 4-28)
1.
2.
3.
Remove the printer mechanism. (Refer to section 4.2.4)
Turn the printer mechanism over, and loosen the four bent tabs of the ribbon gear cover using a
screwdriver. (At this time, just loosen the tabs slightly but do not remove the ribbon gear cover. If
it is removed before the printer mechanism is turned over, the gears will be scattered.)
Tab
(Printer mechanism bottom view)
Fig. 4-28. Ribbon Gear Cover Removal
Place the printer mechanism face up, and lift the ribbon gear cover to remove it.
4-17

REV.-A
4.2.5.9 Disassembly of Tractor Unit (Figures 4-29 through 4-32)
1.
2.
3.
4.
Loosen the three tabs of the sprocket mounting plate using a screwdriver and remove the side cover.
(Both the left and right side covers can be removed at the same time.)
Push
Sprocket
Mounting
Plate (R) Side Cover (R)
Transmission Gear
Fig. 4-29. Removal of Side Cover
Remove the sprocket gear and the sprocket transmission gear.
Remove the shaft holder. (Refer to Figure 4-8. The left and right shaft holders can be removed at
the same time.) Remove the sprocket shaft from the sprocket mounting plate.
Loosen the sprocket mounting plate tab using a screwdriver, and pull out the sprocket guide shaft.
Sprocket Guide
Shaft
Fig. 4-30. Removal of Sprocket Guide Shaft
4-18

5.
REV.-B
Pull out the sprocket assembly and the paper guide roller from the sprocket shaft and the sprocket
guide shaft. When pulling out the paper guide roller, move it along the sprocket shaft toward the
side with the T-shaped notch. (When assembling the paper guide roller, insert the sprocket shaft
from the side with the T-shaped notch.)
Sprocket Shaft
opaper Guide Roller’
—
Fig. 4-31. Paper Guide Roller Remova~and Attaching
ASSEMBLY POINTS:
1.
2.
Attach the paper guide roller to the sprocket shaft from the direction indicated in Figure 4-31.
Attach the sprocket wheel to the sprocket shaft so that the sprocket wheel marks are on the left
side and so that the marks on the two wheels line up.
Sprocket Wheel
/
Shaft
er portion
side.)
goes on
Marks to be matched
Fig. 4-32. Sprocket Wheel Attachment
4-19

REV.-A
4.3 ADJUSTMENT
This section describes the adjustment procedures required for reassembling the LX-800 printer. When
disassembly or replacement is performed during maintenance or repairs of the parts described in this
section, the following
4.3.1 Platen Gap
The gap between the
adjustments should be performed to ensure proper operation.
Adjustment (Figures 4-33 through 4-36)
platen and the printhead should be adjusted when the carriage guide shaft or
carriage guide shaft levers are rotated or removed, or the printing is abnormal.
2. Install the paper guide and the platen unit on the printer mechanism.
3. Remove the printhead, then remove the ribbon mask using tweezers. When removing the ribbon
mask, pull it frontward slightly, then lift it.
G
/
Ribbon Mask
Carriage
Fig. 4-33. Removal of Ribbon Mask
4. Reinstall the printhead.
5. Set the head adjust lever at the nearest position to the platen.
6. Manually move the carriage to the paper-end sensor lever position (column 10).
7. Insert a thickness gauge (0.47 mm) between the platen and the printhead, and adjust the left and
right carriage guide shaft levers so that the gap becomes 0.47 + 0.02 mm. When the thickness
gauge starts to slip down due to its own weight, the gap adjustment is adequate. If the 0.49 mm
thickness gauge cannot be inserted and the 0.45 mm one can be inserted easily, the gap adjustment
is adequate.
WARNING
When setting the position of the carriage guide shaft lever, be sure that both tabs A and B do not
enter the notch at the same time. It is designed so that tab B may not enter when tab A is inside,
and that tab A may not enter when tab B is inside.
4-20

REV.-A
0.47 * 0.02 mm
~ - t l -
.—
Printhead
T–
Platen
Fig. 4-34. Platen Gap
t Lever
Frame (Left side)
Carriage Guide
Shaft Lever (Left)
Fig. 4-35. Carriage Guide Shaft Lever Movement
Carriage guide shaft (left): Turned clockwise - The platen gap widens.
Turned counterclockwise - The platen gap narrows.
Carriage guide shaft (right): Turned clockwise - The platen gap narrows.
Turned counterclockwise - The platen gap widens.
Perform the above adjustment at the 10th and 70th column positions, and at the middle of the platen.
When the gaps at all three positions match, the adjustment is complete.
,’v?,?la
Fig. 4-36. Platen Gap Adjustment Positions
4-21

REV.-A
5.1
5.2
5.3
Fig.
Fig.
Fig.
CHAPTER 5
TROUBLESHOOTING
GENERAL ...................................................................................................5-1
UNIT
UNIT
5.3.1
5.3.2
5-1.
5-2.
5-3.
REPLACEMENT ............................................................................5-3
REPAIR ............................................................................................5-11
ROCX Board ..................................................................................5-11
Printer Mechanism .....................................................................5-14
LIST OF FIGURES
Table 5-1.
Table 5-2.
Table 5-3.
Table 54.
Table 5-5.
Table 5-6.
Table 5-7.
Troubleshooting Procedure ........................................................5-1
Special Tools for LX-800 ............................................................. 5-2
Printhead Resistance ................................................................... 5-1o
LIST OF TABLES
Special Tools for LX-800 .........................................................5-2
List of Units .................................................................................5-3
Symptom and Reference Pages ............................................5-3
ROCX Board Parts List ............................................................5-11
ROCX Board Unit Repair.........................................................5-14
Printer Mechanism Parts List................................................5-14
Printer Mechanism Unit Repair ............................................5-15
5-i

REV.-B
5.1 GENERAL
The difficulty in troubleshooting is that error symptoms vary, depending on the defective component.
However, troubleshooting may be accomplished more easily by following the process shown in Figure
5-1. This flowchart shows the two levels of repair: one is unit replacement, in which the defective
subassembly is identified and replaced; and the other is component isolation and repair.
F
Troubleshooting
Unit replacement
— Electric Printer
circuit mechanism
QElectric circuit
G
Printer mechanism
unit repair unit repair
Fig. 5-1. Troubleshooting Procedure
‘ARN’NG~q Read section 4.1 (GENERAL REPAIR INFORMATION).
5-1

REV.-B
For troubleshooting, repair tools are listed in Tables 4-1 and 4-2. In addition, EPSON has prepared the
following specified tools to increase the work efficiency and safety:
Fig. 5-2. Special Tools for LX-800
Table 5-1. Special Tools for LX-800
No. Name Description Part No.
o #E626 Extension cable between the ROCX (CN5) B765 107901
and motors.
@ #E524 Connector board and extension cable be- B765 105201
@ #E523
tween the ROCX (CN4) and a printhead.
B765 105101
0 #E594 Extension cable between the ROCX (CN6) B765 105401
and a paper end sensor.
Extension cable between the ROCX (CN7)
and a home position sensor
@ #E201 Extension cable between the ROCX (CN8) B777603801
and a ROC Filter unit.
5-2

REV.-A
5.2 UNIT REPLACEMENT
The unit replacement procedure is based on symptom analysis. According to the particular symptom
found by the multimeter, the units listed in Table 5-2 need to be replaced.
Table 5-2. List of Units
Unit Name Description Unit Code No.
Fuse (Fl) 125V/1 .25A (for 120V) X50206 1050
250VI0.63A (for 220/240V) X502063030
ROC Filter Unit 120V version Y565503000
120V 2 plugs version Y565507000
220V version Y565504000
240V version Y565505000
ROCX board unit Control board Y565201 000
LCPNL board unit Control panel Y565501OOO
Model-3A10 I printer mechanism I Y565590000
Table 5-3 shows the flow chart to be referred to depending on the symptoms.
Table 5-3. Symptom and Reference Pages
Symptom Problem Indicators
Reference
Page
Printer Does Not Operate . No indicator on the control panel lights.
with Power Switch ON . Carriage does not move.
5-4
Abnormal Carriage . Carriage moves away from home position ‘at power ON.
Operation . Although the carriage returns to the home position, the 5-5
printer does not enter READY mode.
Incorrect Printing (in self- . No printing is executed.
test) with Normal Carriage q Some dots do not appear. 5-6
Operation
Abnormal Paper Feed . No paper is fed.
. Separation between lines varies with irregular paper feed.
5-7
Abnormal Operation of . No paper is fed (by operation of the LF or FF switch) in
Control Panel OFF-LINE mode.
. No operation mode is set from the control panel.
5-8
. ON-LINE or OFF-LINE mode is not obtained.
Incorrect Printing in ON . Carriage operates normally at power ON and the result of
LINE Mode the self-test is correct. However, the print data from the 5-9
computer is not output normally.
5-3

REV.-A
(1) Printer does not operate when power switch is on.
1 on the ROC Filte
Y
Measure the output voltage
from ROC Filter unit.
Refer to Table 2-2.
Replace the ROC Filter
unit.
Replace the printer
mechanism.
*
vEND
T7END
5-4

(2) The carriage does not operate correctly.
connectors CN4, CN5,
CN6 and CN7, connecting the
ROCX board and the printer
mechanism, inserted securel I
I secure connectors.
I
Y
N
-
—
*
END
N Replace the printer
mechanism.
Y
N
d
Y
‘vEND
5-5

REV.-B
(3) The carriage operates normally, but the self-test printing is incorrect.
I
Set the gap-adjustment lever
at the side nearest the platen
Measure the printhead
resistance. See Figure
5-3. Page 5-10
N a
Y
Replace the printhead.
I
N
1
Y
Replace the printer
mechanism.
A.‘the printer mechanism and the ROCX board-
N -
Replace the ROCX
‘t board.
v1
QReinsert them
correctly.
u
T)END
/7END
5-6

(4) The self-test printing is normal, but the paper is not fed
YSTART
—
Set the paper correctly.
Y
Replace the printer
turned manually with mechanism.

Y
$’+
Replace the printer
mechanism.
END
END
N
Replace the ROCX board.
*
END
5-7

REV.-A
(5) The control panel does not operates correctly.
T
START
CN3 between the contro Reinsert connector CN3
panel and the ROCX board
Y
N
*
Y
Y
Replace the control panel.
*
END
Replace the ROCX circuit
board.
N
Y
q
I
board..
q
1
Replace the control
panel.

(6) The printing is incorrect in the ON-LINE mode.
NOTE: It is assumed that the host computer operates normally.
Y
START
1
Perform test printing.
*
N Refer to other troubleshoot-
ing items.
. —
Y
interface board
Replace the optional
interface board.
Standard Parallel N
Iq
I
eEND
Replace the connection
cable from the host com-
puter.
N
Y
/7
I
board.
END
5-9

REV.-A
Printhead
(Terminal assignment )
o #l
() # 2
o # 3
o # 4
o i#5
O X6
o # 7
O # 8
o # 9
( Wire assignment)
Coil Resistance:
19.2 1.9 Q at 25°C
(Between each dot wire and common.)
Fig. 5-3. Printhead Resistance
5-1o

REV.-A
5.3 UNIT REPAIR
This section indicates possible causes and checkpoints for different symptoms. The checkpoints include
waveforms and resistance values for normal operation. By referring to the checkpoints, determine the
detective component and perform the proper repair. Tables 5-5 and 5-7 have the following five columns:
. Problem: Identify the problems listed in this column.
q Symptom: Check symptoms against those given in this column.
q Cause: Check problems against the causes listed in this column.
. Checkpoint: Use the instructions given in this column for troubleshooting.
q Solution: Make repairs according to the instructions given in this column.
5.3.1 ROCX B o a r d
Table 5-4 shows the main components of the ROCX Board. The unit repair procedure for the ROCX
board is described in Table 5-5.
.— —
Table 54. ROCX Board Parts List
Location I Part Name I Description I Part No.
F2 I Fuse I 125V, 3.15A, UL, CSA I X502084020
Q21
Q25
Q1 - Q9
2SD1832C4 60V, 5A, 20W X3021 83209
2SD1833C4 60V, 7A, 25W X302 183309
2SD1647C3 5V, IOOmA, 700mW X302 164709
3A
1 c, 2C
4C
SRI
2B
3B
ZD1
ZD2
ZD3
pPc494c Switching Regulator IC X440064940
7407 Hex. Buf. Drv. O.C. X4201 OOO7O
@D4364C Static RAM X4001 43644
PPC78L05J Switching Regulator IC X440078054
/.LPD7810HG CPU X400078 101
E05A03 Gate array Y448800001
HZS20-2TD 20 ~0,5V, 150mA, 400mW X3301 60309
HZS 15-3TD 15 AO.5V, 150mA, 400mW X3301 60209
HZS4.7NB2- 1 TJ 4.7 ~0.5V, 150mA, 400mW X3301 60109
5-11

REV.-A
Table 5-5. ROCX Board Unit Repair
Problem
The printer does
not operate at all.
(The power lamp
on the control
panel does not
light.)
q The l/F cable is
disconnected.
Cause Checkpoint SolutionSymptom
The +24V DC Check fuse (Fl) on the
ROC Filter unit.
Replace F1.ROC filter unit is
defective.line is dead.
Measure the output volt-
age of ROC filter unit. Re-
fer to Table 2-2.
Measure the resistances
of R21 and R66.
R21: 3160
R66: O.1f-1
Replace the ROC
filter unit.
Replace the R21
or R66
Resistors are
open.
Replace the
IC3A, Q25, Q24,
or Q23.
Measure the wave-form
of IC3A or Swithcing
transistors. Refer to Fig-
ure 2-9.
Switching regula-
tor IC or Switching
transistors are
defective.
Measure the voltage of
IC3A Pin 8.
(Pin 8 = 20VDC)
Replace the IC3A
or Q22.
Fuse (F2) is open. Check fuse on the ROCX
board.
Replace F2.
Replace SR1,
Q20, or Q21.
Measure the waveform of
SR1 and Q21.
The +5V DC
line is dead.
Switching regula-
tor IC SR1 or
switching transis-
tors are defective.
Resistor is open. Measure the resistance
of R13.
R13: 2Q
Replace R13.
Reset circuit is
dead.
+24V, +5V line is
defective.
Check the +24V, +5V
line.
Gate array (36) is
defective.
The ROM is
defective.
The Gate array is
defective.
Check the level of IC3B
Pin 25.
In operating: High
Replace Gate ar-
ray (3 B).
The printer
mechanism
does not initial-
ize at power on.
Check the pin insertions
of ROM.
Check the level of IC3B
Pin 25.
In operating: High
Replace ROM
[3 C).
Replace Gate ar-
ray (3 B).
5-12

REV.-A
Table 5-5. ROCX Board Unit Repair (Cent’d)
Problem Symptom Cause Checkpoint Solution
The printer does Buzzer rigns 5 Home position Check the level of IC3B Replace Gate ar-
not operate. (The times. sensor is Pin 23. ray (3 B).
power lamp on the defective. Carriage at the home
control panel position: LOW
lights.)
. The l/F cable is
+24V line is Check the +24V line.
disconnected.
abnormal.
In self-test mode, Carriage control Phase switching is Measure the wave-form Replace the re-
printing is is abnormal. abnormal. of transistors Q12, 13, fective transistor
abnormal 16, 17 collector. Refer to (or IC3B).
Figure 2-19.
Common voltage Check the voltage of Replace Q19 (or
switching is transistor Q19 emitter. IC2B).
defective. In driving: +24V
In holding +5V
.— Paper feed con- Phase switching is Measure the wave-form Replace the de-
trol is abnormal. abnormal. of transistors Q 10, 11, fective transistor
14, 15 collector. Refer to (or IC3B).
Figure 2-25.
Common voltage Check the voltage of Replace Q18 (or
switching is transistor Q 18 emitter. IC2B).
defective. In driving: +24V
In holding: +5V
A specific dot is Printhead drive is Observe the high/low If there are not
missing. defective. change at HDn (Pin 55 - high/low
63) of the IC4B and at changes, replace
collector of transistor Qn. IC3B. Otherwise,
replace any de-
fective
,..,c%i ~ transistors.
“n”~
5-13

REV.-A
5.3.2 Printer Mechanism
If trouble occurs with the printer mechanism, troubleshoot it as described in Table 5-7.
Refer to sections 4.2 Disassembly and Assembly and 4.3 Adjustment for replacement and adjustment
of parts. If the same problem or symptom persists, check other items in the cause column and try again.
Table 5-6 lists the recommended parts to keep in stock for repairing the printer mechanism. The location
numbers given in this table correspond to the numbers shown in Figure A-1 7.
Table 5-6. Printer Mechanism Parts List
Location No.
402
413
416
417
418
430
444
446
448
Part Description I Part No.
Frame
Paper Feeding Roller Spring
Home Position Sensor
Carriage Motor
Timing Belt
Paper End Sensor
Head Cable
Paper Feed Motor
Printhead
F333OO1O1O
F322253020
F333053000
F33305 1010
F33305 1020
F333252000
F333003080
F3330031 10
F4201OOOOO
5-14

REV.-A
Table 5-7. Printer Mechanism Unit Repair
Carriage motor The carriage Foreign substances Move the timing belt Remove any fore-
does not operate. motor does not are lodged in the manually and check if ign substances.
operate at all at gears or the carriage motor
power ON. mechanism. rotates.
The carriage mo- Measure the coil resis- Replace the car-
ter is defective. tance of the motor. riage motor.
. Resistance value:
Approx. 41.50 k 7%
(25”C)
Carriage does not The carriage Defective belt driv- Check for broken or q Replace the
operate normally motor rotates, en pulley assem- worn pulleys. belt driven pul-
at power ON. but the carriage bly, or belt driving Iey assembly.
(When the power does not move. pulley on the shaft q Replace the
is turned on with of the carriage carriage motor.
the carriage manu- motor.
ally moved to its
The timing belt is
cenTer position.)
Checkthat timing belt is Reinsert the tim-
defective. inserted correctly into ing belt.
the bottom of the
carriage.
Check if the timing belt Replace the tim-
is broken. ing belt.
The carriage Carriage movs- Check if the carriage Clean and
moves left ment is not moves smoothly when it lubricate.
slightly and smooth. is moved manually.
stops.
Check if the tension of Replace the belt
the timing belt is too tension spring.
high.
Buzzer rings 5 The home position Use an oscilloscope to Replace the
times. sensor is check the output home position
defective. waveform. sensor.
Printing is not per- The carriage The common Check the connector for . Replace the
formed in Self- moves, but wires of the head the common wires of the printhead
Test. printing is not cable are head cable. cable.
performed at disconnected. q Replace the
all.
The contact of the Check the connector con-
printhead.
head cable continuity of the head cable.
nectors is poor.
The common Check the continuity of
wires of the head the common wires in the
cable are head cable.
disconnected.
Printing stops The paper guide Verify that the paper Reset the paper
before the end plate is not in the guide plate is mounted in guide plate.
of a page. right postion. the right position.
The paper guide is Verify that the paper Replace the pa-
weak. guide is effective. per guide plate.
5-15

REV.-A
Table 5-7. Printer Mechanism Unit Repair (cent’d)
Checkpoint Solution
Reset the ribbon
cartridge.
Replace the
printhead.
Replace the head
cable.
Symptom Cause
The ribbon car-
tridge is installed
incorrectly.
Problem
A specific dot is
not printed.
Check that the ribbon
cartridge is installed
correctly.
Printing is
abnormal.
Check the continuity of
the printhead.
The printhead is
disconnected.
Check the continuity of
the head cable.
Measure the coil resis-
tance of the printhead.
See Fig. 5-3.
q Resistance value:
19.2 Q A 10%
The head cable is
disconnected.
The printhead is
defective.
Replace the
printhead.
Verify that the dot wire is
not broken.
Replace the
printhead.
Insert the print-
head or head ca-
ble firmly.
Verify that the printhead
or head cable is firmly in-
serted into the
connector.
A dot is occa-
sionally not
printed.
The printhead or
head cable is not
connected
correctly.
Clean and
reconnect,
Check for foreign objects
in the head cable
connector.
The printhead is
defective.
The printhead is
defective.
Verify that the tip of the
dot wire is not worn.
Verify that the tip of the
dot wire is not worn.
Replace the
printhead.
Replace the
printhead.
The overall
printing color is
light, or the
printing density
is not uniform.
The paper thick-
ness lever is not
set at the correct
position.
The ribbon life is
completed.
Check that the set posi-
tion of the paper thick-
ness lever is proper for
the paper.
Perform a visual check.
Place the lever in
the right
position.
Replace the rib-
bon cartridge.
The platen gap is
not properly
adjusted.
Perform adjust-
ment according
to Section 4.3.1
“Platen Gap
Adjustment”.
The printing is
misaligned dur-
ing bidirectional
printing.
The timing belt
tension is not cor-
rect, or defective.
Verify that the timing belt
is inserted firmly into the
carriage.
Check if the timing belt
is loose.
Reinsert the tim-
ing belt firmly.
Replace the belt
tension spring.
5-16

REV.-A
Paper does not q Sheet load- The paper end Verify that the switch Replace the pa-
feed correctly. ing mecha- sensor is clicks when the paper per end sensor.
nism does defective. end sensor lever is
not operate. approached.
. Printing is
The paper release Verify that the paper re-
performed,
Place the lever in
but the paper
lever is not in the lease lever is in the right the right
right position.
is not fed.
position. position.
Foreign substances Perform a visual check of Remove any for-
are caught in the the paper path. eign substances.
paper path.
The paper feed Verify that no foreign . Remove the
motor does not substance is lodged be- foreign
drive the gear tween the gears and that substance.
correctly. the gears are not broken . Replace the
or worn. defective gear.
The paper feed Mea%iure the coil resis- Replace the pa-
motor is defective. tance of the paper feed per feed motor.
motor.
. Resistance value: 58Q
794
The paper feed The backlash be- Check the backlash. Replace the pa-
quantity is not tween the paper per feed reduc-
uniform. feed motor and tion gear.
the paper feed re-
duction gear is not
correct.
Paper does not The paper is Phases of the right Verify that the marks on Refer to Section
feed correctly. fed aslant. and left sprocket the right and left sprock- 4.2.3.9 “Tractor
assembly do not et assembly are at the Unit
match. same position. Disassembly”.
Ribbon feed is The ribbon The ribbon car- Verify that the ribbon is Replace the rib-
da fective. does not feed. tridge is defective. fed when the ribbon car- bon cartridge.
tridge is dismounted and
the knob is rotated manu-
ally in the direction of
the arrow.
Foreign substances Verify that the ribbon q Remove any
are caught in the drive gear rotates when foreign
gears, or the gear the carriage is moved substances.
is worn. manually to right and q Replace the
left. defective gear.
. Lubricate.
The ribbon is The planetary le- Verify that the planetary Replace the belt
fed only when ver in the car- Iever turns in reverse and driven pulley
the carriage tridge holder is engages with the gear assembly.
moves to the defective. when the carriage is
right (or to t h e moved manually to the
left). right and left.
5-17

REV.-A
Problem Symptom Csuse Checkpoint Solution
Ribbon feed is The ribbon feed The ribbon slips Verify that the ribbon is Replace the rib-
defective. quantity is not inside the ribbon fed when the ribbon car- bon cartridge.
uniform. cartridge. tridge is dismounted and
the knob is rotated manu-
ally in the direction of
the arrow.
Paper becomes The paper be- The ribbon mask Verify that the ribbon Reset the ribbon
stained. comes ink is in the incorrect mask is in the correct mask.
stained where position. position.
printing is not
The paper thick- Check that the set posi- Place the lever in
performed.
ness lever is not tion of the paper thick- the right
set at the correct ness lever is proper for position.
position. the paper.
The platen gap is Perform adjust-
not properly ment according
adjusted. to Section 4.3.1
“Platen Gap
Adjustment”.
Printing is per- Printing does The paper end Verify that the switch Replace the pa-
formed after the not stop after sensor is clicks when the paper per end sensor.
end of the paper the end of the defective. end sensor lever is
or without paper. paper. approached.
5-18

REV.-A
CHAPTER 6
MAINTENANCE
6.1 PREVENTIVE MAINTENANCE ...............................................................6-1
6.2 LUBRICATION AND ADHESIVE APPLICATION ............................. 6-1
LIST OF FIGURES
Fig. 6-1
Fig. 6-2
Tabla 6-1.
Table 6-2.
Table 6-3.
Correct Adhesive Application.......................................................6-2
LX-800 Lubrication Points .............................................................6-3
LIST OF TABLES
Lubricants and Adhesive ............................................................ 6-1
Lubrication Points ......................................................................... 6-2
Adhesive Application Points ..................................................... 6-2
6-i

REV.-B
6.1 PREVENTIVE MAINTENANCE
Proper maintenance is essential to maintain optimal printer performance for the longest possible period
and to minimize malfunction frequency. Preventive maintenance includes regular cleaning of the case
exterior, using alcohol, and occasional vacuuming of the mechanism interior to remove dust and paper
particles. Following cleaning, refer to Section 6.2 to verify that the unit is adequately lubricated. Before
returning the serviced printer to the consumer, inspect the springs, paper feed rollers, and the basic
operation of the unit.
WARNING
Disconnect the printer from the power supply before performing maintenance. Do not use thinner,
trichloroethylene, or ketone-based solvents on the plastic components of the printer.
6.2 LUBRICATION AND ADHESIVE APPLICATION
EPSON recommends that the points illustrated in Figure 6-2 be lubricated at the points listed in Table
6-2with EPSON O-2 and G-27, which have been tested for compliance with the needs of this printer.
(Refer to Table 6-1 for details about O-2 and G-27.) Be sure that the parts to be lubricated are clean
before applying lubricant, and avoid excessive application, which may damage related parts.
Adhesive application is necessary at the point indicated in Table 6-3 when the pan is disassembled
or replaced. EPSON recommends Neji lock #2 (G) adhesive be applied to the point diagramed in Figure
6-1. Avoid overflow of excess to related parts.
Table 6-1. Lubricants and Adhesive
Classification Description Capacity Availability Parts No.
Oil o-2 40 cc @ B7 10200001
Grease G-27 40 gm @ B702700001
Adhesive Neji lock #2 (G) 1000 gm @ B730200200
@: EPSON-exclusive product
6-1

REV.-A
Table 6-2. Lubrication Points (Refer to Figure 6-2)
INOTE: Lubrication is necessary in the process of assembly.
Ref. No. Lubrication Points Lubricent
(1) Carriage guide shaft. (On the both left and right sides of o-2
carriage.)
(2) Carriage guide plate. (Contact portion with the carriage. 50 mm G-27
(L) X 2 mm (W))
(3) Platen gear. (Quarter of gears circle.) G-27
(4) Shafts that sets the ribbon gears. G-27
(5) Gear portions of the ribbon gears. G-27
(6) Felt ring (inside of the carriage) o-2
Table 6-3. Adhesive Application Point (Refer to Figure 6-l.)
Adhesive Application Point No. of Point
Engaging part between timing belt and carriage. 1
To Timing Belt
Fig. 6-1. Correct Adhesive Application
6-2

REV.-A
Fig. 6-2. LX-800 Lubrication Points
6-3

REV.-A
APPENDIX
A.1 PRINCIPAL IC SPECIFICATIONS .....................................................A-1
A.1.l wPD781OHG (CPU) ....................................................................A-2
A.1.2 E05A03BA (E05A03CA) Gate Array ...................................A-7
A.1.3 2064C CMOS S-RAM ...............................................................A-9
A.1.4 494 Regulator..............................................................................A-1 O
A.1.5 7407 .................................................................................................A12
A.2 SCHEMATICS AND DIAGRAMS ......................................................A-1 3
LIST OF FIGURES
Fig. A-1. pPD781 0/781 1 Pin Diagram .................................................A-2
Fig. A-2. 1.LPD7810/7811 Block Diagram ............................................A-3
Fig. A-3.
Fig. A-4.
Fig. A-5.
Fig. A-6.
Fig. A-7.
Fig. A-8.
Fig. A-9.
Fig. A-10.
Fig. A-1 1.
Fig. A-1 2.
Fig. A-1 3.
Fig. A-14.
Fig. A-1 5.
Fig. A-1 6.
Fig. A-17.
Fig. A-18.
Fig. A-1 9.
OP Code Fetch Timing ..............................................................A-6
Memory Read Timing ................................................................A-6
Memory Write Timing ...............................................................A-6
E05A03BA (E05A03CA) Pin Diagram ................................A-7
E05A03BA (E05A03CA) Block Diagram ............................A-8
2064C Pin Diagram ...................................................................A-9
2064C S-RAM Block Diagram .................................................A-9
494 IC Pin and Block Diagrams ............................................A-1 O
494 Dead Time and Feedback Control ...............................A-1 1
7407 Pin Diagram ......................................................................A-1 2
LCPNL Circuit Diagram ............................................................A-1 3
ROCX Board Circuit Diagram ................................................A-1 5
ROCX Board Component Layout ..........................................A-1 7
LX-800 Exploded Diagram .......................................................A-1 9
Printer Mechanism Model-3Al O Exploded Diagram . . . . . . A-20
Model-3Al O Tractor Unit Exploded Diagram . . . . . . . . . . . . . . . . . . . A-21
LX-800 Case Outline Drawing ...............................................A-22
A-i

REV.-A
LIST OF TABLES
Table A-1. Primary ICS on the ROCX Board .......................................A-1
Table A-2. PPD781O Mode Setting .......................................................A-4
Table A-3. ~PD7811 PF Operation ........................................................A 4
Table A-4. wPD781O PF Operation ........................................................A-4
Table A-5. KPD7810/7811 Port Functions .........................................A-5
Table A-6. 2064C Truth Table .................................................................A-9
Table A-7. 494 IC Port Functions ...........................................................A-1 O
Table A-8. Connector CN1 Pin Assignment .......................................
Table A-9. Connactor CN2 Pin Assignment .......................................
Table A-1 1. Connector CN4 Pin Assignment .......................................
Table A-16. Parts No. Reference Table...................................................
A-1 6
A-1 6
A-1 6
A-1 6
A-1 6
A-1 6
A-1 6
A-1 6
A-18
A-ii

REV.-A
A.1 PRINCIPAL IC SPECIFICATIONS
This chapter describes the principal ICS used in LX-800. The ICS are shown in Table A-1.
Table A-1. Primary ICS on the ROCX Board
I Location No. ICs Nmne I Part Code No. I
2B pPD7810HG X400078 101
3B E05A03 Y448800001
4C 2064C X4001 43644
3A pPc494c X440064940
1 c, 2C 7407 X4201 OOO7O
A-1

REV.-B
A.1.l PPD781OHG ( C P U )
The 7810 (78 11 ) HG has the following differences from the conventional G type.
(a) Driving oscillation frequency is guaranteed up to 15 MHz.
(b) Reference voltage AVref (A/D converter reference voltage) is different.
For point (b), the multiplier for the AVref terminal’s peripheral circuit is different. Therefore, a board
with the HG type can use only HG type replacement parts. (The G type cannot be substituted.)
The PPD78 10/781 1 is an 8-bit CPU that includes two 8-bit timer counters, an 8-bit A/D converter, 256
bytes of RAM, and a serial interface. A system can be constructed easily using this IC. The main features
of this IC are as:
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
256 bytes of built-in RAM (addresses FFOOH - FFFFH)
4096 bytes of mask ROM (addresses O - OFFFH) for the 7811 CPU
Direct addressing of up to 64K bytes
8-bit A/D converter
158 instructions
1 KS instruction cycle
16-bit event counter
Two 8-bit timer counters
3 external and 8 internal interrupts; 6 priority levels and 6 interrupt addresses
General purpose serial interface (asynchronous, synchronous, and 1/0 modes)
1/0 line (78 1 1: 40-bit 1/0 port; 78 10: 24 bit edge detection, 4 inputs)
Zero cross detection
Standby function
Built-in clock pulse circuit
NMOS
Figures A-1 and A-2 illustrate the 78 10/781 1
its functions.
PAO
PA 1
PA2
PA3
PA4
PAS
PA6
PA7
PBO
PB1
PB2
PB3
PB4
PB5
PB6
PB7
Pco
Pc 1
PC2
PC3
PC4
PC5
PC6
PC7
m
INT 1
microprocessor,
m
I
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
;:
25
60
59
%
56
55
54
53
;?
50
49
48
47
46
45
44
43
42
41
40 I
and Tables A-2 through A-5 describe
Vcc
VDIY
PD7
PD6
PD5
PD4
PD3
PD2
PO 1
PDO
PF7
PF6
PF5
PF4
PF3
PF2
PF 1
PFO
ALE
~
RD
A VC C
VAREF
AN7
AN6
AN5
AN4
AN3
AN2
A N ]
ANO
AV SS
Fig. A-1. pPD7810/7811 Pin Diagram
A-2

[
PORTF
H PORTD
II
PORTC
I
11’oflo
m m m
0
PORTB
11
PORTA
I
In
2

‘zn

z
aw
1-
Z—
—
In 1
1
—
ID
x’
uQ
.
v
a
Fig. A-2. wPD7810/7811 Block Diagram
A-3

REV.-A
Table A-2. PPD781O Mode Setting
Mode 1 Mode O External memory
o 0 4K Byte Addresses O to OFFFH
o 1 (Note) 16K Byte Addresses O to 3FFFH
1 (Note) 1 (Note) 64K Byte Addresses O to OFEFFH
NOTE: Pull-up is made.
Table A-3. KPD7811 PF Operation
PF7 PF6 PF5 PF4 PF3
Port Port Port Port Port
Port Port Port Port AB1 1
Port Port AB 13 AB 12 AB 11
I AB 15 AB14 AB 13 AB 12 AB 11
PF2 PF1 PFO External Memory
Port Port Port 256 Bytes (max.)
AB1O I AB9 I AB8 I 4K Bytes (max.) I
AB1O I AB9 I AB8 I 16K Bytes (max.) I
AB 10 AB9 AB8 64K Bytes (max.)
I
Table A-4. ~PD7810 PF Operation
MODE 1 MODE O PF7 PF6 PF5 PF4 PF3 PF2 PF1 PFO External Memory
o 0 Port Port Port Port AB 11 AB 10 AB9 AB8 4K Bytes
o 1 Port Port AB13 ABI 2 AB 11 AB1O AB9 AB8 16K Bytes
1 1 AB15 AB 14 AB 13 AB12 AB1 1 AB1O AB9 AB8 64K Bytes
A-4

REV.-A
Table A-5. APD7810/7811 Port Functions
Pin Signal Direction Description
1 - 8 PAO -7 In/Out Poti A. Eight-bit 1/0 with output latch. 1/0 possible by mode A
(MA) register. Output HIGH.
9 - 1 6 PBO - 7 In/Out Poti B. Eight-bit 1/0 with output latch. 1/0 possible by mode B
register (MB). Output HIGH.
1 7 - 2 4 Pco - 7 In/Out Port C. Eight-bit l/O with output latch. Port/control mode can be
set by mode control C (MCC) register. Output HIGH.
25 NMI In Non-maskable interrupt of the edge trigger (trailing edge).
26 INT 1 In Maskable interrupt input of the edge trigger (leading edge). Also
used as the AC input zero cross detecting terminal.
27, 29 MODE 1, 0 In/Out 781 1: O = LOW and 1 = HIGH
7810 modes set in accordance with external memory (see Table
A-2).
28 RESET In LOW reset
-m 31 x2, xl — Crystal connection for built-in clock pulse. When clock pulses are
supplied externally, input must be to Xl.
32 Vss . Supply voltage, Vss, OV
33 AVSS — Analog Vss
3 4 - 4 1 ANO - 7 In Eight analog inputs of the A/D converter. AN7 -4 can be used
as the input terminals to detect the leading edge and to set the
test flag upon detection of the trailing edge.
42 VAref In Reference voltage
43 AVCC — Analog Vcc
44 m out Read strobe. LOW at the read machine cycle and at reset, HIGH
at other times.
45 WR out Write strobe. LOW during the write machine cycle and at reset,
HIGH at other times.
46 ALE out Address latch enable. Latches the lower 8 address bits to access
external memory.
4 7 - 5 4 PFO -7 Port F
781 1: Port bit-by-bit 1/0 possible by mode F register. In exten-
sion mode, gradual address output assignment is possible in
accordance with the size of external memory. See Table A-3.
78 10: By setting modes O and 1, assignment to the address bus
(AB 15 - 8) can be made in accordance with the size of the
external memory. The remaining terminals can be used as 1/0
ports. See Table A-4.
5 5 - 6 2 PDO -7 Port D.
781 1: Port bit-by-bit 1/0 possible.
In extension mode, PD7-O act as the multiplexed address/data
bus (AD7-0).
78 10: Multiplexed address/data bus to access external memory.
63 Voo — Supply voltage, Vm, +5V
64 Vcc — Supply voltage, Vcc, +5V
A-5

REV.-A
. CPU Timing (Figures A-3 through A-5)
Three oscillations define one state. The OP code fetch requires four states: during T1 to T3, program
memory is read; instructions are interpreted during T4. Address bus lines 15 - 8 are output from TI
to T4. Address bus lines 7 - 0 (PD7 - O) are used in the multiplex mode; the address is latched during
T1 at the ALE signal. Since the memory addressed is enabled after disengaging the driver (AD7 - O),
~ is output from T1 - T3, fetched at T3, and processed internally at T4. The ALE and ~ signals are
executed from T1 - T3; the OP code fetch for these two signals is performed at T4. The WR signal
is output from the middle of T1 to the beginning of T3. The address and ALE timing is the same as
that for memory read; however, following address output bus lines AD7 -0 (pD7 - O) are not disabIed,
and write data is output at AD7 - 0 at the beginning of T1 and the end of T3.
NOTE: When lines PD7 - 0 are set to the multiplexed addressldata bus (AD7 - O), and PF7 -0 to
the address bus (AB7 - O), the ~ and WR signals in the machine cycle are high when memory
is not being accessed.
CLOCK
ALE
AB15 -8
(PF7 -O)
AD7 - 0
(PD7 -O)
m
/
Y ADDRESS x
x ADDRESS }-- -- OP CODE ---c
Fig. A-3. OP Code Fetch Timing
T1 T2 T3
CLOCK
AB15 -8
(PF7 -O) x ADDRESS x
AD7 - 0
(PD7 -O) x A D D R E S S }- -- { READ DATA ---
c
‘~
Fig. A-4. Memory Read Timing
CLOCK
AB15 -8
(PF7 -O) x ADDRESS x
AD7 - 0
(PD7 -O) x ADDRESS Y x WRITE DATA x
‘~
Fig. A-5. Memory Write Timing
A-6

REV.-A
A.1.2 E05A03BA (E05A03CA) Gate Array
The E05A03BA gate array intergrates many CPU peripheral functions, so that fewer chips are required
to construct a complete system. Figure A-6 shows the E05A03BA pin diagram, and Figure A-7 shows
the E05A03BA block diagram. The details of the E05A03BA are given in section 2.4.2.
Vcc 1 Vcc
NLOLP ~ ~ 2 63 ~ --HD 1
—
3
4
5
6
7
6
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
62 ~ ---HD2
61 ~ --HD3
60 4 --HD4
59 ~ --HD5
58 –
4 --HD6
57 ~ --HD7
56 ~ ---HD8
55 + --HD9
54 ~-- INO
53 ~~ IN 1
52 ~~ IN2
51 ~-- IN3
50 ~+-- IN4
49 --Q- IN5
48 ~+- IN6
47 ~-- IN7
46 ~--STRB
45 ++-- INIT
44 ~---AB7
43 4--AB6
42 4--AB5
41 ~--AB4
40 ~~AB3
39 ~~AB2
38 ~--AB 1
37 4--ABO
36 ~ - - B U S Y
35 ~--PE
34 ~ - - CNDLP
33 GND
Fig. A-6. E05A03BA (E05A03CA) Pin Diagram
A-7

Lower
Address
CPU
I
I
I
I
IALE ~
I
I
I
AD 13
1
15
Address
Latch
T
Decode
Signal
Address/Data Bus
Ih #
I
I Decoder

t I/
I
I
I
I
I
I
Parallel l/F
Data
Latch
m
WR
CR Motor
Drivek
PF Motor
Driver
Printhead
Driver
Lamp
Driver
Fig. A-7. E05A03BA (E05A03CA) Block Diagram
A-8

REV.-A
A.1.3 2064C CMOS SRAM
The 2064C is a 8K-byte CMOS static RAM. The 2064C has low power consumption, and its input/output
level is compatible with the ITL ICS. Figure A-8 shows the 2064C pin diagram, and Figure A-9 shows
a block diagram for the 2064C static RAM.
q Features
q Capacity of 8192 words X 8 bits
. ITL-compatible 1/0
q Power supply + 5V DC
q 28-pin DIP Switch
q Functions
q AO - Al 2
q w
q -
q Csl, CS2
q DO - D7
q NC
—
AO
At
A2
A3
A4
A5
A6
A7
A8
A9
Input address
Write enable
Output enable
Chip select
Input/Output data
No connection
Memory Ce I I Array
512 X 46 X 6
AtO
All
A12
Csl
ICICSI.CS2
t
6
Cm?ml
CS2 Logic
d--b,,A12
A ?
A 6
A5
A 4
A 3
A 2
-A4
AO
D1
D 2
D 3
Vss
L-
5
~ 2 0 6
7
8
%
10
-
13
14
4 C
25 A8
24 A9
23 All
21 AtO
20 KI
19 D7
17 0 5
16 D4
Fig. A-8. 2064C Pin Diagram
00 D* 02 03 D 4 05 06 07
Fig. A-9. 2064C SRAM Block Diagram
Table A-6. 2064C Truth Table
Csl CS2 m w Ao - A12 DATA 1/0 MODE
H x — — — High impedance Wait
— L — — — High impedance Wait
L H x L Stable Input data Read
L H L H Stable Output data Write
L H H H Stable High impedance Output disable
NOTES: 1. X = HIGH or LOW
2. – = HIGH, LOW or High-impedance
A-9

REV.-A
A.1.4 494 Regulator IC
The 494 regulator IC is described in Figures A-10 and A-1 1 and Table A-7.
( TL9SONLV )
~iEziq OUTPU1
, CONTROL , c0N7R0L
#
c!
El
R,
c1
c1
E2
DEAD
0
I
V
1 I ME + ®CONTROL
Cnnw annl?lcn
v,
NONINVER1lNG
INPUT
INVE~J;tJf
(?EF WT
NONINVE~;;;: GND
1NvERW4;
6 - - - -
FEE08ACR
(1 L495 ONLY)
NON
INV INV I
~— I I II
II
r+:; INV FEED OEAO C T RT GNO Cl
INPUT BACK TIME
INPuT
-
CONTROL
Fig. ‘A”-10. 494 IC Pin and Block Diagrams
Table A-7. 494 IC Port Functions
I pin No. I Signal I Description
Ill NON INV I Non. Inv. Input of error amplifier for output voltage detection.
I 2 I INV I Inv. Input of error amplifier foroutput voltage detection.
3 FEEDBACK Feedback for phase correction.
4 CONTROL Controls transistor OFF time.
5 CT Capacitor for oscillation frequency adjustment.
6 RT Resistor for oscillation frequency adjustment.
7 GND Ground

8 c l Transistor collector for pulse amplification.
9 El Transistor emitter for pulse amplification.
I 10 I E2 I Transistor emitter for pulse amplification.
11 C2 Transistor collector for pulse amplification.
12 Vcc Power
(
13 OUTPUT CONTROL Selection of parallel or push-pull.
14 REF OUT q 1-5V reference voltage
15 INV Inv. Input of error amplifier for output current detection.
16 NON INV Non. Inv. Input of error amplifier for output current detection.
A-1 O

VCC=15V
Vcc
TEST
c
OEAOTIME Cl
I N P U T S
El
t
12K13
- F E E D s A C K
OOUTPUT2
I
}
O(OpEN) ,L495
O(OpEN) o
N L v
50KCl
GND
VOLTAGE
AT Cl
VOLTAGE
A TC2
VOLTAGE
ATCT
DEAD-TIME Tt:REsHoLO VOLr~E --
CONTROL
IN PUT
Ov
I
I THRESHOLO vOLTAGE --
FEEO BACK j
I
07 v I
OUTV
1 1 l_o”/*-
CYCLE M:X
~ MAX
(J J--d
V O L T A G E W A V E F O R M S
Fig. A-1 1.494 Dead Time and Feedback Control
A-1 1

REV.-A
A . 1 . 5 7 4 0 7
The 7407 has hex open-collector buffers as shown in Figure A-12.
Vcc
6A
6Y
5A
5Y
4A
4Y
Fig. A-1 2. 7407 Pin Diagram
/4-1 2

A.2 SCHEMATICS AND DIAGRAMS
—
cl

*

f
Fig. A-1 3. LCPNL Circuit Diagram
A-1 3

‘5 W
‘SW
R70 W
‘7 w
ii’
q 4}
’ 3 4
%2
0s
’ 3 5
R34
cm
’ 3 7
Z03
C17
x
I
SW2
1
Swl
B3S
CNI
.-*
Fig, A-15, ROCX Board Component Layout
A-1 7

REV.-B
Table A-16. Part No. Referenca Table
Ref. No. Description Ref. No. Description
100 LOWER CASE ASSEMBLY 424 RETAINING RING TYPE-E (2.3)
101 BASE PLATE 425 CARRIAGE UNIT
102 RUBBER FOOT 4 2 6 HEAD GROUND PLATE
103 INSULATOR 427 HEAD LOCK LEVER SPRING
104 GROUND PLATE 428 HEAD LOCK LEVER (LEFT)
105 DAMPER 429 HEAD LOCK LEVER (RIGHT)
106 CTB SCREN (M3x8) 430 PAPER END SENSOR
107 CTPS(0) SCREW (M3x6) 431 PAPER GUIDE
108 UPPER CASE 432 PLATEN
109 GEAR WHEEL COVER 433 SHAFT HOLDER
110 PAPER FEED KNOB 434 PLATEN GEAR
111 SHEET GUIDE FRAME 435 LEAF SPRING 8.2 X 0.15 X 15
112 SHEET GUIDE (LEFT) 436 RETAINING RING TYPE-E (6)
113 SHEET GUIDE (RIGHT) 437 CARRIAGE GUIDE SHAFT
114 LOGO PLATE 438 CARRIAGE GUIDE SHAFT LEVER (LE~
115 PRINTER COVER A 439 CARRIAGE GUIDE SHAFT LEVER (RIGHT)
116 PRINTER COVER B 440 CARRIAGE GUIDE SHAH GROUND
117 CTB SCREW (M4x 12) PLATE
118 CBO SCREW (M4x8) 441 CARRIAGE GUIDE
119 CTC SCREW (M3x6) 442 HEAD ADJUSTMENT LEVER
120 CTBS(0) SCREW (M4x8) 443 MOTOR CABLE
121 PAPER GUIDE 444 HEAD CABLE
200 ROCX BOARD UNIT 445 RIBBON MASK
250 LCPNL PANEL 446 PAPER FEED MOTOR
300 ROC FILTER UNIT (120V) 447 PAPER FEED REDUCTION GEAR
301 ROC FILTER UNIT (220V) 448 PRINTHEAD
302 ROC FILTER UNIT (240V) 501 SPROCKET ASSEMBLY (LEFT)
303 ROC FILTER UNIT (120V. 2PLUGS) 502 SPROCKET ASSEMBLY (RIGHT)
304 FUSE ( 125V/1 .25A) 503 PAPER HOLDING COVER (LEFT)
305 FUSE (250V/O.63A) 504 PAPER HOLDING COVER (RIGHT)
400 PRINTER MECHANISM UNIT 505 PAPER HOLDING COVER SPRING
401 RIBBON PIANETARY LEVER ASSEMBLY 506 SPROCKET LOCK LEVER
402 FRAME 507 SHAFT HOLDER
403 PAPER RELEASE LEVER 508 SPROCKET MOUNTING PLATE (LEFT)
404 PAPER GUIDE PLATE 509 SPROCKET MOUNTING PLATE (RIGHT)
405 PAPER GUIDE PLATE RELEASE SHAFT 510 SPROCKET SHAFT
406 PAPER GUIDE PLATE RELEASE LEVER 511 SPROCKET GEAR
407 PAPER FEED ROLLER 512 SPROCKET TRANSMISSION GEAR
408 PAPER FEED ROLLER SHAFT 513 SPROCKET GUIDE SHAFT
409 RIBBON DRIVING GEAR 514 SIDE COVER (LEFT)
410 RIBBON TRANSMISSION GEAR 515 SIDE COVER (RIGHT)
411 RIBBON GEAR 516 PAPER GUIDE ROLLER
412 RIBBON GEARS COVER
413 PAPER FEEDING ROLLER SPRING
414 PAPER GUIDE PIATE SPACER
415 CARRIAGE MOTOR FRAME
416 HOME POSITION SENSOR
417 CARRIAGE MOTOR
418 TIMING BELT
419 BELT PULLEY
420 BELT PULLEY FLANGE
421 BELT PULLEY SHAFT HOLDER
422 BELT TENSION SPRING
423 PLAIN WASHER 3.2 X 0.5 X 7
-,
A-1 8

i EPSON
SEIKO EPSON CORPORATION
BUSINESS INDUSTRIAL INSTRUMENT DIVISION
EPSON OVERSEAS MARKETING LOCATIONS
EPSON AMERICA, INC. EPSON DEUTSCHLAND GmbH
2780 Lomita Blvd., Zulpicher Stra13e 6,4000 Dusseldorf 11
Torrance, Calif. 90505, U.SA. F.R, Germany
Phone: (213) 539-9140 Phone: (021 1) 56030
Telex: 182412 Telex: 8584786
EPSON UK LTD. EPSON FRANCE S. A.
Dorland House. 388 High Road, 55, Rue Deguingand, 92300,
Wemblev, Middlesex, HA9 6UH, U.K. Levallois-Perret, France
Phone: (01) 902-8892 Phone: (1) 4739-6770
Telex: 8814169 Telex: 614202
EPSON AUSTRALIA PTY. LTD. EPSON ELECTRONICS
Unit 3, 17 Rodborough Road, (SINGAPORE) PTEo LTD.
Frenchs Forest, NSW 2086, Australia No. 1 Maritime Square #02-19
Phone: (02) 452-5222 World Trade Centre, Singapore 0409
Telex: 75052 Phone: 2786071/2
Telex: 39536
EPSON ELECTRONICS TRADING LTD. EPSON ELECTRONICS TRADING LTD.
25/F, Harbour Centre, (TAIWAN BRANCH)
25 Harbour Road, Wanchai, 10F, No. 287 Nanking E. Road Sec. 3,
Hong Kong Taipei, Taiwan, R.O.C.
Phone: 5-8314600 Phone: (02) 7160855
Telex: 65542 Telex: 24444
EPSON-SEGI S.P.A. EPSON-STI S.A.
Via Timavo, 12,20124 Milano, Italv Paris, 152,08036 Barcelona, Spain
Phone: 02-6709136 Phone: 410-3400
Telex: 315132 SEGII Telex: 50129 SITK
SEIKO EPSON CORPORATION
(Hirooka Office)
80 Harashinden, Hirooka
Shio]iri-shi, Nagano-ken
399-07 Japan
Phone: (0263) 52-2552
Telex: 3342-214 (SEPSON J)

Epsonlx 800technicalmanual

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