Page 1
r
SERVICE MANUAL
MPS-803
JUNE, 1987 PN-314003-05
_________________:______________
J
z. commodore
COMPUTERS
Page 2
SERVICE MANUAL
MPS-803
JUNE, 1987 PN-314003-05
Commodore Business Machines, Inc.
1200 Wilson Drive, West Chester, Pennsylvania 19380 U.S.A.
Commodore makes no expressed or implied war
ranties w ith regard to the information contained
herein. The information is made available solely on
an as is basis, and the entire risk as to quality and
accuracy is w ith the user. Commodore shall not be
liable for any consequential or incidental damages
in connection with the use of the information con
tained herein. The listing of any available replace
ment part herein does not constitute in any case
a recommendation, warranty or guaranty as to
quality or suitability of such replacement part.
Reproduction or use without expressed permission,
of editorial or pictorial content, in any matter is
prohibited.
This manual contains copyrighted and proprietary information. No part
of this publication may be reproduced, stored in a retrieval system, or
transmitted in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, w ithout the prior written permis
sion of Commodore Electronics Limited.
Copyright 1987 by Commodore Electronics Limited.
All rights reserved.
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MPS-803 SERVICE MANUAL
CONTENTS
CHAPTER 1 SPECIFICATIONS
I. Application ................................................................................................1-1
II. General feature ........................................................................................1-1
III. Structure ..................................................................................................1-1
IV. Basic specifications ................................................................................1-2
V. General specifications ............................................................................1-3
VI. Functional specifications ........................................................................1-4
VII. Interface specifications.............................................................................1-10
CHAPTER 2 OPERATION
I. Precautions ..............................................................................................2-1
II. Parts identification ..................................................................................2-1
III. Operating functions........................................ ......................................2-2
IV. Setting up ................................................................................................2-4
CHAPTER 3 OPERATING PRINCIPLE
I. Operating principle ..................................................................................3-1
II. Operating of the electronic parts.............................................................3-5
CHAPTER 4 MAINTENANCE
I. Notes for the maintenance.......................................................................4-1
II. Disassembly, replacement and adjustment of parts...............................4-1
III. Lubrication.................................................................................................4-16
CHAPTERS CIRCUIT DIAGRAMS ........................................................................................5-1
CHAPTER 6 PACKAGE DRAWINGS ....................................................................................6-1
CHAPTER 7 TROUBLESHOOTING ......................................................................................7-1
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MPS-803 SERVICE MANUAL
CHAPTER 1
SPECIFICATIONS
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MPS-803 SERVICE MANUAL
I. A p p lic a t io n
This Service Manual contains the service information of Brother personal computer printer model
MPS-803.
II. G e n e r a l fe a tu r e
This is a bi-directional printer of dot impact system using 8 vertical dots, capable of printing 60 cps.
III. S tr u c tu r e
PRINTER CONTROL SECTION OPERATION PANEL SECTION
PRINTER
MECHANICAL
SECTION
POWER
SUPPLY
SECTION
This printer is comprised of the printer control, printer mechanical, operation panel and power supply
sections.
1-1
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MPS-803 SERVICE MANUAL
IV . B a s ic s p e c if ic a t io n s
1. Printing method
............
2. Head ..............................
3. Print characters
............
4. Kinds of marks..............
5. Character code ............
6. Standard character size
7. Dot size ........................
8. Print speed....................
9. Printing directions ........
Mark printing..........
10. Max number of columns
11. Character pitch
12. Line pitches
13. Line feed speed
..........
................
..........
14. Paper feed method ...
15. Ink ribbon
....................
16. Print paper
17. Copying capability
Dot matrix impact system
8-pin type
Alphabets in capital and small letters, Arabic
numerals, symbols and graphic elements
Random combination in vertical and horizontal
directions of vertical 7-dot units.
COMMODORE 8-bit code
Vertical 7 dots (2.4mm)
Horizontal 5 dots (2.0mm)
0.3mm (wire diameter)
Horizontal pitch
Vertical pitch
..................................
..............................
1/60 inch
1/72 inch
60 cps
Bi-directional shortest distance printing
Uni-directional shortest distance printing
(righwards)
80 columns
10 cpi
6 or 8 Ipi (on slide switch)
72/7 Ipi .................................... mark printing
4 Ip s ........................character printing (6 Ipi)
5.6 Ip s ...................................... mark printing
Friction feed or Pin feed (optional)
Cassette type fabric ribbon width: 8 mm
length: 10m
color: black
life: approx. 500,000
characters (ANK)
Cut paper
A4 210.8mm (8.3 inches)
letter 216.0mm (8.5 inches)
Paper quality: fine
Regular paper: 45-60 kg/ream
Transfer paper
......................
34kg/ream x 3
(chemical carbon paper)
Continuous paper (option)
101.6mm (4.0 inches)
254mm (10.0 inches)
Paper quality: fine
Regular paper ........................ 45-60kg/ream
Transfer paper
......................
34kg/ream x 3
(point- or line-pasted paper only)
(chemical carbon paper)
original copy + 2 pieces
1-2
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MPS-803 SERVICE MANUAL
18. Detection functions
a. Home Position and Paper Empty switches
HOME POSITION SW:
PAPER EMPTY SW:
19. Operational switching
Paper feed: Except mark print mode, either of 1/6 or 1/8 inch feed shall be selected.
Listener address: Shall be switched to 4 or 5.
20. Operation section
(1) SWITCH PANEL
(1).1 POWER LAMP (red)
a. POWER indication and PE indication.
b. Flickers for PE detection, (at data input)
c. Flickers when MOTOR ERROR.
(1).2 LF SW
a. Has the MANUAL LF function when data is
not input.
b. Has the PE CANCEL function.
c. Has the TEST PRINT START function.
Left end detection
Printing starts of 24th pulse(dot) after this SW
is turned OFF.
Detecting this SW during printing puts the
printer in ERROR mode, and printing stops.
(LINE RELEASE)
Paper empty detection
Turns ON after 3 lines from mechanical
detection.
V . G e n e r a l s p e c if ic a t io n s
1. Power
1.1 Input
AC 100V/117V
AC 220V/240V
1.2 Ouput
+ 5V +5%
+ 24V +4V
2.
Temperature and humidity requirements in operation
..........temperature 5°C - 40°C
humidity 10% - 80%
Wet-bulb: MAX 27°C No dew allowed.
3. Rush-in current ...................................... 20A or less at rated voltage and frequency.
4. Leak current............................................ 1mA or less.
5. Power consumption ................................ 25W or less at test printing at rated voltage
6. Insulation resistance .............................. across AC - FG 500V
± 10% 50Hz.60Hz (+ 2%)
+ 10% 50Hz.60Hz (±2%)
(AC input ± 10%)
(AC input ±10% test print)
and frequency.
50M/t and over
1-3
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MPS-803 SERVICE MANUAL
7. Insulating strength
..................................
across AC - FG
No abnormality shall occur after applying
1000V AC for one minute.
8. External dimensions
..............................
334 (W) x 206 (D) x 94 (H) mm
Refer to the Exterior Drawing
9. Weight 3 kg (approx.)
10. Noise........................................................ 63dB or lower (in rolling ASCII printing)
(when measured by A-SLOW at 1 m away
horizontally from the front face.)
11. Head service life .................................... 20,000,000 characters and over
(ANK printing)
12. Durability MTBF 4,00 hours
..........
excluding head life
Conditions:
Duty for POWER ON time: 20%
Duty for characters: 25%
13. Print quality ............................................ Line feed accuracy 4.23 ± 1.0(1/6 inch feed)
Accumulative line feed accuracy 42.33 ± 1.5
(10 lines, 1/6 inch feed)
Column alignment accuracy 0.4 or less
Accumulative column alignment accuracy
(10 lines) 1.0 or less
Line inclination 1.5 or less
letter paper
(when measured across the first and last
characters) 0.7 or less
fanfold paper
(inclination to the sprocket holes)
VI. Functional specifications (ROM REVISION U32053A)
1. Principal functions
(a) Double-width character output possible by command designation.
(b) Mark printing possible. (BIT IMAGE output)
(c) In mark printing, repetition possible by instruction.
(d) Print start position can be designated by character or dot (POSITIONING).
(e) Standard characters, double-width characters and marks can be mix-printed in one line.
(f) Automatic printing when BUFFER FULL or OVER PRINT possible.
(g) Print function self-checking program equipped.
(h) Reversal printing possible by command designation.
(i) From (") x' 22' to (") or CR code,
X' 00' - X' 1F' and X' 80' - '9F' output the reversal characters of X' - 40' - X' 5F' and
X' CO' - X' DF' respectively.
Note that CR code always executes carriage return.
2. Print modes
(a) STANDARD CHR PRINT mode: bi-directional
(b) DOUBLE-WIDTH CHR PRINT mode: bi-directional
(c) MARK PRINT mode: uni-directional
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MPS-803 SERVICE MANUAL
Reverse print is uni-directional to avoid damaging the print head. For the character font,
either of GRAPHIC (SA = 0) or BUSINESS (SA = 7) mode can be designated by the
secondary address.
3. Interface specifications
COMMODORE serial interface
CON LINE range: from LISTENER ADDRESS reception to UNL reception)
Refer to the INTERFACE SPECIFICATIONS.
4. Function codes
(a) NL (X' OA')
Print command. Executes line feed after printing. Same as LF if used singly. Does not
cancel PRINT mode. Cancels RVS ON.
(b) CR (X' OD')
Print command. Executes line feed after printing. Same as LF if used singly. Does not
cancel PRINT mode. Cancels RVS ON and X' 22' (") function.
(c) BS (X' 08')
Designation command for MARK PRINT mode. Executes MARK PRINT mode after BS
to SI or So. POS and ESC-POS designation right before BS input are invalid. Valid status
codes between BS and SI or SO are BS, POS, ESC-POS, SUB, NL and CR. MARK PRINT
remains designated for the following line if NL or CR is valid. If 8th bit of the MARK data
is "1" or "0", the data works as function code.
(d) SO(OE')
Designation command for DOUBLE-WIDTH CHR PRINT mode. This mode is valid after
SO to SI or BS. POS and ESC-POS designation right before SO input are invalid. Valid
function codes between SO and SI or BS and SO, POS, ESC-PSO, GRAPH, BUSINESS,
RVS ON, RVS OFF, NL and CR. This mode remains designated for the following line
if NL or CR is valid.
(e) SI (OF')
Designation command for STANDARD CHR PRINT mode. Use this print mode right after
turning on the power. This print mode is valid after SI or SO or BS. POS and ESC-POS
designation right before SI input are invalid. Valid function codes between SI and SO
or BS and SI, POS, ESC-POS, GRAPH, BUSINESS, RVS ON, RVS OFF, NL and CR.
This print mode remains designated for the following line if NL or CR is valid.
(f) POS (X' 10') POS"ab" ab is a 2-digit numeric code.
Designation of print start position. Absolute position designation by standard character size.
0 1 2 79
Example
ab^80 is invalid.
If numeric code is not used,
position designation is not
guaranteed.
0
Y S
40 Z
N
L
Print executed at 40th and 41st columns
counted from 0 with standard character size.
2 columns of double-width character
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MPS-803 SERVICE MANUAL
In the example above, if 79 replaces 40, this designation results in OVER PRINT
mode. Automatic line feed is done and printing is done at 0 and 1st columns, and
line feed is done.
Basically, printing data exceeds the printing range, OVER PRINT occurs due to this
designation and automatic line feed is performed. Characters exceed including the
END point are printed at the head of the following line. If this designation is con
tinued, only the last value is valid.
(g) ESC(X'IB') ESC-POS-HP-LP
Designation for print start position. Absolute position designation by dot.
0 1 2 3
4 7 9
HP = X X X
LP
Position
= P8
= 0 0 0 0 0 0 P9 .............
P7 P6
Printing of standard and double-width characters after designating 479 HP.LP 475 is
automatic and done at the head of the following line including line feed. Double-width
characters after designating 479 HP.LP 469 are processed in the same way. If this
designation is continued, only the last value is valid. Only POS can be combined with
ESC, print output except POS is not guaranteed.
(h) SUB (X' 1 A') SUB.n.data (£128)
Repetitive designation command for MARK data. This command is valid in the MARK
PRINT mode, and SUB code (1 BYTE) is ignored in the STANDARD CHR and DOUBLE
WIDTH CHR PRINT mode. 255SniO If 0 is set, it is considered as 256.
Example
X X X P9
P5
P4
l
HP.LP^480 is invalid.
S
P3
P2 P1
............
P1
D
1-6
S B U
I ABC
____
S B
• •
• •
_____________
•
•
! 40 CHRS
0 2 39
A S N
n A I A L
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MPS-803 SERVICE MANUAL
As described in the position designation, standard and double-width characters after
designating (479-239) n (475-239) are printed at the head of the following line including
automatic printing and line feed. Double-width characters after designating (479-239) n
(469-239) are processed in the same way. If data value of this command is smaller than
128, the whole designation is ignored. When data of this command exceeds the printing
range, printing proceeds and starts from the head of the following line including line feed.
(i) GRAPH (X' 91')
GRAPHIC mode designation command.
G) BUSINESS (X '11')
BUSINESS mode designation command.
The above two commands are used to change the character font. This command is cancell
ed by the print command (CR, LF).
(k) RVS ON (X' 12')
REVERSE designation command.
(l) RVS OFF (X' 92')
REVERSE cancel command.
The above two functions are valid in the STANDARD and DOUBLE-WIDTH CHR PRINT
modes. The designation command is cancelled by the print command (CR, LF). The above
(i). 0). (k), (I) are not cancelled by automatic line feed. 0 Undefined codes are ignored.
Those codes except POS, ESC-POS, SUB, NL and CR in the MARK PRINT mode are
ignored.
5. Reversal printing by ASCII (") X' 22'
X' 22' - X' 22' in STANDARD and DOUBLEO-WIDTH CHR PRINT modes or X' 00" - X' 1F'
and X' 80' - X' 9F' between CR codes do not have their function and output the reverse character
of X' 40' - X' 5F' and X' CO - X' DF' respectively.
CR code always performs carriage return. Therefore, reverse of M is not possible by this func
tion. Ordinary character codes follow RVS ON/OFF.
RVS
OFF
RVS
ON
X’ 22 or
X’ 22 X’ 01’ X’ 02 ’ A B X’ 03’ X’ 04’ X’ 0D’
RVS N0N-RVS RVS CANCEL
RVS, (") Function is soley cancelled.
I
X’ 22 X’ 01’ X’ 0 2 ’ A B X’ 03’ X’ 04’ X’ 22’
I_____________________________I I
_____
I I----------------------------------1 (or X’ 0D’)
RVS RVS RVS t
(") Function and RVS ON are cancelled together. Not cancelled by AUTO PRINT LINE FEED.
1-7
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MPS-803 SERVICE MANUAL
6. Secondary address
Secondary address is designated by n3 among OPEN, n1, n2, and n3. Sent to the printer
right after the listener address. Secondary address is often omitted.
(a)
Secondary address = 0
GRAPHIC mode
(b)
Secondary address = 7
BUSINESS mode
(c)
when omitted
GRAPHIC mode
(d)
when other than 0 or 7
Invalid
This function is valid in one ON LINE range, and is switchable by X' 91', X' 11'. If switched
by X' 91', X' 11°, it is cancelled by PRINT COMMAND (CR, LF). The data sent to the
printer is secondary address + X' 60'.
7. Listener address
Listener address is selected to 4 or 5 by the switch on the logic card. The data sent to the
printer is listener address + X' 20'.
8. Paper feed function
Paper feed is executed by LF, CR and line feed after printing length of feed differs with the
mode before. STANDARD, DOUBLE-WIDTH CHR PRINT mode 1/6 inch*
MARK PRINT mode 7/72 inch.
‘ Can select 1/6 or 1/8 by the switch on the logic card. Feed by MANUAL switch is valid in
OFF LINE mode. Feed length follows the print mode right before UNL.
9. Function codes are valid within the ON LINE range and the function setting, set value and
data are held even in the OFF LINE mode.
Note that GRAPH/BUSINESS mode follows the secondary address at OPEN. If the same
secondary address is received when previously set by X' 91', X' 11' and when a print com
mand (CR, LF) is not received, mode setting by X' 91', X' 11' is held. If different secondary
address is received, the mode follows the seconary address.
10. Paper empty detection
OFF LINE: Data is taken in. BUSY status turns on at the start of mechanical operation. At
this time, PE detection works and the POWER LAMP flickers, (at data input)
CLOCK
DATA
FLICKER
1-8
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MPS-803 SERVICE MANUAL
ON LINE: Detection occurs at data input. POWER LAMP flickers. BUSY at the LAST data
is valid.
• PE detection occurs at 3 lines after mechanical detection.
11. COMMODORE Serial Interface
• See Timing and Flow charts.
• See the Specifications for connectors and layout.
12. Automatic printing function
Two types are available.
(1) Print by data buffer full
At the end of printing, the dot position holds the last dot point. This is due to the control
means, and there is no difference between the input data and print output. In this case,
printing is uni-directional in any mode.
(2) When the data exceeds the print range
When the data exceeds the print range, printing is executed to the last column followed
by a line feed. Excess data is printed from the head of the following line.
(Printing not started at the input of 480 columns.)
If data exceeds the margin point, auto line feed is executed and the excess data is printed
on the following line.
Reference: buffer size 152 BYTE
Number of bytes contained
POS: 4 SUB: 4
SI .S O BS . NL . CR RVS .GRAPH/BUSINESS: 1
1 3. Switch panel
(1) LF SW
(a) During OFF LINE, paper feed is executed without regard to the paper. Continuous
LF is executed by pressing it for over 0.5 sec.
(b) If once after the PE detection occurs, load the paper and press this switch to cancel
the PE detection. (Paper feed is not done).
(c) This switch is invalid during ON LINE. Still it has the function to cancel PE until the
first print command and buffer full. Invalid after this until UNL.
(d) Turn the power on while pressing this switch to start automatic printing.
(2) POWER LAMP
(a) Comes on when power is input.
(b) Flickers upon PE detection until it is cancelled. (2.5 times/sec.)
(c) Flickers upon the motor error. (10 times/sec.)
14. Self diagnosis
(a) At POWER ON
If CPU operation is correct, the carriage moves to left (HOME POSITION) and then to
the center to stop.
(b) POWER ON while pressing LF SW
Self printing starts. Performs function check excluding the interface. During self print
ing, manual line feed is invalid. Turn power off to cancel the self diagnosis function.
1-9
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MPS-803 SERVICE MANUAL
VII. Interface specifications
1. Input connector (TCS4460-01-1011: Hoshi Elec. K. K.)
PIN NO.
SIGANL
1
SERIAL SRQ
2 GND
3
SERIAL ATN
4 SERIAL CLK
5 SERIAL DATA
6 RES
2. Electrical requirements
Other requirements: refer to the circuit diagram.
1-10
Page 15
3. INTERFACE CIRCUIT DIAGRAM
ATN
DATA
MPS-803 SERVICE MANUAL
OV
CLOCK
RES
F.B. : FERRITE BEADS
CPU : /*PD7811 (NEC)
1-11
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MPS-803 SERVICE MANUAL
4. Interface functions
a. Listener function directly connected by cable to CBM serial bus. (SRQ and CLK signals
are not controlled by this device.)
b. Listener address can be set to 4 or 5 by switch.
Listener address 4: reception data 24 (hexadecimal)
Listener address 5: reception data 25 (hexadecimal)
c. Secondary, address (SA) can be set to 0 or 7.
SA = 0 (reception data 60) : GRAPHIC mode
SA = 7 (reception data 67) : BUSINESS mode
d. Data input to this device does not finish until the BUSY status inside this device goes off.
e. If this device turns into the ERROR status due to a disorder within this device.
Response to the bus is not executed at all.
4.1 CBM serial interface
a. Data structure
LISTENER ADDRESS (SA) DATA LAST DATA UNL
ATN
a
_________
j t
E01-HANDSHAKE
SYSTEM
LINE-RELEASE
(1) Data is processed by synchronous transfer with CLOCK.
(2) The first bit is the LSB. All the bits are of 8-bit construction.
(3) Listener address data is X' 24 or X' 25. (4 or 5)
(4) SA is X' 60' or X' 67'. X' 60' is used when SA is omitted. (SA is 0, 7)
(5) if address is not identified.
SYSTEM LINE-RELEASE is executed.
DATA
60 — 80 |<s = TPR
SYSTEM LINE-RELEASE
1-12
REFERENCE
CLOCK
A
DATA SAMPLING AT RISING
ik
Page 17
MPS-803 SERVICE MANUAL
5. Program general flow
(This flowchart is not precise. Shows the conception of data flow.)
INITIALIZE ROUTINE DATA RECEPTION & MAIN ROUTINE
DATA RECEPTION ROUTINE
1-13
Page 18
MPS-803 SERVICE MANUAL
LF SW INTERRUPT
DATA PROCESSING ROUTINE
1-14
Page 19
PRINT ROUTINE
MPS-803 SERVICE MANUAL
1-15
Page 20
-803 SERVICE MANUAL
IINESS MODE
01 2 34 5 6 7 8 9 A B C D E F
0
1
2
3
4
5
6
7
8
9
A
B
C
D
-1
E
F
Page 21
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
MPS-803 SERVICE MANUAL
9 A B C D E F
RVS
ON
lllll
GRAPH
■■■■■■
■■■■■■
1-17
Page 22
MPS-803 SERVICE MANUAL
r
i i
v j j =
1-18
Page 23
MPS-803 SERVICE MANUAL
CHAPTER 2
OPERATION
Page 24
MPS-803 SERVICE MANUAL
I. Precautions
1. Wait at least two seconds to turn on the power after it is turned off, otherwise the Printer will
not be initialized properly.
2. Never place the Printer where it is exposed to direct sunlight.
3. Never apply power while you are plugging in or unplugging an input connector.
4. Never turn off the power while the Printer is in motion.
5. Never try to move the print head manually, whether the power is on or off.
6. Do not stop the print head motion while it is printing.
7. Do not print without paper and/or ribbon because the print head might be damaged.
8. Turn off the power quickly and remove a foreign object, if you drop it into the printer.
9. Do not subject the Printer to temperatures below 5°C or above 40°C during operations, or
to a sudden change in temperature.
10. Regarding printing duty:
In graphic mode, using patterns with too much dot density will wear out the print head faster.
We recommend that you use patterns whose dot density is equal to that of ordinary
alphanumerics. The continuing printing of high dot density patterns may adversely affect the
longevity of the print head.
11. Unplug the power cord before trying to take off the outer casing.
12. Do not turn ON/OFF your printer while the system is in operation.
II. Parts identification
Shown below are the names of parts of the printer.
FRONT VIEW
2-1
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MPS-803 SERVICE MANUAL
POWER CORD
III. Operating functions
BACK VIEW
1. Power Switch
2. Paper Release lever
Turns printer ON and OFF
Releases paper in order to adjust paper in right
position.
3. Platen Knob
Once you have properly threaded the paper, you
can use the Paper Feed Knob to move the paper
(both forward and backward directions).
4. Switch Panel
POWER
INDICATOR
a. Paper Advance Switch Use this switch to move paper ahead, 1 line at a
time, in the forward direction only.
And self-printing starts when power is turned on
with this switch depressed.
b. Power Indicator Lights up when printer is turned on.
5. I/O connectors These jacks are used to connect your Printer to the
computer. Use the Serial Interface cable supplied
with Printer. Refer to Section 10 for complete con
nection instructions.
2-2
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MPS-803 SERVICE MANUAL
a-1 The Connector
Pin No.
1
2
3
4
5
6
Signal
SERIAL SRQ
GND
SERIAL ATN
SERIAL CLK
SERIAL DATA
RESET
a-2 The Interface
* Plug the serial interface cable with your Printer into the Serial Bus connector for the
connection. Refer to Section 10 for details on how to connect your Printer to your com
puter.
* When the printer is printing, no data will be transferred from the computer (the data
line is said to be low). When the printer is at rest, data can be transferred from the
computer (the data line is said high).
* When a printer error occurs, all control circuits inside the Printer will stop.
6. Line Feed Select Switch Use this switch to select the line feed.
7. Device Selector Switch
LPI
rrm
6 T
8 : 1/8"
6 : 1/6"
Select the device number 4.
DEVICE
f rnn|
4 5
8. Power Cord Use the power cord supplied with your Printer.
9. Name Plate This plate describes Model Name required power
source voltage, and acquired standards.
10. Connecting the Printer to Your Computer
To connect your printer to your Commodore computer C64, please follow the figures below.
POWER BOX
2-3
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MPS-803 SERVICE MANUAL
Both your computer and printer have two interface connectors.
Please use either of them.
DEVICE
LPI
I m l
1 rani
CJI
6 8
PAPER FEED PITCH
INTERFACE CONNECTOR (both available)
DEVICE NUMBER (use No. 4)
PRINTER REAR PANEL
IV. Setting up
Follow the procedures below to set up the printer.
1. Installing the ribbon cassette.
a. Take out the ribbon cassette from the box. Turn the ribbon advance knob into the direc
tion of arrow to stretch the ribbon.
CLAW
2-4
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MPS-803 SERVICE MANUAL
b. Remove the top cover. Lift both side ends and pull into the direction of arrow.
c. Slip in the ribbon between the carriage and print head. Install the cassette to the printer.
(Note) Make sure the ribbon is not twisted.
2-5
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MPS-803 SERVICE MANUAL
d. Hook the ribbon on the ribbon stopper and pull right the ribbon guide slowly and horizon
tally and fix it to the printer body.
RIBBON GUIDE
RIBBON GUIDE
e. Turn the knob into the direction of arrow to stretch the ribbon.
(Note) Make sure the top end of the ribbon is engaged in the ribbon stopper.
RIBBON ADVANCE KNOB
f. Attach the top cover.
2-6
Page 30
2. Loading the paper
(1) Cut sheet loading
a. Push the paper release lever to OPEN.
b. Insert the paper into the direction of arrow.
MPS-803 SERVICE MANUAL
PAPER LOADING SLIT
c. Pull the paper release lever into the direction of arrow.
PAPER RELEASE LEVER
d. Turn the platen knob as shown until the paper comes out from the window cover.
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MPS-803 SERVICE MANUAL
e. Push the paper release lever to OPEN. Hold the paper and make the edges parallel.
Then follow Section 3.
f. Turn backward the platen knob and set the paper to the print start position.
2. Tractor unit (optional)
a. Remove the top cover. Remove the cover caps by pulling them frontward.
2-8
Page 32
MPS-803 SERVICE MANUAL
b. Insert the front hooks of the tractor unit into the holes located at the upper end of the
top cover and securely fix the unit onto the platen shaft. Engage the rear hooks with the
holes on the back of the printer.
TRACTOR UNIT
FRONT HOOK
REAR HOOK HOLE
c. Insert the fanfold paper into the paper loading slit. Turn the platen knob and feed the paper.
TRACTOR UNIT
2-9
Page 33
MPS-803 SERVICE MANUAL
d. Adjust the sprocket position to fit with paper width. If the sprocket pins do not engage
with the sprocket holes, move the paper holder to fit. Put down the paper holder cover
and push the paper release lever to OPEN.
e. Turn the platen knob and set the paper to the print start position.
(Note 1) After the paper setting, press the paper advance key and feed the paper for
one line.
(Note 2) Always set the paper release lever to OPEN. Set the lever to CLOSE when the
tractor unit is not provided.
3. Performing the Printer Power On Test
You are ready to proceed with the power-on part of the checkout.
(1) Turn on the AC power to your computer and verify that it is working correctly.
(2) To turn on the power to the printer, press the rocker switch at the side of the printer so
that the white dot is visible. In response to the application of AC power, POWER light
in the PAPER ADVANCE switch should be lit and the printer’s microprocessor should
move the print head all the way to the right, then to its home position at the far left. If
this does not happen (and that’s highly unlikely), turn off both machines, check all con
nections and try again. If you still get no response, contact your Commodore dealer.
4. Diagnostic Print Test
Now you can perform the diagnostic print test of the print head and the ribbon cassette as
well after you have inserted the paper. Never allow any printing to occur when there is no
paper in the printer. If the paper empty occurs, the power/error indicator flashes on. Please
install paper and then press the paper advance switch to cancel paper empty status.
To perform the diagnostic print test, simply turn off the printer and then turn on again while
pressing the Paper Advance Switch.
2-10
Page 34
UPS-803 SERVICE MANUAL
CHAPTER 3
OPERATING PRINCIPLE
Page 35
MPS-803 SERVICE MANUAL
Operating principle
1. Printing mechanism
The impact wire dot system is employed. Print head contains 8 solenoids circularly position
ed on the core frame, armature print wires operated by the solenoids and wire guides. The
8 print wires are precision located by the guides on top. Printing is executed when the car
riage travels at the printing speed, the character generator sends the print command pulses
to the driver to operate the solenoids which push the print wire through the armature onto
the ink ribbon finally onto the printing paper. Print timing is controlled by the drive pulse of
the pulse motor which drives the carriage. A standard character is made with 7x5 dot matrix.
The 8 solenoids are selectively activated in each column according to the print data in ROMs.
The print wires return to the original position by spring force after the solenoid operation. Printing
is bi-directional.
3-1
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MPS-803 SERVICE MANUAL
2. Carriage drive mechanism
Revolution of the CR motor is transmitted to the C drive pulley through the motor gear. The
C pulley and the carriage idle pulley are connected with the T-belt MM310-3.2 which is fixed
to the carriage with a holding plate. As the CR motor runs forward and reverse, the C drive
pulley turns to move the T-belt and carriage right and left along the guide bar and frame plate.
By pushing this switch, a projection on the carriage works for the detection.
3-2
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MPS-803 SERVICE MANUAL
3. Paper feed and release mechanism
Paper feed mechanism
Revolution of the LF motor is transmitted to the platen knob gear through the LF idle gear.
Platen is coupled with the platen knob so that it turns as the LF motor does.
PF roller assembly is built right under the platen. Three roller retaining springs are used to
hold three roller assemblies on the platen. Paper is caught between the platen and the roller
and fed as the platen turns.
RELEASE LEVER
RELEASE LEVER
ASSEMBLY
(PAPER FEED CONDITION)
(PAPER RELEASE CONDITION)
3-3
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MPS-803 SERVICE MANUAL
By pressing once the LF key in the OFF LINE status (when the ON LINE lamp is off), the paper
is fed for one line. By keeping on pressing it, the paper is continuously fed.
(a) Paper release mechanism
By setting the release lever to OPEN, the paper release shaft turns through the gear.
The roller retaining spring is released and the platen detaches from the RF roller assy.
(PAPER RELEASE CONDITION). In this condition, paper position can be corrected.
(b) PE switch
PE switch detects the presence of the printing paper. When the paper is being set, the
PE switch actuator is pushed down for printer operation. When the paper has run out,
the PE switch actuator moves away upward to detect the PE condition. Then the ERROR
status turns on and the printer stops.
(PAPER EMPTY) (PAPER IS BEING SET)
4. Ribbon feed mechanism
Revolution of the CR motor is transmitted to the carriage idle pulley through the motor gear,
C drive pulley and T-belt MM310-3.2. And then, to the ribbon drive gear through the idle pulley
shaft secured to the idle pulley and the ribbon idle gear. A spring clutch is mounted on the
idle pulley shaft and the ribbon drive shaft so that the revolution is performed into FORWARD
direction (when the carriage moves from left to right).
When the ribbon cassette assembly is mounted to the mounting part of the body cover, the
ribbon advance gear A of the ribbon cassette assembly engages with the ribbon drive gear.
As the ribbon advance gear A turns, the ribbon advance gear B turns and the ribbon advances.
Ribbon tension is built in the ribbon cassette assembly to provide proper tension to the ribbon.
3-4
Page 39
II. Operation of the electronic parts
1. Structure
MPS-803 SERVICE MANUAL
0 P3, J8, etc. are the connector Nos. on the logic card.
3-5
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MPS-803 SERVICE MANUAL
2. CPU
/iPD7811(NEC) is used for the CPU. Contains a 4K byte ROM and a 256 byte RAM. Pin con
nections are shown below.
PA7-0
PB7-0 Port B
PC7-0 Port C
PD7-0
PF7-0 Port F
nmF
INTI
MODEO
X1, X2
ANT-0
RD
WR
ALE
RESET
VAREF
Port A
Port D
Non Maskable Interrupt
Interrupt Request
Modeo, 1
Crystal
Analog Input
Road Strobe
Write Strobe
Address Latch Enable
Reset
Reference Voltage
The control program and the CG ROM are masked in the 4K byte ROM in the CPU. MODE
1 and MODE 0 terminals are fixed to 'HIGH' and 'LOW' respectively. The analog input ter
minal functions to convert the analog input of OV - + 5V into 8-bit digital data.
*See Section 7 for the addition of PROMs.
3. Interface circuit
3-6
Page 41
MPS-803 SERVICE MANUAL
Connectors J1 and J2 are the DIN connector for interface and each connected in parallel.
DATA LINE is the serial 8-bit data and sampling is done by the CLOCK LINE. ATN LINE
selects data for control (when ATN = 'LOW') and for ordinary data (when ATN = 'HIGH')
RES LINE is used for resetting the printer. Resetting is done in the same way as inputting
the power.
The CPU operates with the synchronous serial input mode made up with the DATA input port
PC1/R x D and the CLOCK input port PC2/3CK. PC3/INT2, INT1 and PC5 are the input port
and PF5 is the output port. INIT signal is a RESET input (RES LINE) from the interface and
connected to the RESET circuit. Faston terminal is connected to the F.G. and shields the in
terface cable. Interface timing is conforming to the CBM Serial Interface. Data reception tim
ing is described in the following.
to E01 HAND SHAKE
___
DATA when ATN = 1
IN THIS CASE,
SA = 0 is valid.
0 After 3.3mm or over from ATN t edge, CLOCK = 1 is detected and DATA is set to 'HIGH',
(at L.A., UNL reception)
1. ATN = 0 is referred to the LISTENER ADDRESS, SECONDARY ADDRESS and UNLISTEN
(UNL).
2. TH is equivalent to BUSY. If requesting NEXT DATA, wait for CLOCK = 1 and set DATA to 1.
In the case of SYSTEM LINE-RELEASE, DATA is set to 60 - 80/ts 'LOW' without regard to
CLOCK. SYSTEM LINE-RELEASE: LISTENER ADDRESS Not identified.
3. TAT = 1ms max. TF = 20 - 1000/iS.
3-7
Page 42
MPS-803 SERVICE MANUAL
----------
r
1
A N T
When Th represents BUSY and the next DATA is requested, DATA = 1 is executed after
CLOCK = 1.
4. Switch panel
3-8
CPU port PCO is an input port. By pressing the PAPER ADVANCE switch, LFSW signal is
set to 'LOW', which executes one line feed. When 'LOW' status is maintained for about 0.5
second, the CONTINUOUS LINE FEED mode turns on. This is maintained until LFSW signal
changes to 'HIGH'. CPU port PC4 is an output port and is normally set to 'HIGH'. This port
is used to flicker the POWER LED. Flickering frequency:
PE detection 2.5 times/sec
MOTOR ERROR 10 times/sec
Page 43
MPS-803 SERVICE MANUAL
5. Limit switch
+5V
HPSW signal turns to 'LOW' at CARRIAGE LEFT END detection. PESW signal is set to
'HIGH' at PE detection. At POWER ON or RESET, the internal ROM is checked. If normal,
the carriage is moved to the left end. If it takes longer than specified to LEFT END detection,
MOTOR ERROR occurs. If LEFT END detection is correctly done, the carriage is moved to
the center. If LEFT END detection still continues, MOTOR ERROR occurs.
Actual PE processing is executed at 3 lines after the PESW signal has turned to 'HIGH' status.
PE detection is executed right before the line feed and print start operations.
6. Function select switches
CPU
Switches SW1 and SW2 can be operated from outside together with the interface connector.
SW1 is used to select the LISTENER ADDRSS (4 or 5). SW2 is used to select the amount
of paper feed (1"/6 or 1"/8). SW1 is set to 4 and SW2, to 6, normally.
3-9
Page 44
MPS-803 SERVICE MANUAL
7. External ROM circuit
CPU is operating by the internal ROM of 4K byte. If necessary, an external ROM 14K byte
can be used for the control. The following paragraphs explain the installation of external ROM.
CPU
6
ov
#3
NC
Vcc
Vpp
PGM
GND
OE
07
06
05
04
03
02
01
00
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
18
DB6
17
DB5
16
DB4
15
DB3
13 DB2
12 DB1
11
DB0
22
19 DB7
JW2
+ 5V
(LS373)
3
2
4
19
5
5
6
16
7 15
8
6
9
9
10 12
r
#2
8Q
7Q
7D
6Q
6D
5Q
5D
4Q
4D
3Q
3D
2Q
2D
1Q
1D
0Q
EG
3
L DB7 62
18
L DB6 61
4
^ DBS 60
17
L DB4 59
14
L DB3 58
7
L DB2 57
8
L DB1 56
13 L DB0 55
11
46
MODE 0
MODE 1
"HD"
Vcc
Vdd
AVcc
V AREF
NMI
PF4
PF3
PF2
PF1
PF0
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
ALE
OV
When the internal ROM is used, Mode 0 terminal is set to 'LOW' and MODE 1 to 'HIGH'.
If the external ROM is to be used, MODE 1 terminal shall be set to 'LOW'.
3-10
Page 45
MPS-803 SERVICE MANUAL
74LS373
-74 LS373 ADDED
JUMP WIRE ADDED
2732
2732 ADDED
i ' \ f \ JW1
\PlOy
/ O
'O O ,
^ —
I JW2
Above three additions enables the external ROM control.
8. Paper feed driver circuit
+ 5V
The LF motor is a step motor of PM type. It is stopped by the detent torque. Operated by
2-2 phase excitation. 1/216 per 1 step with the operating speed at 200 pps. 36 steps is necessary
for 1"/6 feed.
B A
B
A
1 1 0
0
0 1 1
0
0
0
1 1
1
0
0
1
PAPER FEED IS EXECUTED BY THE
EXCITATION SEQUENCE SHOWN ON THE LEFT.
Basically it performs 8-pulse SLEW UP/DOWN Driver IC M54567 often employs the second
source TD62308AP.
3-11
Page 46
MPS-803 SERVICE MANUAL
PIN CONNECTIONS
HEAT SINK
COM 04 14
___
16 15 14 _ 13 12
: _ 11 _ 10 _ 9 _ .
< J—
))
— 1 2 3 -
Vcc 01 11 H
9. Carriage Driver Circuit
CPU
4 -5 - 6 “7” 8 — 1
EAT SINK 12 02 Vcc2
& GND
BASIC CIRCUIT
13 03 COM
3-12
CR motor is a step motor of PM type. When stopping, CRPLS is set to 'HIGH' and is powered
by +9V source for holding. Operated by 2-2 phase excitation. 1 '760 per 1 step with the operating
speed at 360pps. The carriage reverses when the excitation sequence for the LF motor men
tioned before is applied. Basically performs 8-pulse SLEW UP/DOWN. While running CRPLS
is set to 'LOW' and the motor is supplied with + 24V power. Driver IC is same as that for paper
feeding. Pica size takes 1"/10 and is comprised of 6 steps.
Page 47
10. Head Driver Circuit
CPU
MPS-803 SERVICE MANUAL
ov
By setting data by negative logic to CPU ports PBO - PB7 and by setting HPLS signal to
'LOW' for a required period, the head solenoid is driven. At the same time, Vcc terminal of
the driver IC is also controlled. Therefore, the head solenoid transistors on the power source
side and the ground side are always controlled together at the same time. Transistor Q10
on the power source side is provided with a thermo-sensitive resistance (PTH) which has a
positive temperature coefficient. At about 60°C, AN1 signal reaches 2.5(V). While AN1 signal
maintains 2.5V, BUSY is added after printing for about 0.5 second. This is to prevent overheat
of the head.
3-13
Page 48
MPS-803 SERVICE MANUAL
R42
1K
+24V
NOT
PACKAGED.
Since the + 24V power source is not a stable power source, as described later, the head driv
ing time should be properly controlled to stabilize print quality. ANO signal is used for this
purpose, and is the voltage obtained by dividing +24V by resistance.
ui
s
$
o
<
z
o
c/>
CO
—I
0.
+ 24V POWER SOURCE VOLTAGE
ADEQUATE PULSE WIDTH FOR +24V POWER SOURCE VOLTAGE
3-14
Page 49
HEAD DRIVING TIMING CHART
MPS-803 SERVICE MANUAL
APPROX. 2,8 ms
MOTOR PHASE EXCITATION
MOTOR PHASE EXCITATION
HPLS SIGNAL
11. Reset Circuit
+ 24V
--------
TYP.
500 MS
«<
----------
►
(1) Changing period by R20 and C16 at POWER ON.
(2) Period of + 5V power voltage 4.0V at POWER OFF.
(3) Period when INIT signal from interface is 'LOW'.
In the above 3 periods, RESET signal stays 'LOW' and the CPU is initialized. RESET
signal width at POWER ON is about 60ms. Transistors Q6 and Q7 form Schmit property.
3-15
Page 50
MPS-803 SERVICE MANUAL
12. Power Supply Circuit
+ 24V power source is not stable. Voltage at rated input without load is 27 (V) and that at self
printing is 24 (V) approximately. 5V power source is stabilized by the 3-terminal regulator 7805.
Its output is 5 ± 55°/o(V) at normal condition. + 9V power is taken at the regulator input. It has
10 (V) at rated input. The POWER switch has the breaker function. It indicates On though
the breaker is operating. The AC input is turned off at this time. If the breaker has worked,
turn off the switch and then turn it on again to reset. The power transformer is equipped with
a tap. Wires not used shall be pushed into the pocket of the transformer.
3-16
Page 51
MPS-803 SERVICE MANUAL
CHAPTER 4
MAINTENANCE
Page 52
MPS-803 SERVICE MANUAL
I. Notes for the maintenance
The following notes shall be observed during the maintenance operation to prevent disorder which
may be caused by improper handling and operation.
1. Maintenance operation shall be done by the personnel qualified through a regular High-speed
Printer Technical Service Course or who has an equivalent technical qualification.
2. Do not perform printing without loading a printing paper.
3. Do not put things on the printer cover during maintenance and operation.
4. Always turn off the power when replacing the parts and units. Especially, when replacing the
power supply parts, pull off the power cable from the outlet and surely turn off the power.
5. Do not lose screws and washers removed for parts replacement.
6. When using the tools which generate heat such as soldering iron, use care not to damage
the resin parts such as cords and printer cover.
7. When replacing the printed circuit boards, the static electricity may ruin the electronic parts
on the board. To avoid this, operators are required to touch the metal part of the machine
body by hand to discharge the static electricity before handling the boards.
8. Printed circuit boards shall be wrapped in a conductive sheet made of aluminum film when
they are carried.
9. After repairment, check the part repaired and the connectors for looseness and conduct opera
tion check.
II. Disassembly, replacement and adjustment of parts
1. Detachment and attachment of the cover and ribbon cassette
(Detachment).
(1) Lift up part ® . (2 positions right and left) of the TOP COVER and disengage the lock.
Detach it by pulling it forward.
4-1
Page 53
MPS-803 SERVICE MANUAL
(2) Return the HEAD to the HOME POSITION (left end).
(3) Pull up the RIBBON GUIDE with the ribbon being set using right hand.
(4) Turn the RIBBON ADVANCE KNOB into the direction of arrow until the RIBBON GUIDE
stops. Wind up the ribbon completely into the cassette.
RIBBON ADVANCE KNOB
4-2
Page 54
MPS-803 SERVICE MANUAL
(5) Hold the cassette at the center and lift it up to detach from the body.
RIBBON CASSETTE ASSEMBLY
(6) Remove two BODY COVER TIGHTENING SCREWS (+ pan set screw 3x12 DB).
BODY COVER TIGHTENING SCREWS
(+ PAN SET 3 x 12 DB, 2PCS)
4-3
Page 55
Mp$-803
Se* v'<* manual
SWITCH
card
Page 56
MPS-803 SERVICE MANUAL
(Attachment)
(1) Attach the cover following reversely the procedures of detachment.
(2) For attaching the ribbon cassette, refer to Section 4 of CHAPTER 2.
2. Detachment & attachment of the head
(Detachment)
(1) Detach the top cover.
(2) Move the head to the right end as shown below.
PRINT
HEAD
^ --------= ^ =
rl— t*
UP
(J
□
©
(3) Pull out the bent tab using a ball-point pen.
(4) Hold the tab with hand and pull out the cable upward.
4-5
Page 57
MPS-803 SERVICE MANUAL
(5) Slide the HOLDING PLATE fixed on the carriage to the right and pull it upward.
(6) Push the HEAD HOLDING SPRING onto the PLATEN and pull upward the PRINT HEAD
strongly to remove the HEAD.
HEAD HOLDING SPRING
4-6
Page 58
MPS-803 SERVICE MANUAL
(Attachment)
(1) Insert the PRINT HEAD lightly into the CARRIAGE.
(2) Install the CABLE into the CARRIAGE and CABLE BRACKET as shown.
(3) Fit the HOLDING PLATE and slide it to the left to fix.
(4) Push down the HEAD strongly to fix.
(5) Bend the TAB and insert it to the connector.
(6) Make sure the cable is installed in the FRAME GUIDE.
4-7
Page 59
MPS-803 SERVICE MANUAL
(7) Check if the carriage smoothly moves right and left by hand. Then turn on the power and
perform SELF-TEST to check if printing is correctly done. (Turn on the power while pressing
the PAPER ADVANCE switch.)
(Adjustment of the head to platen clearance)
If the clearance is not properly provided, such troubles as uneven darkness of print characters
and ribbon blotting may occur. To avoid this, adjust the clearance properly.
CLEARANCE ADJUSTING
LEVER
(1) Use the CLEARANCE ADJUSTING LEVERS provided to the FRAME on both sides to
adjust the clearance to 0.4 - 0.45mm. Perform adjustment on the both sides of the PLATEN.
4-8
Page 60
MPS-803 SERVICE MANUAL
3. Detachment & attachment of the frame unit
(Detachment)
(1) Detach the cover as described before.
(2) Remove two FRAME TIGHTENING SCREWS (+ pan set 3 x 8 DB).
(3) Pull off the PE/EP HARNESS ASSY and connectors of the CR motor and LF motor. Then
the FRAME UNIT can be separated from the BOTTOM COVER.
Note: Pull off the connectors by holding the connector body. Do not hold the lead wires.
FRAME TIGHTENING SCREWS-
(+PAN SET 3 x 8 DB)
LF MOTOR
ASSEMBLY
CONNECTOR
PE/HP HARNESS
ASSEMBLY CONNECTOR
BOTTOM COVER
CR MOTOR
ASSEMBLY CONNECTOR
(Attachment)
(1) Perform attachment by following reversely the detachment procedures.
Note: Use care not to catch the lead wires during attachment.
4-9
Page 61
MPS-803 SERVICE MANUAL
4. Detachment & attachment of the T-belt
(Detachment)
(1) Detach the FRAME UNIT following the cover and head detachment procedures described
before.
(2) Remove the tightening screw A on the FRAME PLATE. Move the PLATE in the direction
of arrow and remove.
FRAME UNIT
TIGHTENING SCREW A
(3) Turn the PARALLELISM ADJUSTING CAM once located on the right of the FRAME. Pull
it out where the holes coincide, together with the guide bar.
(4) Remove the carriage and T-belt. Attach a new T-belt.
(Attachment)
(1) Perform attachment following reversely the detachment procedures.
(T-belt adjustment)
If tension of the T-belt is not proper, the belt may skip on the gears or the load in carriage
travel often abnormally increases. Adjust T-belt tension when the belt and CR motor are
replaced.
(1) Move the carriage to the left end of the FRAME.
(2) Proper tension is that the T-belt deflects for 8 - 10mm when applied with a vertical load
of 100g at the center of span using a tension gauge. Adjust by loosening the tightening
screw of the CR motor.
4-10
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MPS-803 SERVICE MANUAL
5. Replacement of the CR motor
(Detachment)
(1) Detach the frame unit following the procedures for detaching the cover and head described
before.
(2) Remove two CR MOTOR MOUNTING SCREWS (A) and detach the motor assy from the
FRAME PLATE.
FRAME PLATE CR MOTOR
(3) Remove RETAINING RING E3 (B)from the CR MOTOR UNIT.
(4) Remove FLAT WASHER SMALL 4 (C), CARRIAGE I PULLEY FLANGE (D) and C DRIVE
PULLEY (E) from the shaft.
(5) Attach the parts removed in 4 above to a new CR motor and secure them with RETAIN
ING RING E3 (B).
(Attachment)
(1) Perform attachment following reversely the detachment procedures.
(Adjustment required by replacement of the CR motor)
(1) Adjust the tension of the T-belt. Refer to the adjustment procedures described before.
6. Detachment & attachment of the I pulley unit assy
(Detachment)
(1) Detach the assy following the detachment procedures for the cover, and remove a +
PAN SEMS 3 x 8 DB (A) on the frame front.
4-11
Page 63
MPS-803 SERVICE MANUAL
(Attachment)
(1) Attach a new I PULLEY UNIT following reversely the detachment procedures.
+ PAN SEMS 3 x 8 DB (A)
7. Detachment & attachment for the LF motor
(Detachment)
(1) Detach the FRAME UNIT following reversely the detachment procedures for the cover
and head described before.
(2) Detach the PLATEN ASSY, PLATEN SHAFT BRACKET and RELESE LEVER upward.
Pull outward and disengage the latches of the platen shaft bracket to detach the bracket.
(3) After detaching LF IDLE GEAR (B), remove LF MOTOR TIGHTENING SCREW (C) and
detach LF MOTOR (D) from the frame.
4-12
Page 64
MPS-803 SERVICE MANUAL
(Attachment)
(1) Mount a new LF motor to the frame. Then, attach the LF idle gear, platen assy, release
lever and platen shaft bracket to the frame.
Note:
a. Attach the platen assy, release lever and platen shaft bracket so that the release
lever engages with P release gear on the CLOSE side. See the illustrations below.
CLOSE-
--------------
►OPEN CLOSE-
--------------
►OPEN
X °
b. Make sure that latches (A) of the platen shaft bracket (2 each) surely engage with
the frame.
(Adjustment of LF motor mounting position)
(1) Loosen the LF Motor tightening screw and adjust so that the backlash between LF motor
gear and LF idle gear is maintained within 0.05 to 0.2mm.
8. Detachment and attachment of PE/HP harness assy
(Detachment)
(1) Detach the frame unit following the detachment procedures for the cover and head as
described before.
(2) Turn upside down the frame unit and detach the PE SWITCH HOLDER by opening the
LATCHES (A) into the direction of arrow.
(3 Remove the HP SWITCH MOUNTING SCREW (B) and detach the HP SWITCH upward.
- HP SWITCH MOUNTING SCREW (B)
4-13
Page 65
MPS-803 SERVICE MANUAL
(4) Detach the PE switch assy by opening the latches engaged with the PE switch holder.
(5) Attach a new PE switch assy to the PE switch holder.
Note: Make sure the latches securely engage with the PE switch assy.
(Attachment)
(1) Attach PE switch holder and HP switch following reversely the detachment procedures.
9. Detachment & attachment of the logic card
(Detachment)
(1) Detach the logic card following the detachment procedures of the cover and frame unit
as described before.
(2) Pull out the CONNECTOR (A) of the TRANSFORMER ASSY.
Note: Hold the connector to pull it out. Do not hold the lead wires.
(3) Pull out the INT FG WIRE (B).
(4) Lift up the LOGIC CARD and open the holding parts C, D and E into the direction of ar
row. Disengage and pull out the card forward.
(Attachment)
(1) Attach the card following reversely the detachment procedures.
10. Detachment & attachment of the transformer
(Detachment)
(1) Detach the transformer by following the detachment procedures for the cover and frame
unit.
(2) Disconnect two Faston terminals connected to the noise filter.
(3) Remove two TRANSFORMER MOUNTING SCREWS (A) and slide backward the
transformer to detach.
4-14
Page 66
MPS-803 SERVICE MANUAL
(Attachment)
(1) Attach the TRANSFORMER by inserting it into the hole of the POWER SUPPLY HOLDER
and tighten with two screws.
(2) Connect two Faston terminals to the noise filter.
11. Detachment & attachment of the noise filter
(Detachment)
(1) Detach the noise filter by following the detachment procedures of the cover and frame unit.
(2) Disconnect the Faston terminals (3 left, 2 right) connected to the noise filter.
(3) Remove a mounting screw (B) on top, slide the filter upward to detach.
12. Detachment & attachment of the power switch
(Detachment)
(1) Detach the cover and frame unit as described before.
(2) Pull out upward the POWER SWITCH by opening the latches.
(Attachment)
(1) Attach the switch following reversely the detachment procedure. After attachment, put
the POWER CORD between the rib and switch (to eliminate looseness of the switch
attachment).
4-15
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MPS-803 SERVICE MANUAL
13. Detachment & attachment of the power cord
(Detachment)
(1) Detach the cover and frame unit as described above.
(2) Disconnect two Faston terminals on top from the noise filter, and remove a tightening
screw of the GROUND terminal. Remove two CORD RETAINING SCREWS and pull out
the cord through the hole on the back of the BOTTOM COVER.
(Attachment)
(1) Attach the cord following reversely the detachment procedure.
III. Lubrication
Supply oil to the parts mentioned below at replacement.
(1) GUIDE BAR all around.
(2) Sliding part between FRAME PLATE and CARRIAGE.
(3) Shaft with which LF IDLE GEAR engages.
(4) Engagement between PLATEN SHAFT BRACKET and PLATEN SHAFT.
(5) PE ROLLER SHAFT GUIDE of the FRAME and contacting part between PF ROLLER SHAFT
and ROLLER RETAINING SPRING.
LUBRICATE
(BOTH SIDES)
PF ROLL
LUBRICATE (BOTH SIDES)
ROLLER RETAINING
SPRING
Note: Apply lubricant thinly and evenly. May drip if excessively applied.
4-16
Page 68
MPS-803 SERVICE MANUAL
CHAPTER 5
CIRCUIT DIAGRAMS
Page 69
MPS-803 SERVICE MANUAL
5-1
Page 70
B48W006
MPS-803 SERVICE MANUAL
/ ~ 7~7
> - “ 0 ” -i >— |
l t t J 1
GO
ro
-A
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IO
-
o
r-
r*
<
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(/)
£
o
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to a
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in
<
9d
0 GO
- i r
0 CO
i i !
f !
p
1
I -
t i ! J
1
1
PIN 5
2
2
PIN 7
3
3
PIN 3
4
4
-
5
5 HDRV
6 6
HDRV
7
7
PIN 8
8
8
PIN 1
9
9
PIN 6
10
10
PIN 4
11
11
PIN 2
P4
LFA
6
6
LFB
5 5
LFA
4 4
LFB
3 3
LF DRV
2
2
LF DRV 1
1
P7
J1,J2
:0-
P3
OV
3
3
PESW
2
2
HPSW
1
1
RES
6 6
DATA 5
5
CLOCK
4
4
ATN
3
i
OV 2
2
-
1
1
CR A 6 6
CR A
5 5
CR B
4
4
CR B
3 3
CR DRV
2 2
CR DRV 1
1
5-2
Page 71
MPS-803 SERVICE MANUAL
—
3
ATN
3
5
DATA
c
9
2
OV
2
1
1
4
CLOCK
A
6
RES
C
D
J l
1 M
AC 19V
FASTON (
TERMINAL
HPSW
10V
+ 5V
Q
6 104
OV
(R13)
#3
OE
07
06
05
(2732/64)
04
03
02
01
00
A12
Vcc
A11
A10
Vpp
A9
PGM
A8
A7
A6
A5
A4
A3
CE
A2
A1
GND
AO
4
19
5
5
6 16
7
15
8
6
9
9
10
12
18
^DB6 61
4
CDB5 60
17
^DB4 59
14
^ DB3 58
7
^DB3 57
8
^DB1 56
13 DBO 55
11 46
2. NOT PACKAGED: C26, C27, C29, C31, ZD2
1. OPTION: 2732/64 and 74LS373
OV
-------------
RESET (D7)
2SC 3314
Q7
6
OV
AN1 (F5)
5-3/5-4
Page 72
MPS-803 SERVICE MANUAL
CHAPTER 6
PACKAGE DRAWINGS
Page 73
No.
1
2
3
4
5
6
7
8
9
10
11
MPS-803 SERVICE MANUAL
Parts Code Q’ty Name Commodore Part #
U23051001 1
WINDOW COVER
U23049001 1
TOP COVER ASSY
601020-37
U23082001 2 COVER LID 601020-60
U23047001 1
BODY COVER
601020-35
U23048001 1
FRONT COVER 601020-36
U32143001 1
CIRCUIT BOARD 48W006 ASSY
601020-20 — UL.CSA
571969000 1
CORD HOLDER 2
601020-61
U23057001 2
PAN CUP B 3.0 x 20 601020-62
U23056000 1
POWER SUPPLY HOLDER
601020-63
U23044001 1
BOTTOM COVER ASSY 601020-34
533655001 2
+ PAN SET 3 x 120DB
601020-64
6-1
Page 74
MPS-803 SERVICE MANUAL
2.
No.
Parts Code
Q’ty Name
Commodore Part if
1 U23036001 1
RIBBON CASSETTE ASSY
601020-01
2 U23042001 1 RIBBON GUIDE
6-2
Page 75
MPS-803 SERVICE MANUAL
3.
No.
1
2
3
4
5
6
7
Parts Code
U23002000 1
U23001001 1
U23004000 1 P RELEASE GEAR
U23003001
U22077001
U23005001
U22078001
Q’ty
P HOLDER FILM
FRAME
1 P RELEASE SHAFT
3 PF ROLLER ASSY
2 ROLLER HOLDING SPRING
3
PF ROLLER SHAFT
Name
Commodore Part #
601020-66
601020-67
601020-68
601020-69
601020-70
601020-71
6-3
Page 76
MPS-803 SERVICE MANUAL
m *
4.
No. Parts Code Q’ty
Name
Commodore Part #
1 Z20276001
1
MOTOR ASSY BP483518
601020-03
2 U20545001
2 + PAN SEMS 2.6 x 8DB
601020-76
3 U23028000
1 LF IDLE GEAR 216 601020-14
4
U23032001
1 PLATEN KNOB
601020-16
5 048060345
2
RETAINING RING E6 601020-77
6 U23154000 2 PLATEN SHAFT BRACKET 601020-17
7 U23030001 1 PLATEN
601020-78
8 U23033001
2 PLATEN SHAFT
601020-18
9 U23034001
1
RELEASE LEVER 601020-19
6-4
Page 77
MPS-803 SERVICE MANUAL
MPS-803 SERVICE MANUAL
5.
5.
No.
No.
1
1
2
2
3
3
4
4
5
5
6
6
Parts Code Q’ty
Parts Code Q’ty
U23007000 1
U23007000 1
U23300001 1
U23300001 1
U23017001 1
U23017001 1
U23006000 1
U23006000 1
U23159000 1
U23159000 1
U23008000
U23008000
Name
Name
HOLDER PLATE 601021-20
HOLDER PLATE 601021-20
HEAD ASSY P8
HEAD ASSY P8
T-BELT MM310-3.2
T-BELT MM310-3.2
CARRIAGE 601020-10
CARRIAGE 601020-10
HEAD CABLE SHEAT A 601020-80
HEAD CABLE SHEAT A 601020-80
1 HEAD HOLDING SPRING
1 HEAD HOLDING SPRING
Commodore Part #
Commodore Part #
601020-04
601020-04
601020-05
601020-05
601020-81
601020-81
6-5
6-5
Page 78
MPS-803 SERVICE MANUAL
No.
Parts Code
Q’ty
Name
Commodore Part #
1 U23010000
2
PARALLELISM ADJUSTING CAM
601020-82
2 U23009001
1 GUIDE BAR
601020-12
3
533527001
1
+ PAN SEMS 3 x 8DB
601020-73
4 U23016001 1 FRAME PLATE
601020-83
5 048040345
2
E4 RETAINING RING 601020-84
6 U23022001
1 CARRIAGE IDLE PULLEY
601020-85
7 U23023001
1
CARRIAGE I PULLEY
8 U23019001 1 I PULLEY HOLDER ASSY
601020-87
9 U23026000 1 RIBBON IDLE GEAR
601020-88
10 U23024000 1
PF CLUTCH GEAR
601020-89
11
533527001
1
+ PAN SEMS 3 x 8DB
601020-73
12 U23027001 1
RIBBON DRIVING GEAR
601020-90
13
U04130000
2
CARRIAGE I PULLEY FLANGE
601020-91
14 025040133
1
FLAT WASHER SMALL 4
601020-92
15
048030345
1
RETAINING RING E3
601020-93
16
U23015000
1
C DRIVING PULLEY 601020-94
17
Z20251001 1
42CR MOTOR ASSY
601020-95
18
533527001
2
+ PAN SEMS 3 x 8DB
601020-73
19
U23025001 2
SPRING CLUTH 5
601020-96
20
U510061001
2
WASHER
601020-97
21 025050135
1
FLAT WASHER SMALL 5
601020-98
6-6
Page 79
MPS-803 SERVICE MANUAL
7.
No.
Parts Code
Q’ty Name Commodore Part #
1 U32148001
1 TRANSFORMER 100/117 ASSY
601020-28
U32149001
1 TRANSFORMER 220/240 ASSY
2
519475002
2 COLLAR SCREW 3.5 x 6
601021-01
3 U32150001 1
NOISE FILTER MR2021 601020-29
U32151001 1
NOISE FILTER MR2021V
601020-30
4
U03292001
1
+ - PAN SEMS 3 x 7DA 601021-02
5
U32159001
1
PROTECTOR SW0.5A
601020-31
U32160001 1
PROTECTOR SW0.4A
601020-32
6
U32153001 1
565 AC CORD ASSY #1 601021-26
U32042001 1
565 AC CORD ASSY #2
U32052001 1
565 AC CORD ASSY #3
U32164001 1
565 AC CORD ASSY #4
U32231001
1
565 AC CORD ASSY #5
U32251001
1
565 AC CORD ASSY #6
7
U32242001
1
PE/HP HARNESS WHOLE-ASSY
601020-27
8
037281213 1
PAN TAP 2 TYPES 26 x 12 601021-09
9
U23175000
1
ELECTROSTATIC WIRE 601020-45
6-7
Page 80
MPS-803 SERVICE MANUAL
8.
No.
Parts Code Q’ty
Name
Commodore Part #
1 U32027001 1
CIRCUIT BOARD 8W005 ASSY #0
601020-22
2 U23058000
1
INSULATOR 601021-13
6-8
Page 81
MPS-803 SERVICE MANUAL
9. Optional
No.
Parts Code
Q’ty Name Commodore Part #
1 U23066001
1
W DRIVING GEAR
601020-49
2 048050346
3
RETAINING RING E5
601021-15
3
U23076001
1 PAPER WHEEL 601020-57
4 U23068001
2
BEARING 601020-51
5
U23067001 1
W DRIVE SHAFT
601020-50
6
U23081002 1
PIN FEED COVER L
601020-59
7
037260812 2 PAN TAPPING V SHOE 2.6 601021-16
8 U23064001 1
W IDLE GEAR
601020-48
9 U23063001 1
W IDLE GEAR SHAFT
601021-17
10 U23062002 1
PIN FEED FRAME
601021-18
11 U23080001 1
PIN FEED COVER R
601020-58
12
U23070001
1
WHEEL FRAME L
601020-52
13 U23071001 1 WHEEL DOOR L 601020-53
14 U23074001 1
WHEEL FRAME R
601020-55
15 U23075001
1 WHEEL DOOR R 601020-56
16 U23072001 1
PIN WHEEL
6-9
Page 82
MPS-803 SERVICE MANUAL
CHAPTER 7
TROUBLESHOOTING
Page 83
MPS-803 SERVICE MANUAL
TROUBLESHOOTING
Trouble mode Check
Probable causes
(1) Does not operate by
POWER ON. POWER
LED off)
• Connectors for power fuse
supply
• Fuse
• Power supply voltage
• Incomplete connection from the
power cord to transformer
connector.
• Fuse failure or regulator 805
trouble on the logic card.
(2) Does not operate by
POWER ON. (POWER
LED on)
• POWER LED is flickering.
• +24V power supply
voltage is normal.
• When flickering, MOTOR
ERROR is suspected.
CARRIAGE DRIVER CIRCUIT
or CR MOTOR trouble.
• MOTOR ERROR occurs when
+ 24V is not supplied. Fuse or
rectifier bridge on the logic card
trouble. Power transformer
trouble.
• When not flickering, ROM
CHECK ERROR is suspected.
CPU trouble or RESET signal
circuit trouble.
(3) Head does not move to
center at POWER ON.
• Same as above.
HP switch trouble.
(4) Incorrect printing. • Interface cable is
appropriate.
• May print incorrectly if the
cable is too long.
• CPU on the logic card trouble.
(5) Carriage moves but
does not print.
• Head cable is correctly
connected.
• Head cable is not inserted to
the connector.
• Trouble around transistor Q10.
(6) Specific pins are not
impacted.
• Replace head. • Head trouble.
• CPU and head driver IC
trouble. Correct head resistance
approx. 330. Connector pins
No. 5 and No. 6 are common.
(7) LF Motor becomes
disordered.
• Mechanically heavy-loaded.
• Gears cause racing.
• If mechanical factors are not
suspected, the LF driver IC on
the logic card and CPU trouble.
LF motor resistance:
approx. 1060
GREEN COMMON
(8) CR motor becomes
disordered.
• Mechanically heavy-loaded
such as ribbon load.
• Gears cause racing.
• If mechanical factors are not
suspected, the carriage driver
IC on the logic card and CPU
trouble. Trouble around tran
sistor 08. CR motor resistance:
approx. 1060
RED COMMON
7-1
Page 84
MPS-803 SERVICE MANUAL
TROUBLESHOOTING (Continued)
Trouble mode Check
Probable causes
(9) At POWER ON,
POWER LED does not
come on though
carriage correctly
operates.
• Connector P5 is correctly
connected.
• LED on switch panel trouble.
• Transistors Q1 and Q2 on logic
card trouble.
(10) DEVICE NOT
PRESENT ERROR
occurs.
• LISTENER ADDRESS
setting.
• If setting is correct, SW1
trouble. CPU port trouble.
(11) Amount of line feed
is incorrect.
• Line feed setting. • If setting is correct, SW2
trouble. CPU port trouble.
Page 85
COMPUTERS
Computer Systems Division
1200 Wilson Drive
West Chester, PA 19380
Page 86
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