Epson MX-80 IIIF/T User manual

PRINTER:
EPSONSMX-80 IIIF/T
TECHNICAL SERVICE DATA FOR YOUR PRINTER

SAMS COMPUTERFACTS" EPSON
MODEL MX-80IIIF/T
PRELIMINARY SERVICE CHECKS
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This data provides the user with atime-saving service tool
which is designed for quick isolation and repair of printer
malfunctions.
Check all interconnecting cables for good connection and
correct hook-up before making service checks.
Replacement or repair of the AC Switch Board, Control
Board, Driver Board, Function Board, or connectors may be
necessary after the malfunction has been isolated.
GENERAL OPERATING INSTRUCTIONS
PRINT STATUS (SW1) AND LINE FEED STATUS (SW2)
SW1 On Off
1Compressed Normal
2Not Used
3Paper Out Sensor On Paper Out Sensor Off
4Italic Normal
5Emphasized Normal
6Buzzer On Buzzer Off
7Slashed Zero Regular Zero
8Select Fixed Select Not Fixed
SW2 On Off
1Not Used
2Not Used
3Auto Line Feed with
Carriage Return
Line Feed from Host
4One Inch Skip Over Pert Normal (No Skip)
PRINTER SELF-TEST
To use the built-in self-test function, put paper in the printer and hold down the LF (Line Feed) button while
turning On the printer.
ON LINE, FF AND LF BUTTONS
Printer is On Line (Ready to receive data from the computer) when all three green LED's are On.
The printer is Off Line when only the top green LED is On.
Pressing the On Line button once puts the printer Off Line and pressing it again puts the printer back On
Line.
The printer must be Off Line for the FF (Form Feed) and LF (Line Feed) buttons to function.
CAM/lC Howard W. Sams &Co., Inc.
Mf'lfn#Tii 4300 West 62nd Street, P.O. Box 7092, Indianapolis, Indiana 46206 U.S.A.
The listing of any available replacement part herein does not
constitute in any case arecommendation, warranty or guaranty by
Howard W. Sams &Co., Inc., as to the quality and suitability of such
replacement part. The numbers of these parts have been compiled
from information furnished to Howard W. Sams &Co., Inc., by the
manufacturers of the particular type of replacement part listed.
Reproduction or use, without express permission, of editorial or pictorial
content, in any manner, is prohibited. No patent liability is assumed with
respect to the use of the information contained herein.
©1984 Howard W. Sams &Co., Inc.
4300 West 62nd Street, P.O. Box 7092, Indianapolis, Indiana 46206 U.S.A.
Printed in U.S. of America. 84CF14916 DATE 5-84
COMPUTERFACTS-OFTHEMONTH SET NO. CF2 FOLDER CP1

PRELIMINARY SERVICE CHECKS (Continued)
SERVICE CHECKS
SEE INTERCONNECTING DIAGRAM, PLACEMENT CHART, AND PHOTOS TO MATCH
THE NUMBER IN THE CIRCLES WITH THOSE IN THE FOLLOWING DATA FOR SERVICE
CHECKS TO BE PERFORMED
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PRINTER DEAD
(a) Check Fuse F1. If bad, disconnect the Power
Transformer (T1) connectors CN2 and CN7. Check
for shorted windings or shorts from the windings
to the chassis. Replace Transformer T1 if bad.
(b) If Transformer T1 is good, disconnect connector
CN6 (On Control Board) and check the Regulator
Transistor (Q6) with atransistor tester. If Tran-
sistor Q6 is good, replace or troubleshoot the Con-
trol Board and the Driver Board.
(c) If Fuse F1 is good, apply AC power and check for
120VAC at pins 1and 2of connector CN7. If
120VAC is missing, check the AC Power Cord (P1)
and Master Power Switch (SW10).
(d) If 120VAC is present, disconnect connector CN2
and check the following AC voltages on the secon-
dary windings of Transformer T1 at connector
CN2. 9.83VAC at pins 1to 2, 25.8VAC at pins 3to 4,
10.33VAC at pins 5to 6and 16.63VAC at pins 7 to 8.
If any voltages are missing, replace Transformer
T1. If the voltages are good, replace or
troubleshoot the Control Board and the Driver
Board.
WILL NOT RECEIVE DATA FROM COMPUTER
(a) Check Microcomputer IC (1C) and Interface IC (8B)
by substitution.
PRINT HEAD WILL NOT PRINT
(a) Remove power. Check resistance of the print head
solenoids from pin 7 of connector CN10 to pins 1
thru 5and 9thru 12 of connector CN10 (23 ohms
each). If bad, replace the Print Head (H1). If good,
check the connections and wiring from connector
CN10 to connector CN6 (On Driver Board).
(b) If the connections are good, check the Interface IC ©
(8B) by substitution.
@PRINT HEAD HAS MISSING DOTS
(a) Check the print head solenoid resistance (23
ohms) of the solenoid producing the missing dot
(See Wiring Diagram). If the solenoids check good,
remove the Print Head and check the print head
wires for possible damage.
(b) If the print head is good, check the Microcomputer
IC (1C) and Interface IC (8B) by substitution.
PAPER FEED AND TIMING BELT MOTORS DO NOT
FUNCTION
(a) Check for 26.3V at pin 10 of connector CN6 (On
Driver Board). If 26.3V is missing, remove power
and check the Regulator Transistor (Q6) with a
transistor tester. If Transistor Q6 is good, replace
the Control Board or troubleshoot the power sup-
ply section on the Control Board.
(b) If 26.3V is present, check the Microcomputer IC
(1C) and Slave Microcomputer IC (9B) by substitu-
tion.
(c) If IC's 1C and 9B are good, remove power and
check the resistance of the motor windings (48
ohms each winding). Check the Timing Belt Motor
Assembly C(M1) from pin 13 of connector CN6 (On
Driver Board) to pins 21 thru 24 of connector CN6.
Check the Paper Feed Motor Assembly A(M2) from
pin 14 of connector CN6 to pins 25 thru 28 of con-
nector CN6.
(d) If the motors check good, check the Home Posi-
tion Sensor (PT1) by monitoring pin 20 of connec-
tor CN6 (On Driver Board) with alogic probe while
sliding apiece of paper in and out of the slot in the
Home Position Sensor. The probe should read low
with the paper out of the slot and high with paper
in. If the readings are not correct, check for 2.37V
at pin 12 of connector CN6. If 2.37V is present,
replace the Home Position Sensor (PT1). If 2.37V is
missing, replace or troubleshoot the Driver Board
and the Control Board.
(e) If the Home Position Sensor is good, check the
PTS (Position Timing Sensor) (PT2) by checking for
pulses at pin 19 of connector CN6 while manually
moving the Print Head. If no pulses appear,
replace the PTS Sensor (PT2). If pulses appear,
replace or troubleshoot the Control Board.
FUNCTION BOARD BUTTONS HAVE NO EFFECT
(a) Check connector CN1A for good connection.
(b) Remove power and check contacts of Switches
SW1A, SW2A and SW3 (On Function Board) with
an ohmmeter.
(c) If the IC's are good, replace or troubleshoot the
Control Board and the Driver Board.

PRELIMINARY SERVICE CHECKS (Continued) PRELIMINARY SERVICE CHECKS (Continued)
HOME POSITION SENSOR-
PTS-
CPOSTION TIMING SENSOR)
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GRoundDRIVER board
CN6
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.13
,12
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,7
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PRINTER
MECHANISM
12
11
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9
8
7
6
5
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PRINT HEAD WIRES
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CN7
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MASTER POUER
SW10 T
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120VAC
FUNCTION
BOARD
CN1A
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SW3 SW2A SW1A
POWER
ON
LF FF
INTERCONNECTING DIAGRAM
X
INTERCONNECTING DIAGRAM
COMPUTERFACTS-OF-THE-MONTH SET NO. CF2 FOLDER CP1 |||

PRELIMINARY SERVICE CHECKS (Continued) PRELIMINARY SERVICE CHECKS (Continued)
PARALLEL COMPUTER INTERFACE
5c
GROUND
CN6
28 14
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5a,
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PRINTER MECHANISM
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POWER
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PT1
HOME POSITION
SENSOR
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FUNCTION BOARD
120VAC
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PLACEMENT CHART
IV
PLACEMENT CHART
IX

PRELIMINARY SERVICE CHECKS (Continued)
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CHASSIS-TOP VIEW
COMPUTERFACTSOFTHE-MONTH SET NO. CF2 FOLDER CP1 v

PRELIMINARY SERVICE CHECKS (Continued)
120VAC
CN7
PIN 1
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F1
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AC SWITCH BOARD
VI

PRELIMINARY SERVICE CHECKS (Continued)
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CN5
PIN 1
DRIVER BOARD
VII

PRELIMINARY SERVICE CHECKS (Continued)
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CONTROL BOARD
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PRELIMINARY SERVICE CHECKS (Continued) PRELIMINARY SERVICE CHECKS (Continued)
PARALLEL COMPUTER INTERFACE
5c
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is
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5a,
VR1
PULSE
WIDTH
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PRINTER MECHANISM
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SENSOR
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FUNCTION BOARD
120VAC
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PLACEMENT CHART
IV
PLACEMENT CHART
IX

PRELIMINARY SERVICE CHECKS (Continued) PRELIMINARY SERVICE CHECKS (Continued)
HOME POSITION SENSOR-
PTS-
CPOSTION TIMING SENSOR)
(ie
GRoundDRIVER board
CN6
.14
.13
,12
.11
.10
,9
,8
,7
,6
,5
,4
,3
,2
.1
48 —
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26.3V
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9.83VAC
T1
7.2<
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10.33VAC .2*
A;
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16.63VAC-
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11.4
CN2
CN6
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CONTROL BOARD
©CN10
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PRINTER
MECHANISM
12
11
10
9
8
7
6
5
4
3
2
1
PRINT HEAD WIRES
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CN7
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AC SWITCH BOARD
MASTER POUER
SW10 T
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120VAC
FUNCTION
BOARD
CN1A
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SW3 SW2A SW1A
POWER
ON
LF FF
INTERCONNECTING DIAGRAM
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INTERCONNECTING DIAGRAM
COMPUTERFACTS-OF-THE-MONTH SET NO. CF2 FOLDER CP1 |||

PRELIMINARY SERVICE CHECKS (Continued)
DISASSEMBLY INSTRUCTIONS
CABINET REMOVAL CONTROL BOARD REMOVAL
Remove the knob on the right side. Set the printer on its left
side and remove four Phillips screws from the bottom. Set
the printer back down, lift up on the left side of the cabinet
and move the cabinet to the right to clear the manual paper
feed shaft. Unplug the Function board connector and remove
the cabinet. Remove two Phillips screws from the Function
board and remove the Function board from the cabinet top.
Unplug the ground connector (FG), connector CN2 and con-
nector CN6. Remove one Phillips screw near the center of
the board and two Phillips screws from the transistor heat
sink on the side of the board. Push the three board retaining
clips back, lift up and remove the Control board.
PRINTER MECHANISM REMOVAL
AC SWITCH BOARD REMOVAL
Unplug the power transformer from the board and remove
one Phillips screw holding the board and one Phillips screw
holding the ground lead of the power cord. Remove the AC
Switch board.
Unplug the printer mechanism cable from the Driver board.
Remove two Phillips screws going thru rubber grommets at
the front of the mechanism and remove one Phillips screw
from the grounding strap next to the power transformer.
Slide the mechanism forward and lift mechanism out of the
cabinet bottom.
DRIVER BOARD REMOVAL PAPER END BOARD REMOVAL
Unplug the printer mechanism cable and remove two Phillips Unhook PE Lever Spring (3-2) from Outer Paper Guide (6-1)
screws holding the board. Lift up and remove the Driver and remove Paper End Board.
board. MECHANICAL REMOVAL, REPLACEMENT AND ADJUSTMENTS
RIBBON CARTRIDGE REPLACEMENT TIMING BELT REPLACEMENT
Sfide Carriage Assembly (5-4) to center. Move Scale Shaft
(5-11) back and remove Ribbon Cartridge. Turn knob, on
replacement Ribbon Cartridge, counterclockwise to tighten
ribbon. Install the Ribbon Cartridge with the four tabs (two
on each end) in the slots of Frame Assembly LB and RB (1-1
and 1-2). Press down on Ribbon Cartridge to secure in place.
Slip the ribbon between Print Head (H1) and Ribbon Mask
(5-16). Turn knob to retighten ribbon.
PRINT HEAD REPLACEMENT
Slide Carriage Assembly (5-4) to the right. The Print Head
cable has apull tab. Use this tab to disconnect Print Head
cable from connector on Terminal Board (8-1). Turn Head
Lock Level (5-5) clockwise. Lift and remove the Print Head
(H1). Install replacement by reversing the removal procedure.
TRACTOR FEED REMOVAL
While pressing forward on Sprocket Mounting Levers Land R
(6-18 and 6-20), rock the assembly back and lift from the
printer.
PAPER THICKNESS ADJUSTMENT
Head Adjustment Lever (5-9) moves the Print Head toward
and away from Platen Unit (5-1) to allow for paper thickness.
Maximum paper thickness is 0.3mm (0.012 in). The seven set-
tings provide normal adjustment. If adjustment of lever is re-
quired, because of replacement of parts, perform the follow-
ing procedure.
Set the lever to the center position and loosen the nut secur-
ing Carriage Shaft B(5-8). Insert ascrewdriver into hole in
shaft. Hold screwdriver perpendicular to Base Frame
Assembly B(1-3) and retighten nut. Movement of Head Ad-
justment Lever toward Maximum -position should move
Print Head toward the Platen Unit. If Print Head moves away,
loosen nut, rotate Carriage Shaft B180 degrees and repeat
adjustment.
Remove printer mechanism from the cabinet, see
Disassembly instructions. Loosen Belt Tension Plate
Assembly (4-6) and remove tension from Timing Belt A(4-1).
Remove bottom left and top right screws securing Motor
Heat Sink A(2-2). Remove belt from Belt Driving Pulley
Assembly (4-2). The belt is fitted into the grooved plastic
projection at the base of Carriage Assembly (5-4) and glued
in place. Acutout is provided in Base Frame Assembly B
(1-3) for access to separate the belt from the Carriage
Assembly. Slide the Carriage Assembly over this cutout,
located to the right of the Terminal Board (8-1).
The type of glue used does not produce apermanent bond.
From the bottom, the grooved plastic projection can be
forced apart to remove the belt or, if preferred, adrop of rub-
ber cement solvent (or equivalent) can be used. CAUTION:
Too much solvent can damage the belt. Tension on belt
should not be adjusted until solvent has completely dried.
Install replacement by reversing the removal procedure.
Before adjusting tension apply adrop of glue and allow to
dry to prevent belt from slipping out of the Carriage
Assembly.
TIMING BELT MOTOR REPLACEMENT
Loosen Belt Tension Plate Assembly (4-6) and remove tension
from Timing Belt A(4-1). Remove four mounting screws from
Timing Belt Motor Assembly C(M1). Remove the motor
assembly and Motor Heat Sink A(2-2). Slide the motor
assembly from the heat sink. Observe routing of lead wires
and verify the same routing after performing replacement.
Unsolder motor assembly lead wires from Terminal Board
(8-1). Install replacement by reversing the removal procedure.
PAPER FEEDING MOTOR REPLACEMENT
Remove two mounting screws from Paper Feeding Motor
Assembly A(M2). Observe routing of lead wires and verify the
same routing after performing replacement. Unsolder motor
assembly lead wires from Terminal Board (8-1). Install
replacement by reversing the removal procedure.
2
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PRELIMINARY SERVICE CHECKS (Continued)
TEST EQUIPMENT AND TOOLS
TEST EQUIPMENT
Digital Volt/Ohm Meter
Logic Probe
Transistor Tester
TOOLS
Phillips Screwdriver
Needlenose Pliers
Solvent for Belt
9/32" Socket
Small Screwdriver
PARTS LIST AND DESCRIPTION
ITEM N0. PART NO. DESCRIPTION
F1 X502060020 Fuse (2A @250V)
H1 F401 400000 Print Head
M1 F303027000 Timing Belt Motor Assembly C
M2 F303031000 Paper Feed Motor Assembly A
Q6 Y422306000 Regulator Transistor (2SA1075)
T1 Y422501100 Power Transformer
1C Y422800201 Microcomputer IC
8B X400081550 Interface IC
9B Y422800203 Slave Microcomputer IC
Y422204500 AC Switch Board (MFIL)
Y422205000 Control Board (HMTP)
Y422202000 Driver Board (MDRI)
Y423590000 Printer Mechanism (Model-3310
6a
PIN 1
SW3 CN1A SW2A SW1A
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...,.
FUNCTION BOARD
XII

SAMSCOMPUTERFACTS EPSON
MODEL MX-80IIIF/T
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oMODEL MX-80IIIF/T
PRELIMINARY SERVICE CHECKS
ENCLOSED SAFETY PRECAUTIONS
See page 23.
Page
Adjustments 10
Block Diagram 22
Disassembly Instructions g
Exploded View
Printer Mechanism 8,25
Tractor Feed 24
General Operating Instructions 10
GridTrace Location Guide
Control Board 28
Driver Board 26
Line Definitions 23
Logic Chart 20,21
Mechanical Parts List 9
Mechanical Removal, Replacement
and Adjustment 11
Parts List 14 thru 19
Page
Photos
AC Switch Board 26
Chassis-Top View 28
Control Board 4,5,29
Driver Board 6,7,27
Function Board 21
Safety Precautions 23
Schematics
Control, Driver &AC Switch
Boards 31,32,33
Function, Control &Driver
Boards 2
ICPinouts& Terminal Guides 3,30
Notes 3
Troubleshooting 11,12,13
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©
SAMS Howard W. Sams &Co., Inc.
«)4300 West 62nd Street, P.O. Box 7092, Indianapolis, Indiana 46206 U.S.A.
The listing of any available replacement part herein does not
constitute in any case arecommendation, warranty or guaranty by
Howard W. Sams &Co., Inc., as to the quality and suitability of such
replacement part. The numbers of these parts have been compiled
from information furnished to Howard W. Sams &Co., Inc., by the
manufacturers of the particular type of replacement part listed.
Reproduction or use, without express permission, of editorial or pictorial
content, in any manner, is prohibited. No patent liability is assumed with
respect to the use of the information contained herein.
©1984 Howard W. Sams &Co., Inc.
4300 West 62nd Street, P.O. Box 7092, Indianapolis, Indiana 46206 U.S.A.
Printed in U.S. of America. 84CF14916 DATE 5-84
COMPUTERFACTSOFTHE-MONTH SET NO. CF2 FOLDER CP1

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APHOTOFACT STANDARD NOTATION SCHEMATIC
with rarrmnywa
©Howard W. Sams &Co., Inc. 1984
FUNCTION, CONTROL &DRIVER BOARDS SEE LINE DEFINITIONS ON PAGE 23 FUNCTION, CONTROL &DRIVER BOARDS
-COLUMN
-
132
-COLUMN-
EPSON
MODEL MX-80IIIF/T

IC PINOUTS, TERMINAL GUIDES &SCHEMATIC NOTES
TERMINAL GUIDES
rri ident
HD74LS175P
KJ
,—Ql
CLK
Ql "l
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-| H«3 °3
CLK >
Qo —ii—
i— Do Qo
D2 Q2
CLK
-KP
1A, 2A
QUAD DTYPE FLIP/FLOP
WITH CLEAR
TOP VIEW
TEST0 vcc 40
XTAL 1TEST 1
P27
39
XTAL2 IDACK 38
RESET P26
DRQ 37
SS P25fiBF 36
cs P25/OBF 35
LA P17 34
RD PI6 33
AO PIS 32
WR PI 4 31
SYNC P13 30
DO" P12 29
Dl Pll 28
L)2 P10 27
D3 VI) 1) 26
D4 PROG 25
05 P23 24
D6 m23
i)/ m22
VSS P20 21
SLAVE MICROCOMPUTER
TOP VIEW
ADDRESS
INPUT
A7 VCC 24
A6 AS 23
AS A9 22
A4 Ai! 21
A3 OE 20
a.; A10 19
Al cl 18
A0 07 17
00 06 16
I'll 05 15
02 04 14
GND 03 13
ADDRESS
INPUT
ADDRESS
INPUT
3A, 4A
THREE STATE HEX DRIVER
TOP VIEW
IB
ROM
TOP VIEW
TO VCC 40
XTAL 1Tl a
XTAL 2P27 38
RESET P26 37
SS P25 36
INT P24 35
FA it; 34
1!.": P16 33
PSEN P15 32
*R P14 31
ALE PI 330
DBO P12 29
lb: Pll 28
DB2 P10 27
DBS VDD 26
DB4 PROG 25
DBS P23 24
186 P22 23
DB7 P21 22
VSS P20 21
IC
MICROCOMPUTER
TOP VIEW
INTERFACE
TOP VIEW
BCE
Q2
FRONT VIEW
Q3 THRU Q5
BOTTOM VIEW
p^
I1
1
BE C
Q6
FRONT VIEW
1PC3 VCC 40
2PC4 PC2 39 '
3TIMER
IN
PCI 38
4RESET PC0 37 .
5PC5 pb; 36
6TIMER
OUT PB6 35
710/M PBS 34
8CE
ORCE P84 33
9RD PB3 32
10 WR PB7 31
11 ALE FBI 30
12 AD0 PB0 29
13 AD1 PA7 28
14 AD2 PA6 27
15 AD3 PA5 26
16 AD4 PA4 25
17 AD5 PA3 24
18 A06 PA2 23
19 AD/ PA1 22
20 VSS PA0 21
E>
L>
L>
L>
[>
F>
L>
O
cnTa
wiring view
171
n
n
n
n
niU
nu
i31
1
Is 4Lj
CN2
WIRING VIEW
CN6
WIRING VIEW
2C, 2E, 3C, 3E,
6D, 6E, 7C, 70, 7E
TOP VIEW
5E, 6B, 7B
TOP VIEW
I I I IIIIIIII
23 4 5612 3 4 5 6 78910 11
RM1 RM2 RM3. RM4
FRONT VIEW FRONT VIEW
DRIVE BOARD ONLY
IDENT
IA
TOP VIEW
DRIVE BOARD ONLY
Ql THRU Q20
FRONT VIEW
DRIVE BOARD ONLY
IDENT
IIIIIII
17 3 4 5 6 7
RM5
FRONT VIEW
DRIVE BOARD ONLY
IDENT
DRIVE BOARD ONLY
14 13 17 11 10 9 8 76 5 43 2
15 16 17 18 19 20 71 72 324 25 26 27 28
CN6
WIRING VIEW
IIIIIII I III
1I 3 456789 10 11
RM1
FRONT VIEW
;17 16 15 14 13 12 11 10 9 7 6543 2 1
aaw~w-1
ai b aaa«a
—
i
"ii"a a
36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
CN1
WIRING VIEW
IIIIIIIII
12 345678 9
RM2
FRONT VIEW
2345 6 78 9 10 11 12
jiibii !! ii j|l 1aIaIb-|
•o2
•.ft
ao8
•*10
11 ••12
13 ••14
15 •«16
17 ••u
19 ••20
21 • • 22
CN10
SOCKET VIEW
CN4, CN5
PIN VIEW
CN3
SOCKET VIEW
HI
PRINT HEAD
FRONT VIEW
SCHEMATIC NOTES
-a— Circuitry not used in some versions
—Circuitry used in some versions
eSee parts list
+Ground
^Common tie point
Voltages measured with digital meter.
Waveforms and voltages are taken from ground, unless noted
otherwise.
Voltages, waveforms and logic readings taken with printer On
Line and not printing unless noted. Printer Self-Test mode
used to get readings taken while printing.
Switches SW1 and SW2 set as shown on schematic.
Waveforms taken with triggered scope and Sweep/Time
switch in Calibrate position, scope input set for DC coupl-
ing on "0" reference voltage waveforms. Switch to AC in-
put to view waveforms after DC reference is measured
when necessary. Each waveform is 7.5cm width with DC
reference voltage given at the bottom line of each wave-
form. Time in /is per cm, given with p-p reading at the end
of each waveform.
Item numbers in rectangles appear in the alignment/adjust-
ment instructions.
Supply voltage maintained as shown at input.
Controls adjusted for normal operation.
Terminal identification may not be found on unit.
Resistors are V2VJ or less, 10% unless noted.
Value in ()used in some versions.
NOTE: Logic probe readings taken with printer On Line and
not printing unless otherwise noted. Printer Self-Test
mode used to get readings with switches SW1 and
SW2 set as shown on schematic.
Logic Probe Display
L=Low
H=High
P=Pulse
*=Open (No lights On)
(1) Probe indicates Pwhen printer is printing.
(2) Probe indicates Lwith no paper in printer.
(3) Probe indicates Hwith no paper in printer.
(4) Probe indicates Lwhen print head is not at home posi-
tion.
(5) Probe indicates Hwhen print head is not at home posi-
tion.
(6) Probe indicates Hwhen print head moves from left to
right, and Lwhen head moves from right to left.
(7) Probe indicates Hwhen the printer is not on line.
(8) Probe indicates Lwhen the printer is not on line.
(9) Probe indicates Pwhen the printer is not on line or is
printing.
(10) Probe indicates Lwhen printer is printing.
(11) Probe indicates Pwhen aline feed occurs.
(12) Probe indicates Lwhen aline feed occurs.
(13) Probe indicates Hwhen printing.
(14) Probe indicates Hwhen aline feed occurs.
(15) Probe indicates Lwhen buzzer sounds.
(16) Probe indicates Hwhen buzzer sounds.
(17) Probe indicates Hwhen printing in compressed mode.
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30 COMPUTERFACTS-OF-THE-MONTH SET NO. CF2 FOLDER CP1

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CONTROL BOARD
COMPUTERFACTS-OF-THE-MONTH SET NO. CF2 FOLDER CP1 5

DRIVER BOARD
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DRIVER BOARD
COMPUTERFAGTS-QF-THE-MONTH SET NO. CF2 FOLDER CP1 7