iSi 487 User manual

ISi MODEL 487
TECHMICAL MANUAL

487 Technical Manual
Revision Date:
November 2, 1984

Table of Contents
Chapter 1 G:EllERAL INFORMATION
1.1 SCOPE OF THIS MANUAL
1.2 G:EllERAL DESCRIPTION
1.3 PHYSICAL DESCRIPTION
1.3 .1 PRINTING MECHANISM
1.3.2 PAPER HANDLING MECHANISM
1.3.3 ELECTRONICS
1.3.4 POWER SUPPLY
1.4 PRINTER OPERATION
1.4.1 CHARACTER PRINTING
1.4.2 PAPER K>TION
1.4.3 SPECIAL FUNCTIONS
1.5 RELATED PUBLICATIONS
1.5.1 UNPACKING/REPACKING INSTRUCTIONS
1.5.2 OPERATOR'S GUIDE - ISI M'.>DEL 487
1.6 COMPATIBILITY
1.7 PRINTING SPECIFICATIONS
1.8 PAPER HANDLING
1.9 PAPER REQUIREMENTS
1.10 PHYSICAL/ENVIRONMENTAL SPECIFICATIONS
2
2
2
3
5
5
5
5
5
5
7
7
7
7
8
8
8
9
9
10
Chapter 2 THEORY OF OPERATION 11
2.1 G:EllERAL 11
2.2 BASIC PRINTER OPERATION 11
2.3 C-BUS DATA INTERFACE CABLE 16
2.4 PRINT CONTROLLER 19
2. 4•1 DAT A ARGUMENTS DEFINITION 19
2.4.2 STATUS BYTES 19
2.4.3 PAPER K>TION ARGUMENT DESCRIPTION 20
2.4.4 PRINTER STATUS BYTE (ADDRESS 0016, BIT 0 = LSB) 21
2.4.5 SELF-TEST STATUS BYTE (ADDRESS OE16) 22
2.4.6 ACCUMULATED PAPEB K>TION STEPS (ADDRESS 0116 AND
0216) 23
2.4.7 PAPER K>TION STEPS REMAINING AFTER .ABORT (ADDRESS
0316 AND 0416) 24
2.4.8 REVERSE PAPER K>TION BEFORE PRINT (ADDRESS 0516 AND
0616) 24
i

2.4.9 FORWARD PAPER K>TION BEFORE PRINT (ADDRESS 0716 AND
0816) 24
2.4.10 PRINT COMMAND (ADDRESS 0916 BIT 0 = LSB) 24
2.4.11 REVERSE PAPER K:lTION AFTER PRINT (ADDRESS OA16 AND
OB16) 25
2.4.12 FORWARD PAPER K:lTION AFTER PRINT (ADDRESS OC 16 AND
OD16) 25
2.4.13 PRINT DENSITY/TYPE (ADDRESS OF16) 25
2.4.14 MATRIX SIZE (ADDRESS 1F16) 26
2.4.15 DOT PITCH ADDRESS (ADDRESS 1E16) 26
2.4.16 INTER-CHARACTER SKIP (ADDRESS 1D16) 26
2.5 POSITIONAL INFORMATION AND USE 27
2.5 .1 STANDARD CHARACTER PLACEMENT 27
2.5.2 GRAPHIC K>DE 27
2.6 CHARACTER PATTERN GENERATION 27
2.6.1 GRAPHIC K>DE 28
2. 7 STEPPER DRIVER 28
2.8 CARRIAGE SERVO SYSTEM 29
2.9 RIBBON K>TOR DRIVER 32
2.10 HEAD DRIVER CIRCUIT 32
Chapter 3 MAINTENANCE 33
3.1 MAINTENANCE SHfiARY 33
3.2 PRINTER HARKING AND CONFIGURATION 33
3.2.1 PRINTER NAMEPLATE 33
3.2 .2 PRINTER CIRCUIT BOARD MARKING 34
3.2.3 PRINTER CONFIGURATION 35
3.2.4 LANGUAGE SELECT SWITCH SETTINGS 36
3.2.5 IBM K>DEL SELECT SWITCHES 37
3.2.6 SPECIAL FUNCTION SWITCH SETTINGS 38
3.3 ISI 487 ERROR CODES 38
3.4 RONNING A SELF-TEST 39
3.4.1 RAM TEST 40
3.4.2 ERRORS 00 POWER UP 41
3.5 PREVENTIVE MAINTENANCE 41
3.6 TROUBLESHOOTING GUIDE 42
3. 7 TESTING THE IS! INTERFACE PCB 43
Chapter 4 ADJUSTMENTS 45
4 .1 ADJUSTMENT SJtffARY 45
4.2 CARRIAGE DRIVE 45
4.3 CARRIAGE DRIVE BELT 46
ii

4.4 PAPER DRIVE BELT
4.5 TRACTOR GEAR BACKLASH
4.6 PAPER EMPTY SWITCH
4. 7 OPTIC SENSOR AND ENCODER/TIMING DISC
4. 7 .1 MECHANICAL ADJUSTMENT
4.7.2 ELECTRICAL ADJUSTMENT
4.8 HORIZONTAL OFFSET ADJUSTMENT
Chapter 5 REMOVAL/REPLACEMENT
5.1 REMOVAL/REPLACEMENT, RECOMMENDED SPARES
5.2 PAPER RACK cnn.ET ASSEMBLY
5.3 PAPER RACK INLET
5.4 COVER ASSEMBLIES
5 .4 .1 TOP COVER
5.4.2 REAR COVER
5 .4 .3 BODY COVER
5. 5 COVER INTERLOCK MAG NET
5.6 RIBBON CASSETTE AND GUIDE
5.7 PRINT HEAD ASSEMBLY
5 •8 HEAD FL EX CABLE
5.9 HEAD ADAPTER PCB
5 .10 PRINTER MECHANISM
5.10.1 REMOVAL/REPLACEMENT OF PRINTER MECHANISM
5.10.2 PLACING PRINT MECHANISM IN TILT POSITION
5 .11 DUST COVER
5.12 CARRIAGE DRIVE K>TOR BELT
5.13 CARRIAGE DRIVE BELT
5 • 14 CARRIAGE DRIVE K>TOR AND RIBBON DRIVE K>TOR K>UNTING
BRACKET
5.15 OPTIC SENSOR ASSEMBLY
5. 16 CARRIAGE DRIVE K>TOR
5 .17 m;coDER/TIMING DISC
5. 18 RIBBON DRIVE K>TOR
5.19 COVER INTERLOCK SWITCH
5 .20 PAPER DRIVE BELT
5 .21 PAPER DRIVE K>TOR
5.22 TRACTOR ASSEMBLIES, LEFT/RIGHT
5.23 PAPER EMPTY SWITCH
5.24 POWER SUPPLY ASSEMBLY
5.25 PRINT CONTROLLER PCB
5.26 FORMAT CONTROLLER PCB (ISI INTERFACE PCB)
5.27 PICO FiJSE
5 .28 Cit/OFF SWITCH
5.29 MAIN FUSE
5.30 POWER CORD
5.31 COVER LATCH SPRINGS
iii
46
48
49
50
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51
53
57
57
58
58
59
59
59
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61
61
62
63
64
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71
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81
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84
84
85
87
89
89
90

5.32 CONVERTING 'mE POWER SJPPLY 'l'O 220V
5.33 RECOMMENDED SPARE PARTS LISTING
Chapter 6 ILLUSTRATED PARTS BREAKDOWN
6 .1 INTRODUCTION
6.1.1 ITEM
6 .1 .2 PART NUMBER
6.1.3 DFSCRIPTION
6. 1 .4 QUANTITY
Chapter 7 ELECTRICAL DRAWINGS
Chapter 8 PICO POSE COLOR CODE
8.1 GENERAL INFORMATION
iv
91
93
95
95
95
95
95
95
127
128
12H

FEDERAL COMMUNICATIONS COMMISSION
RADIO FREX2UENCY INTERFERENCE
STATEMENT
This unit has been type tested and found to comply
with the limits for a Class A computing device in
accordance with the specifications for Subpart J of
Part 15 of FCC rules, which are designed to provide
reasonable protection against such interference in
a commercial installation.
- 1 -

Chapter 1
GENERAL IHFORMATION
1. 1 SCOPE OF THIS MANUAL
This technical manual provides detailed information on the theory of
operation, maintenance, adjustment and recommended spare parts replacement
for the ISI Model 487. The manual is for use by qualified service personnel
who maintain electronic and electro-mechanical equipment.
ISI offers contract maintenance service nationwide for your ISI 487.
Service for printers not on contract may also be offered in your area. For
details on these services, call [phone].
1.2 GlmERAL DF.SCRIPTION
The ISI Model 487 is a high speed, bidirectional, impact printer that
uses dot matrix techniques for character generation. The printer is
completely self-contained, composed of mechanical, electro-mechanical
components and printed circuit boards. The printed circuit boards use
microprocessor technology to minimize components and increase reliability.
Maximum throughput is achieved with bidirectional printing which seeks
the shortest path to the next line of characters when printing successive
lines of data. Paper is moved through the printer by means of a stepper
motor.
The ISI Model 487 contains many features to help perform the printing job
more easily and efficiently. Some of the more significant features are:
-200 CPS Smart, Bidirectional Printing
- Direct compatibility with IBM 3270 systems
Switch Selectable Forms Length
Switch Selectable Characters Per Inch
- 2 -

-Switch Selectable Lines Per Inch
- Fanfold Forms or Cut Sheet Forms Handling
- Demand Document Feature
Self-Test Capability
Figure 1-1. MODEL 487 PRINTER
The printer is lightweight,
compatible with IBM 3274/3276
support.
easy to install, operate and maintain; and
systems. The ISI 487 offers full SDLC/SCS
1.3 PHYSICAL DE,SCRIPTION
The ISI 487 is compact and lightweight. The printer measures 22 inches
wide, 18 inches deep and 8 inches high. The printer weighs 40 lbs.
The printer covers include several plastic covers; the top cover, body
cover, rear cover, and base cover. The body cover has an opening in the
lower right corner for the control panel.
There are six major assemblies within the printer:
mechanism, paper handling mechanism, printer electronics,
interface, and control panel.
- 3 -
the printing
power supply,

Pigure 1-2. MAJOR ASSEMBLIES MODEL 487
- .II -

1•3•1 PRINTING MECH AN ISM
The printing mechanism consists of the print head assembly, carriage
assembly and carriage drive components. The carriage drive components are
the DC drive motor, drive belts, pulleys, encoder/timing disc and optical
sensor. These components drive the carriage and attached print head back
and forth along the platen.
1.3.2 PAPER HANDLING MECHANISM
The paper handling mechanism is capable of handling either fanfold forms
or cut sheet forms. The mechanism consists of a stepper motor, pin feed
tractors, paper guides and drive rollers. The mechanism handles up to six
part forms.
1.3.3 ELECTRONICS
The printer electronics consist of three printed circuit boards (pcb);
the Print Controller pcb, the Format Controller pcb, and the Control Panel
pcb, attached to the top cover by velcro strips.
The Format Controller pcb contains the input connectors.
called the ISI Interface pcb.
1.3.4 POWER SUPPLY
It is also
The power supply is located in the left front of the printer and is
completely enclosed. The power supply, an "off-line" switching type, is
used as the primary power source, supplying +5, +12, -12 and +35 Vdc.
1.4 PRINTER OPERATION
Basically, all printer functions
categories: 1.) character printing,
functions.
1.4.1 CHARACTER PRINTING
can be grouped into one of the three
2.) paper motion, and 3.) special
Once the data has been received and formatted by the Format Controller
(ISI Interface), characters are printed by selectively activat1ng the eight
print wires aligned vertically in the print head. A nintn wire in tne
print head, under microprocessor control, provides the underlining
capability in the printer. The print commands to activate tne print wires
- 5 -

are developed by the Print Controller pcb PROMs.
0 0
Figure 1-3. CHARACTER PRINTING/PAPER MOTIOO
As the print head moves across the paper, the appropriate print wires are
momentarily activated driving them against the ribbon, paper and platen to
torm the dot matrix character.
As shown in Figure 1-3, the print head is attached to the carriage
assembly, which in turn is attached to a carriage drive belt. The carriage
is driven in the forward or reverse direction by the carriage drive motor
which rotates the belt clockwise (forward direction) or counterclockwise
(reverse direction).
- 6 -

1.4.2 PAPER K>TION
Paper is moved by pressing the paper motion switches; INDEX to line feed, f
for paper forward, .. for paper reverse, or FORM FEED. The information
provided by the Format Controller pcb to the Print Controller pcb
establishes the direction and the amount of paper motion. Pressing .. , or~
with paper positioned will cause top-of-form to change, not the index.
Physically, paper is moved by the torque from the paper stepper motor
which is applied to the print feed tractor drive gears which move the paper
up or down as shown in Figure 1-3.
1.4.3 SPECIAL FUNCTIONS
As a standard feature, the ISI 487 supports a variety of language sets.
These language sets are accessed by dip switch pack E60 located inside of
the rear of the printer housing. See Section 3.2.4 for settings.
Also as a standard feature, the ISI 487 may be set to emulate various IBM
buffer sizes. IBM Models 2-5 are supported by the selection of dip switch
pack E60. See Section 3.2.5 for the corresponding settings.
The ISI 487 printer has a self-test procedure which is activated by
pressing TF.sT on the operator control panel when the printer is in 2ND
FUNCTION. See Section 3.4 for complete instruction on running a self-test
and using the test to diagnose your printer.
Special printing functions such as print form feed on local copy, are
also available on the ISI 487. These printing functions accessed by dip
switch pack E81, located through the rear of the printer housing. See
Section 3.2.6 for complete details.
1.5 RELATED PUBLICATIONS
The following publications document the ISI Model 487 printer. These
publications are available through Interface Systems, Inc. at 5855
Interface Drive, Ann Arbor, MI 48103, Tel(MI): [phone], Tel(out of
state) 1-800-544-4072, or TWX 810-223-6058.
1.5.1 UNPACKING/REPACKING INSTRUCTIONS
The unpacking/repacking instructions are attached to the outside of the
shipping container and provide the necessary information to unpack or
repack the printer.
- 7 -

1.5.2 OPERATOR'S GUIDE - ISI K>DEL 487
The Operator's Guide provides a general description of the printer and
information necessary to install, program, operate, and maintain the
printer on a users level. This information includes set-up procedures,
operating instructions and programming instructions.
1.6 COMPATIBILITY
The 487 is available as either a Type A (3287 feature 8331). The 487 Type
A printer is SNA compatible and processes SCS commands as a standard
feature. Specified controller and system compatibility is outlined in the
table below.
SYSTEM/CONTROLLER TYPE
IBM 3081
IBM 3274
IBM 3276
IBM 3791
IBM 4331
IBM 4341
Memorex 2076
Telex 276
MDS/Trivex 8074 CA Adapter)
1.7 PRINTING SPECIFICATIONS
487 PRINTER TYPE
A
A
A
B
A
A
A
A
A
Printing Method •••••••••••••••••••••••• Impact, dot matrix, bidirectional,
logic seeking
Dot Matrix •••••••••••••••••••••••••••• 7 dots wide by 8 dots high; 9th wire
underline
Print Speed ••••••••••••••••••••••••••• 200 characters per second
Country Character Sets •••••••••••••••• English, U.S., Austrian/German, Aus-
trian/German Alt., Danish/Norwegian,
- 8 -

,
Printing Method •••••••••••••••••••••••• Impact, dot matrix, bidirectional,
logic seeking
Dot Matrix •••••••••••••••••••••••••••• 7 dots wide by 8 dots high; 9th wire
underline
Print Speed ••••••••••••••••••••••••••• 200 characters per second
Country Character Sets •••••••••••••••• English, U.S., Austrian/German, Aus-
trian/German Alt., Danish/Norwegian,
Danish/Norwegian Alt., Finnish/Swe-
dish, Finnish/Swedish Alt., French,
Italian, Portugese Alt., Spanish,
English, U.K., Belgian, Internation-
al, Japanese/English, Canadian/French,
Brazilian, Canadian Bi-lingual.
Horizontal Pitch •••••••••••••••••••••• Programmable for 10, and
16.67 characters per inch
Maximum Line Length ••••••••••••••••••• 10 cpi -132 columns
,6.67 cpi -220 columns
1.8 PAPER HANDLING
Vertical Pitch •••••••••••••••••••••••• 6 or 8 lines per inch, switch
selectable
Vertical Slew Speed ••••••••••••••••••• 8 inches per second
Forms Length •••••••••••••••••••••••••• 1 to 103 lines
Paper Movement •••••••••••••••••••••••• Bidirectional
1.9 PAPER REX}UIREMENTS
Fanfold Forms
Width
Copies ........ ~ .............. .
- 9 -
3.0 to 15.0 inches (76 to 381 mm)
Up to six parts

1.10 PHYSICAL/ENVIRONMENTAL SPECIFICATIQNS
Height •••••••••••••••••••••••••••••••• 7.5 inches (190.5 mm)
Depth ................................. 18.25
inches (463.5 mm)
Width .................................
22.5 inches (571.5 mm)
Weight •••••••••••••••••••••••••••••••• 40 lbs. (18.1 kg)
Temperature ••••••••••••••••••••••••••• Operating: 50 to 104 F
( 10 to 40 C)
Storage: -40 to 151 F
(-40 to 66 C)
Humidity •••••••••••••••••••••••••••••• Operating: 10% to 90%
(no condensation)
Storage: 10% to 95%
(no condensation)
Power
Switcher Power Supply ••••••••• 98 VAC to 125 VAC or 195 VAC to 24b
VAC - 47 to 63 Hz
Input Current ••••••••••••••••• 4A max. to 110 VAC
2A mac. to 220 VAC
- 10 -

Chapter 2
THEORY OF OPERATION
2. 1 GENERAL
This section describes the operation of the Model 487 printer at the
functional block level and includes the active components within tne
functional block. Refer to Figure 2-1. The electronic control circuits for
the printer are primarily divided onto two p.c. boards: the Format
Controller and the Print Controller. The Format Controller accepts IBM
input data from the "host" system, serves as an interrace to the Print
Controller, and determines the operational functions for the printers. It
is also known as the ISI Interface PCB,
The Control Panel PCB contains the operator accessible controls and
indicators. These controls set-up the various printer functions via the
printing in the mechanism.
2.2 BASIC PRINTER OPERATION
The Format Controller supplies the operating parameters to the Print
Controller based on data received from the host device and the control
panel. These parameters are written into a shared Communication Random
Access Memory CC-RAM) on the Format Controller. The parameters are wri~ten
according to an address format, which is basically divided into two
sections. The first section is the Control Block and occupies memory
locations 0016 through OF16. This part of the memory is also referred to as
the print buffer. The second section is referred to as the Data Block.
The Control Block is dedicated to transferring a print command and paper
motion arguments from the Format Controller to the Print Controller and
transferring status information concerning printer action, paper motion and
self-test results from the Print Controller to the Format Controller.
The Data Block is dedicated to transferring information on printable data
from the Format Controller to the Print Controller. A detailed description
of the parameters, their bit structure, and input timing is found starting
with Paragraph 2.4.3 in the Paper Motion Argument Description.
- 11 -

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In order to discuss how data is processed in the printer, refer to Figure
2-2, Format Controller Bus Structure and Figure 2-3 Print Controller Bus
Structure, and assume that the printer has just been turned on. Turning
the printer on causes the microprocessor to go through an initialization
routine to set up its electronics and perform the folowing functions:
Raise the GOT IT line. The Address Bus
(DO-D7) are isolated from the buffered
information is conveyed to the Format
transferred.
(AO-A7) and the Data Bus
data bus (DBO-DB7). Signal
Controller that data cannot be
Lower WR line from the microprocessor. This line controls the chip
enable and read/write function of C-RAM.
- Move the print head to the extreme left margin, if not already there.
The C-RAM will clear and then write the printer status information
into C-RAM location 0016. The Address Bus CAO-A7) and the BData Bus
(BDO-BD7) are used by the CPU during the read/write functions to
C-RAM.
After the status information is loaded into C-RAM, the microprocessor
relinquishes control of the C-RAM to the Format Controller. This enables
the Format Controller to take control of the C-RAM with the CRSEL and HOLD
IT lines. The lowering of the GOT IT signals the Format Controller that it
has control of C-RAM and that the HOLD IT line will be monitored by the
Print Controller.
On recognition of the deactivated GOT IT line, the Format Controller will
then perform the following ructions:
Activate the HOLD IT line to establish that it has C-RAM control.
Polls the C-RAM status byte 0016 to check for the following:
1. there was an abort on an event,
2. the printer is out of paper,
3. a head jam, or
4. a failure during a requested self-test
Polls C-RAM Location 0116 and 0216 to determine how much paper has
been moved since the last top of form.
Polls C-RAM Location 0316 and 0416 to determine the number of paper
motion steps that were not completed during an aborted paper motion
event, if there was one.
After obtaining all the status information and taking the appropriate
action on it, the Format Controller can now load the parameters into C-RAM
to request various printer operations. The Format Controller writes each
- 13 -

parameter into C-RAM according to a certain format. This is done using the
Address Bus (AO-A7) and Data Bus (DO-D7) under the control of the SELECT,
RD, and WR control lines.
After the parameters are loaded into C-RAM, the Format Controller lowers
the HOLD IT line, indicating to the microprocessor on the Print Controller
that the parame~ers are loaded. The microprocessor activates GOT IT to
take control of C-RAM with the WR line and isolates the BData Bus from the
AO-A7 and DO-D7 input busses.
· Now that the microprocessor has control of C-RAM, the microprocessor
addresses the location of each of the five events in C-RAM starting with
Event 1. If data is stored in a location, it is acted on before proceeding
to the next location so that the five events are acted on in sequence.
These five events can cause
the
microprocessor to command the following
functions:
Event 1 - Reverse paper motion
before print.
Event 2 -Forward paper motion before print.
Event 3 -
Print Command.
Event 4 - Reverse paper motion after
print.
Event 5 -Forward paper motion
after
print.
To move paper in the forward direction or reverse direction, the
microprocessor will activate the V HOLD signal. This is followed by the
microprocessor applying pulses 01-04 on the 4-line bus to the stepper motor
driver circuit. The pulses are applied to the four phase inputs of the
paper feed stepper motor. This causes incremental motor shaft movement
(steps) in either direction, depending on the pulse sequence. The motor
shaft, in turn, drives the paper feed mechanism in the forward or reverse
direction to move paper at 0.0083 inch per step in fanfold mode and 0.00913
per step in cut sheet mode.
Before each step is executed, the microprocessor updates the status on
accumulated and uncompleted paper motion steps as described in this
chapter, Paragraph 2.4.3. If the microprocessor detects a paper out
condition during the paper movement operation, the microprocessor will
deactivate the stepper motor to stop paper movement and will recognize the
situation as an abort during the event. The abort condition is written
into the Printer Status byte in C-RAM before the microprocessor returns
control of C-RAM to the Format Controller.
The Format Controller can load arguments into C-RAM for events 1, 2, 4,
and 5 to request paper movement from 1 step to 4,095 steps (0.0083 to
17.062 inches) in each event. Refer to Paragraph 2.4.3 for details on the
paper movement arguments.
- 14 -