Centronics 101A User manual

MODEL 101A PRINTER
REVISION G
DEC. 1974
THE INFORMATION CONTAINED HEREIN IS
PROPRIETARY AND IS NOT TO BE RELEASED
OR REPRODUCED WlrTHOUT WRITTEN PER-
MISSION OF CENTRONICS data computer corp.
I:EnTRDnll:S
data computer corp.
HUDSON, NEW HAMPSHIRE 03051
TELEPHONE [phone]

TABLE OF CONTENTS
SECTION 1
INTRODUCTION
1.1 GENERAL DESCRIPTION
1.2 LOGIC FLOW DIAGRAM
1.3 PRINTER OPERATION ..
1.3.1 Character Printing.
1.3.2 Paper Movement ...
1.3.3 Special Functions.
1.4
PHYSICAL DESCRIPTION ..
1.5 SYSTEM CHARACTERISTICS ..
1.5.1 Standard Features ..
1.5.2 Optional Features.
SECTIONS 2 AND 3
INSTALLATION AND OPERATION
2.1 SITE PREPARATION.
2.2 SHIPPING CRATE .
2.3 PAPER GUIDE AND STACKER ASSEMBLY ..
SECTION 4
THEORY OF OPERATION
4.1 INTRODUCTION . • . . . •
4.2
BASIC TIMING ..... .
4.3
INITIALIZING THE PRINTER ..
4.3.1 Prime Circuit ...
4.3.2 Select Circuit ..
i
Page
· 1-2
· 1-3
· 1-4
· . . 1-4
· . . . . 1- 5
· . . . . 1-6
· . 1-7
· 1-7
· . 1-8
· 1-13/1-14
· .
2-1
· 2-2
· . 2-3/2-4
· . .
4-1
· . 4-3
· . . . . 4-3
· . . 4-4
· . . 4-7
Rev. C

TABLE OF CONTENTS (cont'd)
Section
4.4
LOADING DATA
4.4.1
General
. · · · · · ·
4.4.2
Data Strobe · · · · · ·
4.4.3 Acknowledge
·
4.4.4
Busy Timing
· · · · · · · · · · · ·
4.4.5
Clocking Input Data Into the Buffer
4.4.6 Function
Decoder.
4.5 CHARACTER PRINTING
· · · · · · · ·
4.5.1
Initiating the Printing Operation
4.5.2 Print
Head Motion
· · · · · · · ·
4.5.3 Character Registration
and Timing
·
4.5.4 Character Generator (ROM)
· · · · ·
4.5.5 Print Head Operation. · · · · ·
4.5.6
Power Driver Circuits · · · · · · ·
4.5.7 Terminating the Printing Operation.
4.6
PAPER MO'JEMENT
. · · · · · · · · ·
4.6.1·
Line Feed
· ·
4.6.2
Form Feed
· · · · · ·
4.6.3 Vertical Tab.
· · · ·
4.6.4 Vertical Format Unit. · · · ·
4.6.5
Paper Time Out Circuit ..
4.6.6 Line Feed Solenoid Driver · · · ·
4.7
SPECIAL FUNCTIONS
· · · · ·
4.7.1 Bell ... .
4.7.2 Delete
... .
4.7.3
Paper Empty ........ .
4.7.4
Motor Control (Optional) .. .
4.7.5 Fault
Circuit. . .... .
4.8
POWER SUPPLIES . . . .
4.8.1
+5V Regulator ..... .
4.8.2
+12V and -12V Regulators ...
4.8.3 +35V Power Supply, Unregulated.
ii
·
·
·
· ·
·
· ·
· ·
·
· ·
· · ·
· · ·
· · ·
· · · ·
· ·
· ·
· · · ·
· · ·
Page
· 4-10
4-10
·
4-10
·
4-13
· · · D
4-13
· ·
4-16
4-18
· ·
4-19
·
4-19
4-21
· $
4-21
· · ·
4-26
·
4-27
· · ·
4-29
· 4-30
· ·
4-31
· ·
4-31
· 4-33
· 4-35
· · ·
4-36
· · · · ·
4-37
· · · ·
4-37
·
4-37
· . . 4-37
· . . . . 4-37
· . 4-39
· . 4-39
· 4-43
4-43
· 4-46
4-47/4-48
4-47/4-48
IRev. 0

TABLE OF CONTENTS (cont'd)
SECTION 5
REMOVAL, REPLACEMENT AND ADJUSTMENT PROCEDURES
Sect-ion
5.1
5.2
6.1
6.2
INTRODUCTION
MECHANICAL ASSEMBLIESJ .
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7
5.2.8
5.2.9
5.2.10
5.2.11
5.2.12
5.2.13
Cover. . • . • . . .
Carriage
Mechanism ...
Driving Mechanism ..
Spring Drum ....•
Damper . . . . . . . . . . . • • . .
Frame. . . . . • . . .
Paper Feed Mechanism ..
Pin Feed Unit. . . • .
Form Feed Mechanism ..
Ribbon Feed Mechanism ..
Electrical Hardware ....
Paper Stacker and Guide. . . . . . . .
Print
Head and Associated Assemblies
SECTION 6
MAINTENANCE
ADJUSTMENTS ...•...
PREVENTIVE MAINTENANCE
SECTION 7
DRAWINGS AND PARTS LISTS, ELECTRICAL
SECTION 8
DRAWINGS AND PARTS LISTS, MECHANICAL
111
Page
· .5-1
.5-1
.5-3
· .5-4
· .5-8
. . . .5-
20
.5-21
..• 5-22
.5-26
.5-27
.5-30
.5-34
..... 5-43
· .5-43
· .5-44
· .6-1
.6-2
Rev. F

Figure
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
2-1
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
ILLUSTRATIONS
Model lOlA Printer (Front Cover Removed) .
Basic Block Diagram ...
Print Head Components ..•.
Printing the Letter (H).
Paper Movement Mechanism .
Left Front
View of lOlA Printer ..
Right Front View of lOlA Printer .
Rear View of lOlA Printer .....
Rear View (lOlA Electronics Cavity Removed).
Printer Dimensions . . . . . . . . .
Model lOlA Functional Block Diagram.
Functional Flow Chart ..
Basic Timing Circuit
Prime Timing . .
Prime Circuit ... .
Select Circuit
... .
Input Data Timing -No Busy Condition
Data Input Circuit
Acknowledge Circuit ...
Input Data Causing Busy __ .
Busy Circuit .•..•..
Function Decoder . . . .
Character Printing
Block Diagram
Forward and Reverse Clutch Drive Circuits.
Character
Timing . . . . . . . . . . . . .
Character Registration
and Timing Circuit ..
Normal and Elongated Characters ..
Solenoid Positions, 1 through 7 ..
Print Head Timing ..••
Power Driver Waveform. . . . . . .
iv
Page,
D 1-2
" 1-3
. . .
~ 1-4
• • • • • II 1-4
· 1-5
· . 1-9
· . 1-10
·
1-11
· 1-12
·
2-1
· 4-1
· 4-2
· . 4-3
· . . 4-4
4-5/4-6
· 4-8
4-10
•
.4-11/4-12
• • • 4-13
• 4-14
· . 4-151
4-17'
· 4-19
· 4-20
·
4-2~~
· 4-23/4-24
•
4-27'
· 4-28
· . . 4-28
· . 4-29
Rev. C

4-21
4-22
4-23
4-2L~
4-2E>
4-26
4-27
4-28
4-29
4-30
4-31
5-1
5-2
A
5-3
5-4
5-4A
5-5
5-6
5-7
5-8
5-9
5-10
5-11
7-1
7-2
7-3
7-4
7-5
7-6
7-7
LIST OF ILLUSTRATIONS (cont'd)
Line Feed Circuit.
Line Feed Timing.
Form Feed and Vertical Tab Circuit.
Form Feed and Vertical Tab Timing .
Bell
Circuit .
Paper
Empty
Location of Motor Control Circuit .
Motor Control Board Interconnection Diagram .
Motor Control Timing.
Fault Circuit.
Power Distribution Diagram.
Series 101 Drive Train, Main Motor and Clutches.
Drive Mechanism - HB
Use of Feeler Gauge for Backlash Adjustment.
Page
4-32
4-33
4-34
4-35
4-38
4-40
4-41
4-41
4-43
4-44
4-45
5-8
5-14
5-18
Flexible Timing Fence Mounting, Series 101 . 5-23
Location of Left Reed Switch (Front View). 5-25
Two Adjustments, Gear with Stop Cam (HH-23) & Cam(HH-14)5-32
Ribbon Feed Mechanism (Rear of Printer, Left Side). 5-38
Backlash Adjustment, Bevel Gear (HI-43, 59) . 5-39
Driving Slide Shaft A - Adjustment.
Ribbon Reversing Rod Adjustment
Ribbon Reverse Timing
Fiber Optics Head (& Bundle), Adjustment from
Optic Fence.
Fibre Optics
Head Alignment &Flexible Timing Fence
Level Breakdown Chart, 101/101A .
Schematic Electronic
Card No. l(Sheet 1 of 3)
Schematic Electronic Card No. 1 (Sheet 2 of 3) .
Schematic Electronic
Card No. 1 (Sheet 3 of 3) .
Schematic Electronic Card No. 2 (Sheet 1 of 3) .
Schematic Electronic
Card No. 2 (Sheet 2 of 3) .
Schematic Electronic
Card No. 2 (Sheet 3 of 3) .
Schematic
Power Driver Board (Sheet 1 of 2)
v
5-40
5-41
5-41
5-48
5-48
7-3
7-5
7-6
7-7
7-8
7-9
7-10
7-11
REV. E

Figure
7-8
7-9
7-10
7-11
7-12
7-13
7-14
7-15
7-16
7-17
7-18
7-19
7-20
7-21
7-22
7-23
7-24
7-25
7-26
7-27
7-28
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
8-11
8-12
LIST OF ILLUSTRATIONS (cont'd)
Schematic
Power Driver Board (Sheet 2 of 2) .
Schematic
+5 Volt Regulator
Schematic
~12 Volt Regulator.
Schematic Video Amplifier
Multitap 50/60
Hz Transformer.
Schematic,
Motor Control
Wiring Diagram, Printer Mechanism .
Interconnection
Diagram, Connector Board (lOlA).
Component Card Assembly, No.1.
Component Card Assembly, No.2.
Component Board Assembly, +5 Volt Regulator .
Component Board Assembly, ±12 Volt Regulator.
Component Board Assembly, Connector Board
Component Board Assembly, Power Driver Board .
Video Amp 1i fier and Cable ASSE!mb 1y .
Electronics Cavity Assembly
Harness (WI) Assembly .
Computer I npu t Cab 1e (W2) AssE~mb ly .
Power Cable (W3) Assembly .
Component Board Assembly, Motor Control
Motor Control Harness Assembly .
Foam Cover Assembly (A)
Carriage Mechanism (HA)
Drive Mechanism (HB)
Spring Drum (HC)
Damper (HD)
Frame (HE) .
Paper Feed Mechanism (HF) .
Pin Feed Mechanism (HG).
Form Feed Mechanism (HH)
Ribbon Feed Mechanism (HI).
Electrical Hardware (NO DRAWING) (HJ) .
Print
Head and Associated Assemblies .
vi
Page
7-12
7-13
7-14
7-15
7-16
7-17
7-18
7-19/20
7-21
7-23
7-25
7-27
7-29
7-31
7-33
7-35
7-37
7-39
7-40
7-41
7-43
8-3
8-5
8-7
8-9
8-11
8-13
8-15
8-17
8-19
8-21
8-23
8-24
REV. E

SECTION I
INTRODUCTION
This manual describes the Model lOlA printer, manufactured by Centronics
Data Computer Corporation. It provides general information, detailed theory of
operation
and maintenance information enabling field service personnel to main-
tain the printer. For serial input or other detailed interface information, a
separate
document for each interface is published for your reference.
pose.
The manual is grouped into eight sections, each with its specific pur-
Section I -
INTRODUCTION~ introduces the reader to the scope and
content of the manual, and provides the reader with
a general description of the printer.
Section 2 &3 -
INSTALLATION & OPERATION, contains additional in-
stallation and operation data not included in the
Operators
Manual.
Section 4 -
Section 5 -
Section 6 -
Section 7 -
Section 8 -
THEORY OF OPERATION, contains a detailed description
of
each major operation performed by the printer
electronics, including
flow chart, timing diagrams
and circuit diagrams.
REMOVAL, REPLACEMENT AND ADJUSTMENT PROCEDURES, includes
step-by-step
removal and replacement proc~dures for all
major assemblies and sub-assemblies in the printer.
MAINTENANCE, includes preventive maintenance procedures,
and recommended spare parts list.
ELECTRICAL DRAWINGS AND LIST OF MATERIALS, contains a
complete set of schematic, wiring and component board
layout diagrams and their associated list of materials
for the electrical portion of the printer.
MECHANICAL DRAWINGS AND PARTS LISTS, includes all
printer assembly drawings and their associated part
lists for the mechanical portion of the printer.
1-1 Rev. C

At the end of the manual are several appendices which include a g'lossClry
of signal mnemonics, standard 9 x 7 character set, and parallel interface spec-
ifications.
1.1 GENERAL DESCRIPTION JFigure 1-1)
The Model lOlA printer is a medium speed impact printer which uses a
9 x 7 dot matrix for character generation.
Figure 1-1.
MODEL lOlA PRINTER (FRONT COVER REMOVED)
The unit prints at a rate of 165 characters per second with an average
speed of 132 characters per second (including the return time for the printing
head).
The printer 1s capable of printing 1~12 columns, with paper width varying
from 4 inches to 14-7/8 1nches. The unit uses sprocket-fed paper w1th 6 lines
to the inch vert1cally
and 10 characters per inch horizontally. The printer
does not require special paper and can produce an original plus four copies.
1-2 Rev. C

1.2 bOGIC FLOW DIAGRAM (Figure 1-2)
The 132-character input buffer can receive parallel data at a rate of
up to 75,000 characters per second. If the input device transmits serial data
(100-9600 Baud), then an optional RS232 interface is required to'assemble the
serial data, then transfer it in parallel to the input buffer in the printer.
PARALLEL INPUT (STANDARD)
RATE = 75,000 CHARACTERS PER SECOND
MARK = BINARY 1=+2.4 to 5.5 VOLTS
SPACE = BINARY 0 = 0 TO +0.4 VOLT
DATA STROBE~
ACKNOWLEDGE ~
RS232 SERIAL INPUT (OPTIONAL)
BAUD RATE = 100-9600
START PULSE = ONE BIT TIME
STOP PULSE = MIN. OF ONE BIT TIME
MARK = BINARY 1 = -3 TO -27 VOLTS
SPACE = BINARY 0 = +3 TO +27 VOLTS
1. PRINT COMMAND
(CR OR LAST CHAR.)
2. PAPER MOVEMENT
(LF, VT, FF)
3. SPECIAL FUNCTIONS
(BELL, DELETE, EXP.
CHAR, SELECT, DESELECT)
Figure 1-2. BASIC BLOCK DIAGRAM
HEAD MOTION
CONTROL
PAPER MOTION
CONTROL
TIMING
Once a line of printable characters is stored in the buffer, head
motion is initiated by activat1ng the forward clutch, causing the print head
to move from left to right across the paper. With the head in motion, data is
transmitted from the buffer to the character generator. From there, character
write pulses are sent to the driver circuits, which energize the print head
solenoids causing the print wires to form the characters on the paper.
Paper movement is initiated by a line feed, vertical tab and form feed
function. The Vertical Format Unit (VFU) tape reader provides vertical tab
and top of form spacing control by means of a perforated paper tape.
In addition, the printer recognizes the following special control codes:
bell, delete, select~ de-select and elongated character, as described in
Section 1.3.3.
1-3
Rev. C

1.3 PRINTER OPERATION
Basically, all printer functions can be grouped into one of the follo\«Iing
three categories: 1) character printing, 2) paper movement, and 3) other aux··
iliary functions such as printer select/deselect, delete, etc.
1.3.1 CHARACTER PRINTING (Figures 1-3, 1-4)
The print head (Figure 1-3) consists of the jewel, casting and seven
solenoids with attached print wires. The seven print solenoids and their attached
print wires are arranged
radially around the print head. The free ends of thE!
print wires pass through a wire guide at the front of the print head, which pro-
perly spaces the wires
so that the correct wtre passes through the correct hole
in the
print jewel.
JEWEL
<-----A _----I
Figure 1-3. PRINT HEAD COMPONENTS
Figure 1-4. PRINTING THE LETTER (H)
1-4
Rev. C

A small aluminum carriage supports the print head assembly. During
printing operation, the carriage travels along the print line from left to
right. Printing is accomplished by selectively firing the print wires as
the
print head moves from left to right across the print line. Printing im-
pulses energize the print solenoids and drive the print wires against the
ribbon, paper and platen to form the characters in a dot matrix pattern. When
the solenoids are de-energized, the wires are withdrawn so they are flush with
the surface of the jewel.
Each solenoid can fire independently up to five
times for anyone character. Figure 1-4 shows an example of the dot matrix
forming the letter H. All character formations in the standard 9 x 7 dot matrix
are
shown in Appendix B.
Printing action is initiated when the input buffer has been filled or
a carriage return
(CR) code has been received. The print head then sweeps
across the page until a CR command is decoded at the buffer output or the head
reaches the 132-column limit (right) switch. At this time, the print head re-
turns to the left margin and an automatic line feed is performed. As an option,
the automatic
line feed can be disabled.
1.3.2
PAPER MOVEMENT (Figure 1-5)
Paper can be moved manually by rotating the platen knob or automatically
by any of three paper movement commands: line feed, vertical tab and form feed.
PAPER
ADVANCE
Figure 1-5. PAPER MOVEMENT MECHANISM
1-5
Rev. C

A small independent motor not shown in Figure 1-5, provides the powe,r
necessary to move the sprocket-feed tractors which control paper movement.
To move the paper, the printer electronics activates a line feed solenoid
which activates a clutch that mechanically 'links the motor to the sprocket-
feed
tractors.
To initiate a single line feed, the form feed solenoid is energized
for
15 milliseconds. For paper slewing, a dc level is applied to the form
feed solenoid allowing paper to advance unt'il the Vertical Format Unit (VFU)
deactivates the level. Upon completion of the line feed command, a 60-90
milJis~cond delay is generated. This allows the clutch Ipawl and clutch
mechanism to return home before another line feed is allowed.
To initiate a single line feed, the' form feed solenoid is energized
for
15 milliseconds. For paper slewing, a dc level is applied to the form
feed solenoid allowing paper to advance until the Vertical Format Unit (VFU)
deactivates the level.
The VFU is controlled by a paper tape, which uses one track for
top of
form indication and one track for vertical tab. The movement of
the paper tape
is caused by direct mechanical linkage to the gear train
which drives the paper feed tractors.
When the printer runs out of paper, a sensing switch activates a
two-second audible tone in a speaker locate,d at the rear. The printer also
stops printing
and lights the PAPER EMPTY light on the control panel.
1.3.3
SPECIAL FUNCTIONS
In addition to the printable characters shown in Appendix B, the
printer can recognize the following special functions:
Carriage return (Octal
015) - Initiates the printing of a line.
Form Feed (Octal 014) - Moves the paper until the next hole in Tape
Reader Channel 7 is reached.
Vertical
Tab (Octal 013) - Moves the paper until the next hole in Tape
Reader Channel 5 is reached.
Line Feed (Octal 012) - Advances the paper one line.
Delete (Octal 177) - Initializes the printer electronics and clears the
buffer.
Bell (Octal
007) -Generates a two-second audible tone in the speakelr
at the rear of the printer.
Select (Octal 021) - Allows printer to receive data, same as activating
SELECT switch.
De-Select (Octal
023) -Inhibits printer from receiving data, same as
deactivating SELECT switch.
1-6 RE!V. D

1.4 PHYSICAL DESCRIPTION (Figures 1-6 through 1-9)
The printer is approximately 11-~1I high, 20" deep, 27-3/4" wide and
weighs approximately 118 pounds. The referenced figures contain different
photographic views of the printer taken with the covers removed. Each major
printer assembly is located on these figures and identified in the table below
the photo.
1.5
SYSTEM CHARACTERISTICS
Table 1-1 summarizes the major characteristics of the Model lOlA printer:
Table 1-1
Model lOlA Characteristics
Printing
Rate -Characters
Lines
Transmission Rate -Serial
Parallel
Data Input
Character Structure
Input
Language
Paper Requirements
Paper Feed
Switch Controls
Indicators
Manual Controls
Character Buffer
Printing Structure
Dimensions
(cont'd next page)
165 characters per second
60 lines per minute (132 character line)
200 lines per minute (20-30 characters)
100 to 9600 baud (with Serial option)
Up to 75,000 characters per second
Parallel (Serial option available)
9 x 7 dot matrix -
10 point type equivalent
USASCII - 64 characters printed
Standard sprocketed paper, original
and up
to four carbon copies
Pin Feed, adjustable from 4" to 14-7/8"
width
ON/OFF, SELECT, TOP OF FORM, FORMS OVERRIDE,
LINE FEED
PAPER OUT, ON/OFF, SELECT
Forms Thickness, Paper Advance Knob
132 character buffer (1 line)
132 characters per line, 6 lines per inch
11-~1I high, 20
11
deep, 27-3/4
11
wide
(weight 118 pounds)
1-7
Rev. (

Table 1-1
Model lOlA Characteristics
Special Interface Options Special interfaces to popular
computers -
communications options
Temperature
Operating: 40
0 to
100
0 F
Storage:
-40
0 to
160
0 F
Humidity (%RH)
Operating:
Storage: 5 to
90% (no condensation)
oto 95%
Electircal Requirements
1.5.1 STANDARD FEATURES
Standa.rd:
117 VAC ±10% 60 Hz or,
117/234 VAC t10%, 50 Hz
The following is a list of standard features in the Model lOlA printer:
• Vertical format control using
two channel paper tape loop (one channel
for vertical tab, the other for form feed control).
•
Audio alarm buzzer generates two-second audible tone whenever paper run$
out or Bell code (octal 007) is received by printer.
• Elongated boldface characters on a line,-by--line basis, initiated by an
octal 016 code.
•
Paper runaway inhibit usually set to six seconds which is approximately
1~ forms.
• Gated strobe pulse (data input) prevents a new character from being
accepted until the previous character has been acknowledged.
• Separate prime line and fault line to interface connector.
•
Remote printer select (octal 021) and de-select (octal 023).
• Parallel interface
accorrmodating data input up to 75,000 characters per
second.
•
Automatic line feed following carriage return.
•
Fixed vertical spacing of 6 lines per inch and fixed horizontal spacing
of
10 characters per inch.
1-8
Rev. C

::;:0
(J)
<
n
1. Print Head Assembly
2. Carriage
3. Form Feed Mechanism
5
4. VFU Tape Reader
7. Spring Drum
10. Timing Fence
5. Pin Feed Mechanisms 8. Platen Knob 11. Main Drive Belt
6. Ribbon Feed Mechanism
9. Damper
Figure 1-6. LEFT FRONT VIEW OF lOlA PRINTER

I--'
I
I--'
o
::;c
CD
<
n
(NOT ON 101)
1. Operator Control Panel 5. Optical Pick-Up
2. Form Feed Motor 6. Optic Bundle
9. Penetration Control Knob
10. Forward Clutch
3. Video Amplifier and Cable Assembly 7. Ribbon Cable
11. Main Pulley and Drive Belt
4. Light Source 8. Power Driver Board
12. Reverse Clutch
Figure 1-7.
RIGHTjRONT VIEW OF lOlA PRINTER
13. Cooling Fan
14. Ribbon Feed
Mechanism
15. Line Feed

7
1.
Electronics Cavity 4. +5VDC Power Supply 7.
Input Connector
10.
Fuses
2. Electronic
Card
1
5.
±12VDC
Power Supply
8.
Speaker
11.
In-Line Fuse
:::0
3. Electronic Card
2 6. +30 Volt Power SupplJ
9.
AC Power Input
CD
<
.
('"')
l:":~~re
1-8. REAR
VIE~r Co:"
::1 ~
';RINTER

......
I
......
N
::;::0
rD
<
1. Main Motor 4. Electronics Connector 7. Ribbon Reversing Rod
2. Motor Starting Capacitor 5. Power Transformer
8. Ribbon Drive Rod
3. AC Power Connector
6. Power Distribution
Figure 1-9.
REAR VIEW (lOlA ELECTRONICS CAVITY REMOVED)