Radio Shack 26-1154A, line printer II TRS-80 Service Manual

LINE

PRINTER

n

Catalog

Number

26-1

154A

mmmm\

USS

NOTE

The

purpose

of this

manual is twofold.

It

provides the

owner with

complete

adjustment procedures

and it

provides Radio Shack

Service Personnel

with

complete repair

procedures.

If

you are

not technically inclined,

do not attempt

to repair

your Printer. If

you do,

you'll void your warranty.

TABLE

OF

CONTENTS

SECTION

1

INTRODUCTION

Section

1.1

SCOPE

1.2

GENERAL

DESCRIPTION

1.3

PHYSICAL

DESCRIPTION

1.4 FUNCTIONAL

DESCRIPTION

1.5

SPECIFICATIONS

SECTION

2

INSTALLATION

2.1

INSPECTION

2.2

INTERFACE

INFORMATION

2.2.1

Printer

Interface

Connector

.

2.2.2

Interface

Connector

Pin-Outs

.

2.2.3

Interface

Drivers

and

Receivers

.

2.2.4

Interface

Communication

and

Timing

2.2.5

Host-Generated

Control

Codes

.

2.2.6

ASCII

Code

Charts

2.3 AUTO

LINE

FEED

ENABLE/DISABLE

....

2.4

CHARACTER

SET

SELECTION

SECTION

3

THEORY

OF

OPERATION

3.1 BASIC

DESCRIPTION

SECTION

4

MAINTENANCE

4.1

GENERAL

4.2

PREVENTIVE

MAINTENANCE

4.3

OPERATOR

TROUBLESHOOTING

Page

1-1

1-1

1-2

1-4

1-7

2-1

2-1

2-1

2-2

2-2

2-3

2-4
2-5

2-9

2-9

3-1

4-1

4-1

4-3

-l-

TABLE OF CONTENTS

(cont'd)

Section

Page

4.4

FUSE REPLACEMENT 4-4

4.4.1

Removal

of Covers 4-4

4.4.2 Fuse Replacement

4-6

4.5

DETAILED TROUBLESHOOTING 4-7

4.6

GENERAL CLEANING AND LUBRICATION 4-10

SECTION

5

ADJUSTMENTS

5.1 INTRODUCTION

5-1

5.2

TOOLS AND

ACCESSORIES

5-1

5.3

PRINTHEAD

GAP ADJUSTMENT 5-2

5.4

PLATEN

ADJUSTMENT 5-2

5.5 ROTOR/HALL EFFECT

SENSOR ADJUSTMENT 5-3

5.6 LINE FEED

SOLENOID ADJUSTMENT 5-3

5.7 PRINT DENSITY

(SPEED) ADJUSTMENT 5-4

SECTION

6

REMOVAL AND REPLACEMENT

6.1 SCOPE

6-1

6.2 MECHANISM ASSEMBLY

6-1

6.3

PCB

LOGIC BOARD 6-3

6.4 LINE FEED SOLENOID ASSEMBLY 6-5

6.5 CARRIAGE

RACK, MOLDED

.

6-5

6.6 BASE COVER

ASSEMBLY

6-7

6.7 BODY

COVER

ASSEMBLY 6-7

6.8 HEAD

CARRIAGE ASSEMBLY 6-9

6.9 PLATEN ASSEMBLY.

6-10

SECTION

7

SUPPORTING ILLUSTRATIONS

-ii-

TABLE

OF

CONTENTS

(cont'd)

SECTION

8

ILLUSTRATED

PARTS

BREAKDOWN

Section

Page

8.1

INTRODUCTION

8-1

8.2

ABBREVIATIONS

8-1

8.3

MECHANICAL

PARTS

BREAKDOWN

8-4

8.3.1

Figure

and Item Number

8-4

8.3.2

Part Number

8-4

8.3.3

Description

8-4

8.3.4

Quantity

8-4

8.4 ELECTRICAL

PARTS

BREAKDOWN

8-22

8.5

NUMERICAL

INDEX

LIST

8-27

8.5.1

Part

Number

.

8-27

8.5.2

Description

8-27

8.5.3

Figure

and

Item Number

8-27

8.5.4

Quantity

8-27

APPENDIX

A

ADJUSTABLE

PIN-FEED

DRIVE

ROLLER

-ill-

LIST OF ILLUSTRATIONS

Figure

Page

1-1

Printer

Assemblies

1-3

1-2

Pictorial Schematic

1-5

2-1

Top

View

of Printer Interface

Connector

2-1

2-2

Interface Drivers and Receivers

2-2

2-3

Interface Timing

2-4

2-4

ASCII Code

Chart

(U.S.A., France)

2-6

2-5

ASCII

Code Chart

(United Kingdom, Germany)

2-7

2-6

ASCII

Code Chart (Italy,

Sweden/Finland)

2-8

2-7

Setting

Auto Line Feed and Character Set Switches ....

2-9

3-1

Line

Printer II Basic Block Diagram

3-1

3-2

Line Printer

II

Character Styles

3-3

3-3

Interface Timing

3-4

3-4

Acknowledge Timing on

Power-Up

3-5

4-1

Replacement of

Fuse F1

4-5

6-1

Mechanism Assembly

Replacement

6-2

6-2

Logic

Board

Replacement

6-4

6-3

Line Feed Solenoid Replacement

6-6

6-4

Carriage Rack Replacement

6-6

6-5

Base and Body

Cover

Assembly Replacement

6-8

6-6

Head-Carriage Assembly Replacement

6-10

6-7

Platen Assembly Replacement

6-11

7-1

PCB Part No. 63669422 Schematic Diagram

7-2

7-2

PCB Part

No.

63669416 Scrematic Diagram

7-3

8-1

Line

Printer II Major Assemblies

8-4

8-2

Body Cover Assembly

8-6

8-3

Mechanism Assembly

8-8

8-4

Printer Head/Carriage Assembly

8-12

8-5

Left/Right Side Plate Assemblies

8-14

8-6

Base

Cover Assembly

8-16

8-7

Paper Roll

Holder Assembly

8-18

8-8

Main Acoustic

Kit

8-20

8-9

Logic P.C.B. Assembly

8-22

-IV-

SECTION

1

INTRODUCTION

1.1

SCOPE

This

manual

contains

detailed

information

on the

installation,

theory

of

operation,

maintenance,

and

adjustment

of

the Radio

Shack

Line

Printer

II

dot-matrix

printer.

The

contents

of

the

manual

are for

use

by

qualified

service

personnel who

have

been

trained

to

maintain

and

repair

electronic

and

electromechanical

equipment.

Care

must

be

exercised

when

servicing

the

printer

to

avoid

possible

damage

to the

printer

or injury

to

personnel.

1.2 GENERAL

DESCRIPTION

The

Line

Printer

II

is

an

operationally

simple,

compact,

microprocessor

controlled,

dot-matrix,

impact

printer.

The

unit

prints

7x7 dot

matrix

characters

at

10 or 16.7

characters

per

inch

in

line

lengths

up

to

8 inches

at

a rate

of

100

characters

per second.

The

printer

features

three-way

paper

handling.

(1) 9

1/2-inches

(9-inches

pin-to-pin)

wide

standard

computer

fanfold

forms, with

fixed

position

pins

to

ensure

pinfeed

paper

registration.

The

paper can

be

multipart

up

to three

parts.

(2)

Rolled

paper,

3

1/2-to

8

1/2-inches

wide,

1-inch

core

and up

to

5-

inches

diameter.

The

printer

includes

a

roll

paper

holder.

A

built-in

rip-and-read

cutting

edge

allows

easy

removal of

paper.

The

first

line

of following

page is

printed

within

five

lines

of

tear

edge. Two

ply paper

may

be

used

with

operator

attendance.

(3)

Single

sheets

of

8 1/2-inch

wide

paper,

hand

fed

as with

an

ordinary

typewriter.

The

printer

contains six

dip

switch

selectable

character

sets

of the

following

countries:

U.S.A.,

France,

United

Kingdom,

Germany,

Italy

and

Sweden/Finland.

Characters

are

printed

at

up to

80

characters

per

line in

the

10

cpi

character

density

and

up

to 132

characters

per line

in

the

16.7

cpi

character

density.

Elongated

characters

are

double-width

characters

and

can

be printed

in

either

the

10

cpi

or 16.7

cpi

character

density.

Other

significant

features

include:

(1)

Reliable

free-flight

head.

(2)

Microprocessor

technology.

(3)

Full

line buffer.

(4)

Fast

carriage

return

at 10

inches

per

second.

(5)

Special

line

feed buffer

for

host-controlled

forms

control.

(6)

Compact

size

(5-inches high

x 14

1/2-inches

wide

x

11-inches

deep)

1-1

1.3 PHYSICAL DESCRIPTION

A

printer mechanism, printed circuit

board, cover

assembly set,

and

holder

for roll

paper

comprise the major assemblies of the

printer. See

Figure

1-1.

The three cover set

provides structural

support

and consists

of a

base cover,

a body cover, and

a

top

cover. The

base

cover supports

the

printed circuit

board

and the printer

mechanism.

The body

cover fits over

and

around the base

cover and contains

a

flat

tray for

the ribbon.

It also

houses

the ribbon

drive motor

and gear mechanism.

The top

cover snaps into

the body

cover

and

prevents contact with the

print

mechanism

and electronics.

Printed

paper exits through

a slot

in

the rear of the

cover which

has

a

serrated

edge

to provide

a tear bar for removing

printed pages.

The printed

circuit board

(pcb) contains

all the

printer

electronics

including

an "on board" DC

power

supply

with

an input

transformer, filter

capacitors,

and fuse.

The pcb fits underneath

the

printer mechanism

and

is

approximately

the

same size as the bottom

cover although

the

electronic

circuitry

requires only about

one-third of

this

area.

This

allows the printed

circuit

input edge card

connector, which

protrudes from the

bottom

rear of the

printer,

to be an integral

part

of

the

pcb

for

increased

reliability. It

also

allows the POWER ON/OFF

and ONLINE/OFFLINE

switches, which

protrude

from

the

bottom

front to

be

mounted

directly on

the pcb.

The printer

mechanism

consists of

a left

and right

end plate which

secure

the carriage assembly shafts

and

carriage

rack, the platen,

and the

paper feed

roller

assemblies. A solenoid

attached to the left

end plate

provides the

drive for

paper movement. The

solenoid is

mechanically

linked by

a

pawl which

engages a ratchet

on the

paper feed roller.

When the

solenoid is

energized

the

paper feed roller is

rotated

incrementally resulting

in

a

forward

(upward) movement of

paper one-sixth

inch

(4

mm) or one

line.

The

carriage assembly is

driven

back and

forth on the

carriage

shafts

by the

drive motor pinion

gear which engages

the

rack. The

print head

is

transported

along the

platen

by

the motion

of the

carriage

assembly. A

flexible

cable

connects the drive motor

and print

head solenoids

to the

pcb.

1-2

00899

PAPER

EXIT

SLOT

ONLINE/OFFLINE

SWITCH

SERRATED

EDGE

PRINTED

CIRCUIT

BOARD (PCB)

BODY

COVER

PRINTER

ASSEMBLY

POWER

ON/OFF

SWITCH

Figure

1-1.

PRINTER

ASSEMBLIES

1-3

1.4 FUNCTIONAL DESCRIPTION

Figure

1-2

is

a pictorial diagram

of

the Line

Printer

II. All

of

the logic,

control, and power supply

circuits

are contained

on

the logic

pcb

(printed circuit

board)

.

The printer

employs

a microprocessor

located

on the

logic pcb to control

printer operation.

Under

program

control

the

micro-

processor controls

the

receiving

of input

data

from

the host

device,

monitors

printer

status,

initiates and controls

movement

of the

carriage

assembly,

controls

printing

by

the print head,

and

controls

paper movement.

It monitors

the

position

of the

print head

at

all times

and

provides

printer

status

information

to the host

device.

The host

device

transmits

8-bit

parallel

(ASCII)

data and

a data

strobe

signal

to the

printer logic

pcb.

Control

of the

transmission

of data

betwe

en the

host

device and

the printer

accomplished

using

the

acknowledge

(ACK)

,

BUSY,

and DEMAND

signals.

Data

tra

nsmitted

by

t

he

host

device

is

strobed

into

the

logic

pcb circuits

by the DATA

STROBE

signal.

The

printer

responds

by sending

a

BUSY

signal to

host

device

indicating

printer

is opera-

ting

on the

data. After

processing

the data

the

printer

sends

an acknowledge

signal

to

the

host and the

BUSY signal

is

discontinued.

The DEMAND

signal

is

the

inverse

of the

BUSY signal

and when

present

indicates

to the

host that the

printer

is

not

busy and

can accept

data.

The input

data

applied to

the

printer consists

of

character

data and

control

code data.

Character

data

is

stored

in an

input

buffer

until

the data

is

to be printed.

Control codes

are

interpreted

as

instructions

by

the

printer

and provide

the

means for

host

control of

the

printer.

Input

character

data is

stored in

the

input

buffer

until

the buffer

is full,

or until

a carriage return

(CR)

control

code

is received.

A

CR

control

code

is

interpreted as

a print

command

by the

printer.

Receipt

of a

CR

control

code by the printer

intitiates

printing

of the

contents

of the

input

buffer.

Printing is

also initiated

when

the

input

buffer

becomes

full.

In the

10 cpi mode buffer

full is

80

characters

while in

the

16.7 cpi

mode

buffer full

is

132 characters.

Characters

are printed by

selectively

energizing

the

print head

solenoids

which

in turn activate

the

pins of

the

print head

which

are arranged

in

a column.

As the

print head is

moved across

the

paper the

appropriate

pins

are

activated

driving

them against

the ribbon

paper,

and

platen to

form

characters

in

a 7x7 dot

matrix.

The

print

head is

mounted

on the

carriage

assembly.

Printing

occurs

only when

the

carriage is

moved

from left

to

right.

When the

printer is

turned

on

and after

printing

each line,

the

print

head

is

moved to

the left

side

of the

printer

mechanism.

The

carriage

assembly

is

driven

by a

reversible

dc

motor

mounted

on the assembly.

When

a

print

command

(CR) is

received

the

motor is

energized,

the

carriage assembly

is

moved in

the

forward

direction,

and the

contents

of

the

input

buffer

is

printed.

As

the

carriage assembly

moves,

an

encoder

wheel (which

has

magnets

imbedded

in it)

is

rotated.

The

column

sensor

(Hall

effect

device)

senses

when

each

of the

magnets

moves

past

it

and generates

column sense

signals

which

are

used to

synchronize

the

print

head

solenoids.

Upon completion

of

printing

a

line of

data,

the polarity

of the

dc voltage

applied to

the carriage

drive

motor

is

reversed

and the

carriage

assembly

is

moved to the left

side

of

the

printer.

1-4

Figure

1-2.

PICTORIAL

DIAGRAM

1-5

Paper is

automatically moved up one

line after

each line is printed

or whenever a

line feed

(LF) control code is sent by the host

device.

When

a

line

feed

is to be

executed, the

line feed solenoid is momentarily energized

which

causes the paper feed roller

to move the paper one line. The automatic

line

feed

function may be disabled. However, if this function is

disabled,

the

host device must transmit at least one LF command prior

to

sending

a

print

command

(CR)

or a

full line of character data or overprinting will

occur.

Line feed (LF) commands may

be

intermixed

with input character data

and multiple

line feed commands may be sent by

the host device. A special

line feed buffer

is provided

which

can

store up

to 255 pending line feeds.

The

initial

line feed received causes

an

immediate

advance

of

one

line.

Because

of the

time required

to execute

a

line

feed is relatively

long

(160

milliseconds) with

respect

to the input

data rate

(9300

characters

per

second)

subsequent line feeds

are stored

as

a count

in

the

line

feed

buffer.

All

line

feeds are executed prior to printing

the line of data.

The

printer uses

a

Mobius strip

ribbon configuration

which allows

printing

on the upper and lower portions

of the ribbon on alternate passes

of

the ribbon thereby increasing ribbon life. The

ribbon drive motor

(ac)

is

energized at

all

times except when the print

head is at the left-most position.

This insures

proper movement of the ribbon through the ribbon

path and compen-

sates for

the movement of the print head in

both forward

and reverse directions.

1-6

1.5

SPECIFICATIONS

1-1.

The

specifications

for

the Line

Printer

II

are contained

in Table

Table

1-1.

Specifications

Ribbon

(12

per

box)

Paper

Printing Speed

Characters Per

Line

Print Width

Character

Structure

Line Feed

Buffer

Line

Feed

Repeat

Rate

Vertical

Spacing

Horizontal

Spacing

Parallel Data

Input

Connector

Parallel

Interface

Cables

Code

Character

Set

Input

Character

Format

Input

Data

Rate

Input

Voltage/Frequency

Power

Requirements

Size

Weight

15-yard zip

pack Mobius

strip

Cut

Sheets

(8

1/2-inches

wide)

Rolls

(3

1/2-inches

to 8

1/2-inches

wide

x 5-inches

diameter

with

1-inch

Core) , 2

ply

Fanfold

(9-inches

pin-to-pin)

, 3 ply

28

lines

per minute

(1pm) at

80 characters

per line

(cpl) or

74

1pm at 20

cpl left

justified

80 maximum

@

10 cpi/132

maximum

@

16.7 cpi

8

inches

maximum

(204 mm)

7x7 Dot

Matrix

Capacity

for

255

pending

line

feeds.

9 linefeeds/second

6 lines

per

inch

10

characters

per inch/16.7

characters

per inch

40-pin

PC

edge

connector

Maximum

length:

10

feet

Type:

Twisted

pair

Gauge:

26 AWG

Standard

ASCI

1-2

Dip

switch

selectable

for

U.S.A.,

France,

United

Kingdom,

Germany,

Italy

and

Sweden/Finland

8 parallel

data

bits.

Up to

9300

characters/

second.

120 Vac

+_10%

60

Hz

100 Watts

14 1/2-inches

W x

11

-inches

D

x

5-inches H;

(368 mm)

x

(279 mm)

x

(127 mm)

12 pounds

(5.4 Kg)

1-7

SECTION

2

INSTALLATION

2.1

INSPECTION

Visually

inspect the

printer for

signs

of damage

received

during

shipment.

Notify the

common carrier

immediately

of any

discrepancies.

NOTE

Any

attempt to operate

a damaged

printer

voids

the warranty

and may cause

further

damage.

2.2 INTERFACE

INFORMATION

2.2.1 PRINTER

INTERFACE

CONNECTOR

A 40-pin

printed

circuit edge-card

connector

located

at

the left

rear

of

the

printer

provides

the means for

connecting

the

printer

to an input

device. The

physical

and electrical

characteristics,

pin

orientation,

and

connector

pin-outs

of

the printer

interface

connector

are shown

below.

COVER OUTLINE

K

15°

TYP

0.02x45°

CHAMFER

PIN 40

I

f

0.75

0.035

KEY

BETWEEN

PINS

36 &

38

PINS

ON

.100

M-s

0.88

Figure 2-1.

TOP

VIEW OF

PRINTER

INTERFACE

CONNECTOR

2-1

2.2.2 INTERFACE

CONNECTOR PIN-OUTS

Table

2-1

shows

interface

connector

pin

numbers and

the input

and

output

signals at

each pin.

Table

2-1

.

Printer

Interface

Connector

Pin-Outs

PIN

SIGNAL

PIN

1

DATA STROBE

2

3

DATA

BIT

1

4

5

DATA

BIT

2

6

7

DATA

BIT

3

8

9

DATA BIT

4

10

11 DATA

BIT

5

12

13 DATA BIT

6

14

15

DATA

BIT

7

16

17 DATA

BIT

8

18

19

ACKNOWLEDGE (ACK)

20

21

BUSY

22

23 ALWAYS

LOGIC

(GROUND)

24

25

ALWAYS

LOGIC

1 (+5V)

26

27

SIGNAL

GROUND

28

29

NOT

USED

30

31

SIGNAL

GROUND

32

33 CHASSIS

GROUND

34

35

+5V

SIGNAL

(P.S.

ON)

36

37 NOT

USED

38

39 NOT

USED

40

SIGNAL

TWISTED

PAIR

GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR

GROUND

TWISTED

PAIR GROUND

TWISTED

PAIR GROUND

TWISTED

PAIR

GROUND

NOT

USED

ALWAYS

LOGIC

1

GROUND

PIN

32 JUMPERED

TO PIN

34

FOR

SENSING PRINTER

CONNECTED

DEMAND
NOT

USED

NOT

USED

(DATA STROBE)

(DATA BIT

1)

(DATA BIT

2)

(DATA BIT

3)

(DATA BIT

4)

(DATA

BIT

5)

(DATA

BIT

6)

(DATA BIT

7)

(

DATA

BIT

8)

(ACKNOWLEDGE)

(BUSY)

(DEMAND)

2.2.3 INTERFACE

DRIVERS AND

RECEIVERS

Figure

2-2

illustrates the

requirement

for

drivers

and

receivers

used

in the

interface.

All

levels

are TTL

compatible.

LO

=

0.4 volts

HI

=

2.4

volts

@ 400ua

@ 1 6ma

O

<

LO

=

0.4 volts

HI

=

2.4

volts

@

7ma

@

O.Oma

IK

t>

DRIVER

RECEIVER

00844

All

input/output

signals

are

TTL

compatible.

Figure 2-2.

INTERFACE

DRIVERS

AND

RECEIVERS

2-2

2.2.4 INTERFACE COMMUNICATION

AND TIMING

The

paragraphs

below

describe the interface

communication

signals.

Figure

2-3

illustrates the interface timing.

Data Strobe (Host Generated)

The

data strobe (DATA STROBE) signal is

a negative

going

pulse which

is used

to transfer the incoming data from the host

into the

electronic

circuitry of the

printer. The pulse duration

must be a minimum

of one micro-

second. The

relationship of the leading

and trailing

edges of the DATA STROBE

signal with the

leading and trailing edges of the

input data

signals must be

as shown in the

interface timing diagram

(See Figure 2-3)

Data Lines (Host

Generated)

The eight input data lines

provide the

means to transfer

bits 1

through

8 of the ASCII character

data and control

code data. The

presence

of logic

1 bits is indicated

by positive going signals.

Acknowledge

(Printer Generated)

The acknowledge (ACK) signal is

a negative

going signal

which indi-

cates that

the printer has

processed the latest

data transferred from

the

host

.

No

new data

can

be sent

to the

printer until

the leading

edge of

the

ACK

pulse has

occurred. If the

printer receives

a carriage return

(CR)

control code, or

if

the printer

print buffer

or line feed buffer

becomes full,

the acknowledge pulse will

not occur until

after the

line has been

printed

or

until the

line feed buffer

becomes only

partially full.

Busy

(Printer Generated)

The

BUSY

signal is

a positive going signal

which

indicates

the time

when the printer

cannot accept

new

data. The

BUSY

signal

goes positive on the

trailing

edge of

every data strobe pulse and

remains high

until the

leading

edge of the

acknowledge

pulse. No new data

can be

sent to the

printer while

the BUSY signal

is

high.

Demand

(Printer

Generated)

The DEMAND signal is

the inverse

of the BUSY

signal.

When high

(positive)

,

the DEMAND signal

indicates that

the

printer

can accept

data.

+5V

Signal

(Printer

Generated)

The

+5V signal (I/O Connector, Pin

35)

indicates

that the

+5V power

supply is

operating in

the printer. The

+5V signal

is intended

to

be

used for

signal

purposes only

and

it

must

not be

used

to provide

power

to external

equipment

2-3

DATA BIT

1-8

J.

nin

I

min

[

I

I

«1us

min

>

\

-

1

us

,Xl

us

»

mm

|

min

1

h

lus

min

00840

i

(

DATA STROBE

*100us

11

HI

±5us

<(

1

ACK

! r

50ns

max

1

5us

>u

'

±0.! s

*"

BUSY

50ns

J

max

"

—

\)

—

H

-•-50ns

DEMAND

*

100

usee

is for

data

reception and

line

feeds

that

do not fill

the line feed

buffer.

For

line feeds

that

fill

the

buffer,

the time

is 1

1

msec

+10%, -0%.

For

carriage

return

codes,

the maximum

time is

2.6 seconds.

In

approximately

10%

of the

data

transfer

cycles

(strobe

to ACK cycles)

a micro-

processor

interupt

occurs

which

extends

the

busy

time from

a

nominal

1 00 usee

to approximately

200

usee.

Figure 2-3.

INTERFACE

TIMING

2.2.5 HOST-GENERATED

CONTROL

CODES

Control

code data is

sent

to the

printer

along

with

character

code

data via

the input

data lines.

Control

codes

are sent

as

data,

but

are

interpreted

as instructions

by

the

printer.

A

summary

of

the

control

codes

and

control

code

sequences

recognized by

the

printer

is

shown

below.

Each

of

the control

codes

is described

in

detail

in

the

following

paragraphs.

Function

Full

Line

Feed

Forward

Print

Command

Start

Elongated

Characters

Stop

Elongated

Characters

Select

10 cpi

Character

Density

Select

16.7

cpi

Character

Density

Mnemonic

Decimal

Octal

Code

Hex

Code

LF

10

012

0A

CR

13

015

0D

ESC

SO

27,14

033,016

1B,0E

ESC,

SI

27,15

033,017

1B,0F

ESC,

DC3

27,19

033,023

1B,13

ESC, DC4

27,20

033,024

1B,14

Line

Feed

(LF)

Code

Each

line

feed

(LF)

code

received

by

the

printer

causes

the

paper

to

be

advanced

one line.

Line feed

codes

are

received

at

the

same

rate

as

character

data

(up

to

9300 characters

per

second.)

When

multiple

line

feed

codes

are

sent

to the

printer,

the

initial

line

feed

code is

acted

upon

immediately

and

the

additional

line

feed

codes

are

stored

in

the

line

feed

buffer

as

a

count.

If

more

than

255 lines

feeds

are

received

the

printer

will

go BUSY,

and

no

more

data

can

be sent

to

the

printer

until

pending

line

feeds

have

been

processed

and

the

line feed

buffer

is

partially

full.

Line

feed

codes

and

character

data

can be

intermixed,

however

all line

feeds

in

the

buffer

will

be

processed

before

the

next

line

is

printed.

2-4

Carriage

Return

(CR)

Code

The

carriage

return (CR)

code serves

as

a print

command to

the

printer.

Data is

received

by the

printer

and stored

in the

print

buffer

until

a

CR

code

is

received.

Upon receipt

of

a

CR

code,

the

contents of

the

print

buffer

are

printed.

If

the print

buffer

is

filled,

a

CR code

is

generated

by the

printer

and

the line

is

printed.

The print

head

is

returned

to the

left

margin

after

the

content

of

the

print

buffer is

printed.

ESC, SO;

ESC,

SI Code

Sequence

and Data

Bit

8 Control

The ESC,

SO

code

sequence

(or bit

8

logically

high)

initiates

printing

of

elongated

characters

(doublewidth

characters.)

The ESC,

SO code

sequence

may be sent

to

the printer

at any

time

during

the

transmission

of

a line of

character

data

(up to

40 characters.)

Reception

of

an ESC

SI code

sequence

(or

bit

8

logically

low) causes

all data

following

the

code

sequence

to be

printed

normal

size.

The

end of a

print

line

terminates

printing

of

elongated

characters.

The

next

line of data

will

be

printed

as standard-width

characters

unless

an ESC,

SO

code

sequence is

received

during

the

transmission

of the

character

data

for that

line.

ESC,

PCI;

ESC,

DC3

Code

Sequence

The

primary

character

density is

10

cpi,

selected

by the

printer

logic during

initialization,

or by ESC,

DC3.

The ESC,

DC4

code

sequence

selects

the

16.7 cpi

character density.

The

print

buffer

is

set

to 80 char-

acters

for

10 cpi and

132

characters for

16.7

cpi.

The

16.7

cpi

character

density

is

deselected

by

sending

an

ESC,

DC3

code

sequence

or

at the

end of

a

print

line.

2.2.6 ASCII

CODE CHARTS

Figures 2-4

through

2-6

are the

ASCII

code

charts

showing

the

96

ASCII

characters

for

the six

different

character

sets,

the

codes for

the

various

characters,

and the

control

codes

recognized

by the

printer.

2-5

-%.

% \ %

\

1

°o

1

°1

1

io

\

k\

b

4

b

3

t

b

2

t

^Column

1 2

3

4 5

6

7

NUL

DLE

Space

I? P

4-

p

1

1 SOH

DC1

1

1

A

Q

a

a

1

2

STX

DC2 2

B

R

h

r

1 1

3

ETX

DC3 *

3

C

S

c s

1

4

EOT

DC4 * 4 D

T

d

t

1 1

5

ENQ

NAK

•/.

5

E

U

e

u

1 1 6 ACK SYN

8

6

F

V f

V

1

1 1 7

BEL

ETB

1

7 G

W

G

u

1

8

BS

CAN

<

8

H

X

h

y^

1 1

9

HT EM

)

9

I

Y

i

y

1 1 10(A)

LF SUB

*

:

J

Z

J

Z

1

1 1

11

(B)

VT

ESC

+

?

K t

k

<

1

1

12(C)

FF

FS

r

L.

\

1 1

1 1

1 13(D)

CR GS

-

=

H

3

M >

1 1 1

14(E) SO RS

.

>

N

*

|-|

-»

1

1 1 1

15(F)

SI

US /

?

<-

O

CONTROL

CODES

A.

U.S.A.

STANDARD

~%.

On

°0

°°1

%

\ \

\

1

1

\

kA

b

4

t

b

3

t

b

2

t

^\Column

1

2

3 4 5

6

7

NUL DLE

Space

n

*

P

-

p

1

1

SOH

DC1

1

i

A

Q a

Q

1

2

STX DC2

2

B

R

h

r

1 1

3

ETX DC3

f.

3 C

S

c

s

1

4

EOT

DC4 *

">

D

T

d

t

1

1

5

ENQ

NAK

•/.

5

E

U

e

u

1 1 6

ACK

SYN X b

F

V f

V

1 1 1 7 BEL

ETB

'

7 G

W

G

w

1

8

BS

CAN

(

8

H

X

h

1

1

9

HT

EM

)

9

I

Y

i

y

1 1

10

(A)

LF

SUB

*

:

J

7.

J

z

1

1 1 11 (B)

VT

ESC

+

t

K

°

k

£

1

1

12(C)

FF

FS

f

L

C

1 d

1 1

1

13(D)

CR

GS

-

=

M

5

M

£

1 1 1 14(E) SO RS

•

N

A

n

1

1

1 1

15(F)

SI

US /

->

o

CONTROL

CODES

B. FRANCE

STANDARD

Figure

2-4.

ASCII

CODE

CHART

2-6

"!i.

On

°0

°°1

%

\

\

1

o,

1

io

\

k\

b

4

+

b

3

t

b

2

t

i

^\Column

1 2

3

4 5

6

7

NUL

DLE

Space

e

P + p

1

1

SOH DC1

!

1

A

Q

3

a

1

2

STX DC2 2

E:

R

h

r

1 1

3

ETX

DC3

£

3

C

S

c s

1

4

EOT

DC4

*

4

D

T

d

t

1 1

5

ENQ

NAK

%

5

E

U

e

u

1

1 6 ACK SYN X

6

F

V f

V

1 1 1 7

BEL

ETB

7

G

w

G

u

1

8

BS

CAN ( 8

H

X

h

yt

1 1

9

HT EM

)

9

I

Y

i

H

1

1 10(A)

LF SUB

X

:

J

7 J

Z

1 1

1

11 (B)

VT

ESC

+

*

K r

k {

1 1

12(C)

FF FS

r

L \

1

1

1

1 1

13(D)

CR GS

-

=

M

] M >

1 1 1 14(E) SO RS

•

N *

n

-»

1 1

1 1

15(F)

SI

US /

?

_

o

CONTROL

CODES

STANDARD

C.

UNITED KINGDOM

^7k

^5

"!!U

On

°0

\ %

\

1

°o

S

1

io

\

kA

b

4

b

3

t

b

2

+

^\Column

Row^-v^

1

2

3

4 5

6

7

NUL

DLE

Space

S

P

^

p

1

1 SOH

DC1

|

1

A

3

o

1

2

STX

DC2 2

B

R

h

r

1 1

3

ETX

DC3

*

3

C

S

c

s

1 4

EOT

DC4

$

1 D

T

d

t

1 1

5

ENQ

NAK

7.

cr

E

U

e

i_i

1

1 6 ACK SYN 8

6

F

V f

V

1

1

1

7

BEL ETB

'

7 C

w

6

w

1

8

BS

CAN < 8

H

X

h

::

1 1

9

HT EM

)

9

I

Y

i

y

1 1 10(A)

LF

SUB

%

:

J

7

J

z

1 1

1

11

(B)

VT

ESC

+

i

K

S

k

3

1

1

12(C)

FF FS

t

L

1 6

1 1 1

13(D)

CR GS

-

=

M

M

U

1 1 1

14(E) SO RS

•

N

A

n

ft

1 1

1

1

15(F)

SI US /

?

...

o

CONTROL

CODES

STANDARD

D. GERMANY

Figure

2-5.

ASCII CODE CHART

2-7

\t>5

"!^_

On

°0

o

0l %

\

\

\

\ \

kA

b

4

b

3

t

b

2

b

1

*

^^Column

Row^\

1 2

3 4 5

6

7

NUL DLE

Space

S

P

6

p

1

1 SOH

DC1

1

1

A

Q

3

a

1

2

STX

DC2 2

E5

R

h

r

1 1

3

ETX DC3

£

3 C

B

c s

1

4

EOT

DC4

*

4

D

T

d

t

1

1 5

ENQ

NAK

y.

5 E

U

e

u

1 1

6 ACK SYN 8

6

F

V

f

V

1 1 1

7

BEL

ETB

i

7 G

w

G

w

1

8

BS

CAN

< 8 H

X

h

;:

1

1

9

HT

EM

)

9

I

Y

i

y

1 1

10 (A)

LF

SUB

X

:

J

Z

J

z

1

1 1 11 (B) VT

ESC

+

J

K

o

k *

1 1

12(C)

FF FS

t

L

£

1

<b

1 1

1

13(D)

CR GS

-

=

M

1 M

&

1

1

1 14(E)

SO RS

•

N

A

n

i

1

1 1

1

15(F)

SI

US /

? -

o

CONTROL

CODES

E.

ITALY

STANDARD

^b

~!^_

°0

°°1

°io

'1

1

°o

s %

\

k\

b

4

b

3

b

2

t

b

1

^\Column

1 2

3 4 5

6

7

NUL DLE

Space

6 P

&

p

1

1

SOH DC1

|

1

A

Q 3

a

1

2

STX DC2

2

B

R

b

r

1

1

3

ETX

DC3

* 3 C

S

c

5

1

4

EOT

DC4 X 4

D

T

d

t

1

1

5

ENQ

NAK

Z

5

E

U

e

u

1 1 6

ACK

SYN « 6

F

V f

V

1 1 1

7

BEL

ETB

'

7 G

W

G

u

1

8

BS

CAN ( 8 H

X

h

X

1

1

9

HT

EM

)

9

I

Y

i

H

1 1

10

(A)

LF

SUB

X

:

J

Z

j

z

1

1 1 11 (B)

VT

ESC

+

*

K

A

k 3

1 1

12(C)

FF FS

r

< L.

1 6

1 1

1

13(D)

CR GS

-

=

M

A n

3

1 1 1 14(E) SO RS

•

N

u n

u

1

1 1 1 15(F)

SI

US /

7

_

o

CONTROL

CODES

STANDARD

F. SWEDEN/FINLAND

Figure

2-6.

ASCII

CODE CHART

2-8

2.3

AUTO

LINE FEED

ENABLE/DISABLE

The

Automatic Line

Feed (ALF)

function

is

controlled

by

a DIP

switch

(Section

1

of

SW3) on the logic P.C.B.

(Refer

to

Figure

2-7)

. The

printer is

shipped

from the factory

with

this switch

in

the ON

position

(Auto

Line Feed

Enabled)

.

If

the auto line feed

is to

be

disabled,

set the

switch

in the

OFF

position.

2.4 CHARACTER

SET SELECTION

The unit

can print

character

sets

of six

countries:

U.S.A.,

France,

United

Kingdom,

Germany,

Italy

and

Sweden/Finland.

The table

in

Figure 2-7

shows

the settings

of Sections

2,

3 and 4 of

SW3

for the

various

character sets.

To

select the desired

character

set, place

the

POWER

switch

in

the OFF

position;

remove the top

cover

and

select the

character

set

per

Figure 2-7.

Replace

the

top cover and

restore

power. NOTE:

The

unit is

shipped

from

the factory

configured

for

the

U.S.A.

character

set.

NOTE:

POSITION

1 ON

SW3

IS SHOWN

IN

THE

AUTO

LINE FEED

ON

POSITION

CHARACTER

SET

POS

ON SW3

2 3

4

USA

FRANCE

UK

GERMANY

ITALY

SWED/FIN

ON

ON

ON

OFF

ON

ON

ON

OFF

ON

OFF

OFF

ON

ON

ON

OFF

OFF

ON

OFF

Figure

2-7.

SETTING

AUTO

LINE

FEED AND

CHARACTER

SET

SWITCHES

2-9

SECTION

3

THEORY OP OPERATION

3.1 BASIC DESCRIPTION

Figure

3-1

is a basic block diagram

of the Line Printer

II. All

logic,

control, drive, and power

supply

circuits

are contained on one

printed

circuit

board within the printer. The print

head is

mounted on

a

carriage

assembly driven by a dc motor.

Printing is

performed in the forward direction

only

(left

to

right)

,

printing up to seven

dots

per column.

The

paper drive

roller is driven by a line feed solenoid

which advances

paper

1/6

inch each

time the

line feed solenoid

is

actuated. The

ribbon drive

motor moves ribbon

past

the print

head at all times except when

the carriage assembly

actuates

the

sensor at the leftmost

carriage position.

The power supply

provides +5V

regulated,

+5V

EXT SENSE

for host device

sense,

+12V regulated for motor

drive, +17 for

solenoid drive, and +24 VAC

for the

ribbon drive motor.

The

host

device transmits 8-bit

parallel

(ASCII) data signals

and a

data strobe

signal to the printer

logic. Control of

the transfer of data is

achieved

using

the busy, demand,

and acknowledge

signals generated

by the

printer logic.

HOST

DEVICE

PRINTED CIRCUIT BOARD

8

-BIT DATA (Note

1)

I

DATA STROBE

^

BUSY

DEMAND

ACKNOWLEDGE

•

CPU

•MEMORY

•CONTROL

LOGIC

•

DRIVE

CIRCUITS

+5V EXT SENSE

I

I

Figure

3-1.

I

+5V

POWER

SUPPLY

IPRINTER

I MECHANICS

I

00837

SOLENOID

DRIVE

FWD/REV

LINE FEED

24 VAC

+12V
+17V

^

7

-PIN

PRINT

HEAD

CARRIAGE

DRIVE

MOTOR

(DC)

LINE

FEED

SOLENOID

RIBBON

DRIVE

MOTOR

(AC)

LINE PRINTER

II

BASIC

BLOCK

DIAGRAM

-J

3-1

The

printer accepts

and stores

input

character

data in

an input

buffer

until

either the buffer

is filled or

a

carriage

return

(CR)

control

code is received.

If the

buffer is filled

or

a CR

code is

received,

the

content

of the input

buffer

is printed.

Printing

of

the

characters

is

achieved

by

energizing solenoids

in the

print head

which

drive

circular

pins

against the ribbon,

paper, and platen as the

print

head is

moved by

the

carriage

drive motor forming

the characters

in

a 7x7

dot-matrix

pattern.

Upon

completion

of printing

the print

head is

moved

to

the left

margin

and

the

paper is

advanced

one line

by

energizing

the line

feed

solenoid.

Line

feed (LF)

control

codes

received

by

the

printer

control

paper

movement.

Each

line feed

code received

causes

the

paper

to be

advanced

one

line.

The

printer has

a

special

line

feed

buffer,

separate from

the

input

buffer,

which

can store

up to

255

line

feed

commands.

LF

control

codes

are

received

at the

same data

transfer rate

as

character

data

(up

to 9300

char-

acters

per

second)

.

The initial

LF

code causes

an immediate

advance

of one

line.

Additional

line feed

codes

received

are

stored

as

a count in

the

line

feed

buffer.

Line

feed

codes and

character

data

sent

to the

printer

may be

intermixed,

however,

all line

feeds

received

are

performed

before

printing

the

next

line

of data.

Automatic

line

feed

upon completion

of

printing

each line

may be

disabled

by

setting

Section

1

of DIP

switch

3 on

the

printer

logic

printer

circuit

board

to the OFF

position.

If this

function

is

disabled,

the first

line of

data will

be printed

when a

CR control

code is

received or

a buffer

full

condition

occurs.

After printing

the first

line of

data,

the print

head

is

returned

to

the left

margin

and the

paper

is not

advanced.

The second

line

(and

subsequent

lines)

of data

must have

at

least

one LF

control

code

preceed

each CR control

code

or buffer full

condition,

or

overprinting

will occur.

Line

feed

codes

may be used

for

limited

paper handling

functions.

Each

line

feed

code moves the

paper one-sixth

of

an inch.

Thus,

for

example,

if it

is desired

to move the

paper

12 inches,

72

line feed

codes

are required

before

a

CR

control

code is

sent.

On power-up

or

reset, the

printer

is preset

to

the 10

cpi

character

density.

To

select the

condensed

16.7 cpi

character

density,

an ESC,

DC4

code

sequence

is

sent to the

printer. The

input

buffer is

set

a 80

characters,

buffer

full,

for

10 cpi

and 132 characters,

buffer full,

for

16.7

cpi.

The

ESC,

DC4

code

sequence sent

within

a

line

of

data is

ignored.

The 16.7

cpi

condensed print

is

deselected

by sending

an ESC,

DC3

code

sequence

or

at the

end of

a print

line.

The

two

character

densities,

10 and 16.7

cpi

may be

elongated

anywhere

in the line.

Elongated

characters

are

double

width

characters

formed

by

printing

each

column of

dots within

each

character

twice.

Spaces

between

characters

are

also twice

as wide. This

effectively

halves the

number

of

characters

per inch

(cpi)

.

Figure

3-2

shows

the

normal

and

elongated

character

styles.

Elongated

characters

are initiated

by

using

the escape

code ESC,

SO

code

sequence

(or data bit

8 logically

high)

and

terminated

by the

escape

code

ESC, SI

code

sequence

(or data bit

8 logically

low) . Elongated

characters

are

automatically

terminated

at

the end of

a line.

Reception

of

an ESC

SO code

sequence

causes

all data following

the

code

sequence

to be

printed

elongated.

Control

code

sequence ESC,

SI causes

all data

following

the

code

sequence to

be printed normal

size.

Elongated

characters

may

be initiated

and terminated

any

number

of times within

a

line.

The

end

of a print

line

terminates

printing

of

elongated

characters,

and

unless

elongated

characters

are initiated

by

the ESC,

SO

code sequence

preceeding the

data

for the

next

line,

the

characters

in the

next line

will be

printed

normal

size.

3-2

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NORMAL

CHARACTERS

(10 cpi)

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ELONGATED

CHARACTERS

(10 cpi)

Figure

3-2.

LINE

PRINTER

II

CHARACTER

STYLES

3-3

Figure

3-3

shows

the printer

interf

ace

timing.

Each

set

of data bits

(1-8) sent to

the

printer is strobed

by the

DATA STROBE signal sent to

the

printer by

the host

device.

Within 50

nanoseconds

following the trailing edge

of the

DATA

STROBE signal a

BUSY signal

is generated by the

printer which is

sent to

the host

device.

The

BUSY signal informs the

host device that

the

printer

is

processing the

input

data and that no

additional data from

the host

device

will

be

accepted

by the

printer. After completion of processing the

input data an

acknowledge

(ACK)

signal is

sent to the

host device

indicating

that the data sent

by the host

device has been accepted and

processed.

Within

50

nanoseconds

following the leading edge of

the ACK signal the BUSY

signal is

terminated indicating that

the printer is again ready to accept

additional

input data.

A

DEMAND

signal is also generated by the printer and

is available

to the host device. The

DEMAND

signal

is the inverse of the BUSY

signal and

when present (positive)

indicates that the printer is not busy and

is ready to

accept data.

DATA BIT

1-8

—

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4-

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us

4-

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min

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mm

DATA

STROBE

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min~min

|

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00840

.

*100us_)

V-

±5us

^

r

-ih

ACK

BUSY

50ns

max

^K

50ns

ma

is

. 1

5us

'

+0.5us

H~

50ns

DEMAND

HV

*

100 usee is

for

data

reception

and line feeds that

do not fill the

line feed buffer. For line feeds

that

fill

the buffer,

the time is 110 msec +10%,

-0%.

For carriage

return codes, the maximum time is

2.6 seconds.

In approximately 10% of

the

data

transfer

cycles

(strobe to

ACK cycles)

a

micro-

processor interupt

occurs which extends

the

busy

time from a

nominal 100 usee

to

approximately

200 usee.

Figure

3-3.

INTERFACE TIMING

The

time

be

tween

the trailing edge of the DATA STROBE

signal and the

leading

edge of the

ACK signal

(data transfer

cycle

time) varies with the

functions

to be

performed by the printer. For

normal

data inputs

and

LF

control

codes

which do not

fill the

line

feed buffer,

the duration is nominally

160 microseconds. For

LF control codes which fill

the line feed buffer, the

maximum time

is 110

milliseconds

+10,

-0%.

The maximum time

for carriage

return codes is 2.6

seconds. In approximately 10% of the

normal data

transfer

cycles

a microprocessor

interrupt occurs which extends the time

from a

nominal

100 microseconds

to

approximately 200 microseconds.

Figure

3-4

shows the acknowledge

timing

on power-up.

When

power

is

initially

turned on, approximately

20 milliseconds is required for internal

voltages

(+5V) to

stabilize. Within 30 milliseconds after

power

is turned on

the BUSY

signal is generated and

the printer remains in the BUSY condition for

the next

170

milliseconds.

The BUSY signal is then terminated

and the

printer

generates the first

acknowledge

pulse indicating that the

printer is no longer

BUSY,

is on line, and

i

s

rea

dy to accept data.

Data should

not be sent to the

printer until

the

first

ACK signal is

sent to

the host

device.

3-4

POWER ON

SWITCH

ON

OFF

+5V

LINE

BUSY

LINE

ACK

INDETERMINATE

CONDITION

FIRST

ACK

PULSE

(PRINTER

ON

LINE)

00839

Figure

3-4.

ACKNOWLEDGE

TIMING

ON POWER-UP

The POWER

ON/OFF

switch

controls

the

application

of

primary

power

to

the

printer.

When

power is

turned

on,

an LED

visible

through

the

paper

exit

slot

indicates

that

the

+5 volts is

active.

The

ONLINE/OFFLINE

switch

controls

the

printer

modes of

operation.

When

placed

in

the

ON

position,

the

printer

is

placed

in

a local mode

of

operation,

a

BUSY

signal

is

sent to

the

host

device,

the

printer

electronics

are

reset,

and the

input

buffer

is

cleared.

When

placed in

the OFF

position,

the

printer

electronics

are

reset,

the

print

head

is

returned

to the left

margin,

and the

BUSY

signal

is

discontinued

allowing

data to

be

sent by

the host

device.

If

the

switch

is

placed

in the

ON

position

when

the

printer

is processing

a line

of

data,

the

printer

will

complete

printing

the

line of

data,

return the

print

head

to the

left

margin,

then

reset

the

printer

electronics

and

clear

the

input

buffer.

If

the

printer

is

performing

multiple

line

feeds

at the

time

when

the

switch

is

placed in the

ON

position,

the

line

feed

operation

currently

being

performed

will

be completed

and

the

remaining

line

feeds

will be

processed

when

the

printer

is

returned

to

the

on-line

mode.

The

ONLINE/OFFLINE

switch

should

be

placed

in

the OFFLINE

position

when

turning

power

to the

printer

on

or off

as

extraneous

acknowledge

(ACK)

signals

can

occur

during

the

periods

when

power is

initially

turned

on

or

off.

CAUTION

Actuation

of the

ONLINE/OFFLINE

switch

results

in loss

of

data

contained

in

the

input

buffer.

3-5