Alphacom SPRINTER 40 User manual
INSTRUCTION
MANUAL
SPRINTER 40
TABLE OF CONTENTS
Intduction
9
Character printing
The they of thermal printing Normal characters
2
Description of printer
Carriage ret
Figure 1 Top, boom, side view of printer with Linefeed
details pointed o t Multi linefeed
3
General description of printer operation
Right justify
Power req irements Speed ntrol
Paper requirements Graphics mode
4
Loading the paper (ll and nld) Auto wraparound
Figure 2 Steps in loading paper Fanld paper
Running in test mode
13
Gra hics printing
5
Interng the Sprinter (and limitations of
The graphics matrix orientation
5 volt power)
Software strategy
6
Parael Interng
Speed and timing
Desiption of the parallel interce Graphics browno t
Critical timing nsiderations
14
Serving the printer
Use of the BUSY Signal Removing and replacing printer mechanism
8
Serial Interng
Removing paper jams
Description of RS-232 Lubrication
Critical timing considerations Replacing thermal heads
Use of the BUSY signal Dot alignment ntrol
8
Interng to spefic computers
15
Serving the controer
General purpose cable Opening and closing case set
Fu RS-232 cable Replacing blown fuse
Pasve RS-232 cae Replacing the VLSI ntroller
TRS-80 Adjusting dot timing duration
APPLE cable and interce card Other maintenance not remmended
PET IEE-488 cle 16
Parts Diagram (exploded view)
ATARI 400,800 17
Parts st
MAEL lntellivision 19
Sprinter schematic
20
Appendix
INTRODUCTION
Congratulations on your purchase of the
SPRINT HIGH SPE TH MAL NE PRINT.
You now own one of the most reliable printer
units ever introduced r use with personal m
puters, with a printing mechanism backed by
field experience with more than a million similar
units.
The SPRINT uses true line-printing
technology, in which 40 characters are multa
neously produced as a 5 x 8 character nt pat
te with a matrix raster of 7 x 10dots. The dot
matrices are contiguous acss the printed page
and make it possible r the printer to be used as
a ploer as well as a character printer.
Lines of dots are produced by an oscillating
motion of two thermal heads, each of which
simultaneously produces 20 dots on thermo
graphic paper stock. Since the lightweight heads
move only a action of an inch, they are able to
reverse direction very quickly, with high energy
eiciency. Their design permits the use of a low
voltage DC motor with low power nsumption,
which is easily ntlled r starting and
stoppin
During the printing operation, as the print
heads reverse their direction of travel, the paper
is advanced one dot position by a gear cam d
ven by the DC motor. The unique degn simplic
ity is the undation upon which the reliability
and perrmance of the SPRINT is built
The thermal heads used in the SPRINT
PRINT are made om ceramic-like substrate
on which are built 20 printing dot sites. The sites
are built up above the substrate to enhance n
tact with the thermal paper and to reduce fc
tional drag. Dot impressions are eated by
selectively heating the thermal head dot sites,
which in tu transfer their heat to a point on the
paper with which they are in ntact At the
point of ntact, a special ating on the paper
will change lor and produce a vible impres
sion. The SPRINTER is capable of creating more
than 10,000 dot impressions every second!
side
l
0
r
DESCRIPTION
The SPRINT is enosed in a tough ABS
molded case which i extremely resistant to im
pact damage. The transparent paper ver is
made om durable acrylic material imilar to
that used in airaft wind hields. The fine mae
case finish requires no special care and should be
cleaned, if necessary, by wiping with a slightly
damp oth. Wax cleaners should not be used.
The paper cover may be cleaned with any good
quality aylic cleaner which does not ntain
abrasives.
The acmpanying Figure 1 illu trates the
major mponents of the SPRINT.
The paper cover
(1)
is hinged to permit a roll
of paper to be loaded and positioned.
The paper relea e lever (2) i provided to
simplify the threading of a new paper roll into
the printing mechanism.
The exteal power stch (3) and the
paper advance switch (4) are nveniently
provided on the ont suace of the uni
Ventilation lots are provided through the
top and bottom vers r nvection oling
of inteal mponents; the SPRINT should
always be placed on a hard surce o that the
oling vent are not obstructed in any way.
All nnections to the SPRINT are made
through an edge-type nnector at the rear of
the uni
Access to the SPRINT mponents may
be gained by first removing the rubber feet
under the lower case, and then removing the
recessed sews which secure the top and
boom ca e sections.
2
top boom
POWER REQUIREMENTS
The label on the underside of the lower
case will indicate the correct power supply.
Ser ous damage may result om aempting
to operate om an inrrect power source. Field
mod fication to nvert a un t om one power
source to another is not remmended due to
possible safety hazards.
The energy-eic ent SPRINT nsumes
only about 3 was of power and is silent when
not pr nting. The low power dra n makes it n
venient to power up with the host mputer.
When pr nting beg ns, power consumption
r ses n pportion to the pr nting speed and to
the number of dots being printed. The power
nsumption, when printing full character lines
at 4 l nes per send, s approximately 30 watts.
As a rem nder to switch the printer o
when not in use, the power switch is located on
the upper ver, and indicates clearly the
ON
or
OFF
condit on by its position.
In add tion to pv ding its own power, the
SPRINT also fuishes regulated 5 volt power
at the interce edge nnector. When n
structing customer interces, care should be
taken to avoid short-c rcuits or excessive loads
on this power supply. It is shared with the main
VLSI (Very Large Scale Integrat on) ntroller
which operates the printer, and any signals or
uctuat ons introduced on this l ne may aect
rrect printer operat on. Current nsumption
om the edge nnector should be limited to
200 milliamps to avo d overheating the printer
uni
PRINTING PAPER
Your SPRINTER is designed to use standard
themographic pr nting paper in roll or fan-ld
pack. A 2.5-inch diameter roll of paper, meeting
these specificat ons, has been ncluded with your
printer. Insure that the rrect paper is always
used, for the sensitivity and smoothness of
the paper s important r rrect operation of
the printer. Inrrect or low-quality paper may
result in po heat transfer, smearing and poor
pr nt ntras It is part cularly important to avoid
use of abrasive papers, which can cause severe
head damage in less than two hours of pr nt ng.
For qual ty pr nt ng and longer head life use
remmended grades of paper only. Refer
to the Appendix n the back of this manual
r a mplete summary of paper types.
Your SPRINT will accept fan-lded paper
in add tion to paper rolls. A n-ld stack should
be placed behind the printer and threaded under
the rear edge of the paper roll ver. Again, use
only remmended grades of paper.
3
4
LOADING ROLL PAPER
INTO THE PRINTER
Paper loading may be easily accomplished
by llowing th rrect steps. Refer to Figure 2.
SP 1
Lift the paper receptacle cover, and pull
the paper release lever rward.
STEP 2
For nvenience in paper insertion, it is
suggested that the paper roll is placed at first in
the fully opened paper receptae ver, with
the loose end ming om undeeath. Insert
the leading edge of the paper below the rubber
platen, and push geny with a de-to-side mo
tion until the edge of the paper appears on top
of the rubber platen.
STEP 3
Grasp the end of the threaded paper and
pull approximately 6 inches of paper thugh the
thermal head area. At this point, insure that the
paper is centered on the rubber platen, and is
aligned properly. When rrect alignment has
been confirmed, pull both ends of the paper to
insure that it is firmly wound around the rubber
platen and return the paper release lever to the
rear position.
STEP 4
Roll the paper supply roll rward into
the receptae. Grasp the leading dge of th
paper and hold it toward the ont of th print
ing unit, then ose the transparent ver.
STEP 5
Confirm that the paper is feeding cor
rectly by operating the manual paper advance
switch. Check that the paper remains pperly
center d within the thermal head area. When
you are satisfied that threading has been satis
ctorily acmplish d, excess paper may be re
moved, using the built-in paper tearing edge.
REMOVING A PARTIAL ROLL
OF PAPER
In the event that a partially-used paper roll
should be removed, l ow these simp e steps
STEP 1
Tear o any excess paper protruding
om the print head, using the built-in paper
tearing edge.
STEP 2
Pu l the paper re ease lever rward to
re ease pressure on the rubber p aten.
STEP 3
Open the paper receptacle ver, grasp
the partia ly-used l and ift it upward and to
the rear, moving it gently om side-to-side to
prevent binding in the print head area as the
paper is withdrawn.
Alteatively, the paper web may be cut
with scissors behind the ead-in slot to the
printer. The partia ly-used ro l may then be lifted
out, and the paper in the printer head ejected
by activating the manual paper advance switch
unti al of the paper has passed through the
print head.
LOADING FAN-FOLD PAPER
When using n- d paper, the stack
should be placed behind the printer. A slot is
provided at the rear of the transparent paper
ver through which the eading edge of the
paper should be inserted with the paper ver
closed. Push the paper rward unti the paper
receptac e is vered, then open the transparent
ver and use the same threading procedure de
sibed r l paper. Outgoing paper may be al
owed to stack in ont of the printer, or behind
the inming stack. Monitor the printer to insure
that the inming and outgoing stacks of paper
do not interfere with each other. Insure that the
sensitized (glossier) side of the paper has been
placed in ntact with the therma heads. If in
doubt, t o a sht length of paper and run it
through the print head using the manual paper
advance switch.
Checking the printer (test mode). A self test
mode has been built into the VLSI ntro ler,
to pvide a simple operationa check. When
p aced into this mode, the printer wi l repeatedly
print the character set across the paper in a con
tinuous patte. A test mode is entered by hold
ing the paper advance switch active and then
pressing the power switch ON. After approxi
mate y one send, the printer will begin to print
the character se It wil ntinue printing unti
the paper advance switch is released, where
upon it will enter the mode selected on the
mode se ector switch. The rrect operation of
the printer, the rrect loading of the paper, and
power avai ability can al be nfirmed in this
manner, without changing the nfiguration
of the printer or disnnecting it om its inter
ce. This test mode will a so demonstrate the
fast printout speed of which the SPRINT is
capable.
CUSTOM INTERFACING
Because there are so many alteative
methods of inteacing with various mputers,
this section wi l ful y exp ain how the SPRINT
interce operates, so that a custom inteace
can be nstructed, if desired. Interce sets r
specific mputers are avai ab e too. (Refer to
the owing section: Intercing to Specific
Computers with ctory Cab es.)
5
PARALLEL VERSUS SERIAL
INTERFACE
The SPRINTER is a very st synchronous
printing mech nism. While it is capable of
starting nd stopping r individual print lines,
it is most eicient when it is fuished data at
a rate which wi permit it to print ntinuously.
The VLSI ntroer includes a 40-character
buer which stores the character des to be
printed as they are tr nsmied om a host
mputer. This buer is fied until either the
40-character lit is reached, or until an open
"action de" initi tes the physical printing of
transmied char cters. The rmal n me of this
technique is "single line bufferin', ich indi
cates that the buer c nnot be refied until it
h s been "emptied" on to the paper by the
printer. The r te at which it c n then be refilled is
a function of the host mputer and the inter
ce mode selected.
The stest mode supported by the
SPRINT is e 7-bit parall interce. When
this mode is used, the SPRINT can be operated
at fu speed and wi appear to pnt continu
ously because it is not being slowed by the host
computer. The 7-bit parael interce is recom
mended bec use it is usually the least expensive
interce to build, and it will permit the unit to
be eectively used s a gr phic ploer. The
mode provides r 7 bits of d ta to be presented
to the SPRINT with a DATA STROBE signal in
dicating the validity of the d ta. The SPRINT
wi sign l that it c n accept the data with
"BUSY" signal which appears momentarily as in
ming char cters re being examined nd bu
ered, and during the physical printing action.
Data c nnot be regnized when the busy signal
is active.
6
A mplete set of lower serial interce
speeds are lso provided in the SPRINT VLSI
controller, using the d ta nventions of the
RS-232 data interchange proto The most
rapid of these proto
ls ta
k
es place at
00
bits per second and the least rapid at
11
0 bits
per second.
The serial transfer rate of
11
0
BAUD corre
sponds to print r te of ten char cters per sec
ond. Since the SPRINT can print
a
t up to
1
60
ch racters per
second (4 lines
x 40 characters
/
l ne), this
type of interce will seriously degrade
the per
rmance of the SPRINTER 40. If a serial
interce must be used
,
we enurage use of
the stest r te supported by the host mputer.
The serial interce software must also honor the
B
U
S
Y
signal. T
y
picay
,
it is routed to the host
through a
'
DATA SET READY
'
line on
the RS-232
nne
ct
or. With normal mputer wiring
,
this
wi m
k
e the sign l available to software on
a bit inside seria
l
interce ntroer I
C,
al
t
hough these devices are not used on all m
pu
ters
(
APPLE r example
)
. The polarity of the
sign l at the destinat
i
on mputer wi be deter
mined b
y
the intervening buers and inverters
and wi not necess rily be the s me in a m
pu
t
ers. Inter
ce c bles wi be available to in
v
ert
this sign l exte
l to the host mputer
;
other
c bles will be available which will require the in
version be cmplished in the host mputer
with software. In most cases
,
if two ST
O
P bits are
fu
ished
,
the B
U
S
Y
signal need only
be moni
tored
r
mpletion of the printing operation.
The buering step c n be accomplished during
the
S
T
O
P bits
r characters which do not
initi te printing.
OPERATION OF THE SPRINTER
40 PARALLEL INTERFACE
This section wi fu
ish explicit electric l
nd timing inrmation. Since a data in the
SPR
I
NT
4
0 are ended
into 7-t groups
(
whether ch racter or graphic in n ture
),
only
seven data lines are needed to transfer each byte
of inrmation. In the passive
p
arael cable
,
these d t li
n
es are interpreted as
L active
H
I
GH
dat levels. Thus a zero
(
0
)
bit would be
represented by a voltage level between
O
and
volts and a
one (1) bit
would be represented by
a volt ge level between
2
.4 and
5
volts. These
data bits are
uted directly to the ntroller de
vice and thus into the input gates of metal oxide
seminductor field eect transistors
(MO
S
F
ET
)
which require virtu y no curren
Thus while
they respond to
L volt ge levels
,
they re
q
uire
no power and can be driven by very low power
logic including
CM
OS logic operated at
5
volt
levels. This property ma
k
es them vulnerable
to damage
om high voltage static electricity
,
however
,
nd c re should be ta
k
en to avoid
touching the edge nnector
w
hile w
k
ing
on static-prone carpeting. In ddition
,
do not
permit si
g
nals higher than
5 v
olts to come into
ntact with these data lines.
In order to indicate the validity of the seven
data lines, another signal must be presented by
the host mputer to verify that it is placing valid
inrmation on them. This stbe signal is ac
cepted on the same trace on the edge nnector
as the serial input data stream. (NOTE: The
comete pinout of this edge connector may
be und in the Appendix.)
The DATA SOBE signal is represented by
a transition of this line om the L LOW level
to the L HIGH leve This transition may occur
at the same time that the seven data lines are
changed, thus permiing the entire output of
the host on a single eight bit por Upon receipt
of the DATA STROBE transition to the HIGH
state, the SPRINTER 40 will pause r approxi
mately 25 microseconds to allow the signals to
stabilize on the inteace cable, sample the state
of the seven data lines to determine the de
being sent by the host, and then assert the BUSY
signal as an active HIGH level to the hos The
host mputer must not alter the state of these
lines until the BUSY signal is removed (i.e. re
tued to the LOW level) by the SPRINT. As
long as this sequence is honored, any type of in
terce may be inserted between the host and
the SPRINTER 40. Just prior to the removal of the
BUSY signal, another signal known as acknowl
edge (ACK) is asserted by the SPRINT. This in
dicates that the fuished byte of data has been
processed. The ACK signal is removed simulta
neously with the removal of BUSY. ACK is fur
nished as an active LOW signal which retus to
a HIGH level upon the removal of BUSY. Thus
both a pulse type signal (ACK) and a level type
signal (BUSY) are available as a basis r n
structing other exteal parallel interces.
These signals were developed r a very fast
series of printers, to o
ccur very rapidly and to be
implemented in dis
ete hardware logi
In the
SPRINT
ntroller
,
these signals are im
p
le
mented in a mi
oprogrammed interce section
which
p
ermits the same hardware to be used in
several di
erent types of inteaces
.
As a result
the timing sequence is expanded althou
g
h the
same relative relations are presen Since most
host mputers implement their parallel inter
ces in software
they will be
q
uite m
p
at
-
ible with this technique. The basic software
se
q
uence llo
w
ed in the host should be
as llows
1. M
onitor the BUSY signal until it is inactive. I
f
it fails to be
me inactive
,
manual rrective
action must be taken.
2.
Remove the
D
AT A STROBE signa
3
.
A
ssert the
D
AT
A
STROBE si
g
nal and the
seven data signals.
4.
Pause approximately
3
0 microse nds.
5.
Confirm receipt of data by re gnition of the
BUSY signa
6
.
I
f BUSY not asserted
,
printer is inactive or in
-
terce has iled. Take apppriate manual
re very action.
7.
If BUSY is asserted
,
begin preparation of
next data byte
,
or next line of characters
,
as
appropriate.
8
. Retu to step
1
unless
a
ll
p
rintin
g
has been
ac mplished.
During
step 7, when
the data
om the ho
s
t i
s
either being bu
ered or prin
t
ed
, b
oth the host
and SPRINT
can be wor
k
ing in parallel. In
t
his
manner the host has the maximum time to pre
p
are
t
he next data byte while the SPRINT i
s
p
rocessing the previous da
t
a byte
,
or printin
g
t
he mpleted line of chara
c
ters.
T
his is an im
p
ortan
t
aspect
,
particularly when graphics inr
ma
t
ion is being transmitted to the
S
PRINT
.
The BUSY signal and
AC
K si
g
nals are pro
duced by an open llector circuit to prevent
p
roblems in the event that they are exteally
p
ulled low
.
This circuit is essentially a
47
0 ohm
resistor
t
ied to the SPRI
NT 5
volt supply and
pulled to ground by a transistor when these
signals are low. There is an additional invisible
clamping diode
b
uilt into the
t
ransistor which
nnects the lle
c
tor to
t
he main D
C s
upply
ca
p
acitor. In the event that an indu
c
tive load
should be
nnected
t
o either
o
f these lines
,
t
hese diodes would route any voltage excursions
over approximately
35
volts into the SPRI
NT
p
ower supply. While this is a highly unlikly pros
pect, the
interface designer should be aware of
its presence.
This inteace port can normally
b
e n
nected with proper cables to
a'Centronic type
inteace ca
b
le
,
although
j
umpers ma
y
have to
be modified in some of these units to produce or
honor the proper polarity of the BUSY or DAT
A
STROBE signals.
I
n most cases these inteaces
can be directly used without modification o
f
resi
dent BASIC software and system PRINT intrinsics.
The active Centronics ca
b
le contains slight hard
ware to standardize these signals to the highest
speed hard
w
are version of these signals.
7
SERIAL INTERFACING
When serial intercing is used, the
SPRINT ma onl be used as a character
printer. This is because it is logiscally impose
to furnish data rapidly enough to keep up
the rate at which dots must be fuished to the
printer at the serial transmission rates. For more
information refer to the GRAPHICS section of
this manua With higher Baud rates, such as
00 Baud, ver high character printing rates
may still be achieved. When using serial interfac
ing, only three data lines are required, SIAL
DATA, GROUND, and BUSY. The data rmat
used is the RS-232 format r serial data with the
s
ame AS
CI
I chara
c
ter en
ding u
s
ed
r all print
ing. The
s
erial inter
ce
l
oo
ks
r a START bit
,
eight data bits, and ne or more STOP bits.
The inrmation
in RS-232 is
theoreticall
y
en
d
e
d a
s
a po
s
itive and negative volta
g
e
s
wing centered at
z
ero volt
s
. Signal
s
mu
s
t
theoreti
c
ally
s
wing more po
s
itive than
3 v
olt
s
to represent a logic zero (0) and more negave
than
3
volt
s
to repre
s
ent a logic one
( 1 )
. The
SPRINT
E
R i
s
more tolerant than thi
s
in it
s
inter
pretati
o
n
;
an
s
ignal more po
s
itive than 2.
4
volts will be recognized as (0) and any sign less
than .
4
v
o
l
ts w
ill be re
gni
z
ed a
s
logic one
(1 )
.
Thi
s
i
s
ac
mpli
s
hed by a
s
imple circuit on the
SPRINT
ntroller board which permit
s
either
normal
L level
s or RS-232 levels
to be
n
nected
to
the SI
AL D
ATA
A
T
A STR
OBE
line.
It will a
lso
w
o
rk with C
M
OS logi
c
, operated at
5
volt level
s
or higher, providing the lo
g
ic low le
v
el
i
s
le
ss
than .
4
volt
s
.
8
START BIT
DATA0
DATA 1
DATA2
DATA3
DATA4
DATA 5
DATA6
DATA 7
STOP BIT
STOP BIT
(HIGH)
(HIGH)
(LOW)
(LOW)
INTERFACING TO SPECIFIC
COMPUTERS WITH
GENERAL PU POSE CENTRONICS CABLE
Thi
s
ca
b
le i
s
a
v
ailable with the male
36
pin
"
tongue and groove
"
nnector
.
A printed cir
cuit in the cable contains logic t
o standardize
s
ignal
s
om the
s
our
c
e and to pe
orm cro
ss
connections t the SPRINTER cable. This is an ac
tive de
v
i
c
e an
d
i
s p
o
w
ered
om the
5
volt
s
upply
in the S
P
R
I
NT
w
hile it i
s p
owered up.
GENERAL PURPOSE RS-232 CABLE
Thi
s
cable i
s
wired to mate with normal RS
-
232 cables and acts as a 'data se. It fures
a
"
d
a
t
a s
et rea
d
" s
i
g
nal
g
enerated
om the
SPR
I
NT
BUSY
s
ignal and terminate
s
in
a 25-n
male 'D' type connector. The board includes
several jumpers for optional generation of the
s
peci
a
l
s
ignal
s
re
q
uired b
y s
ome
mputer
s
. It
terminates in an edge connector for direct con
nection to the SPR
I
NT
E
R. It i
s
al
s
o
p
owered b
y
the SPRINT
.
GENERAL PURPOSE PASSIVE CABLE
Thi
s
c
ab
le fu
i
s
he
s
the SPRINT
ed
g
e
n
ne
c
tor on one end of a ribbon
c
a
b
le,
g
ivin
g
the
u
s
er
a
cce
ss
to every
s
ignal in the SPRINT inter
c
e
,
in
u
ding the SPRINT
5
volt power
s
up
pl
y
.
E
ither
s
pe
c
ial
s
erial or parallel connector
s
ma be
nnected to thi
s
cable to ma
k
e a cu
s
tom
s
erial
o
r parallel i
n
ter
ce r the
mputer.
The
p
in
o
ut of thi
s
c
able i
s
included in the cable
pac
k
age.
After the tran
s
mi
ss
ion of the
mplete
b
y
te, tran
s
mi
ss
ion of the ne
x
t b
y
te may begin
if it i
s
ready. If not, the data line
hould a
ss
ume
the inactive level which i
s
repre
s
ented
b
y a
L
O
W
leve The BUSY line will
b
e a
ss
erted durin
g
th
e
START bit and
w
i
l
l be removed durin
g
either the
fir
s
t or
s
e
nd STOP bit, dependin
g
upon the
data tran
s
mi
ss
ion rate
s
elected. The
B
USY
s
ignal
will thu
s
ha
v
e been removed bere the ne
x
t
ST
A
RT bit time interval
b
egin
s
, unle
ss
the printer
ha
s
i
n
itiated a
p
h
ys
i
c
al printing operation.
When the definition
of RS-232 is
e
x
amined,
the
S
T
A
RT
b
it emer
g
e
s
a
s
a
HIGH (>2.4 VOLT)
s
ign
a
l an
d
the
S
T
O
P bit emerge
s
a
s
a LO
W
(
<
0
VOLT) signal. Data ts appear as apparently in
verted, in that zeros are represented as HIGH sig
nals and
o
n
e
s
are repre
s
ented a
s
L
O
W s
ignal
s
.
Although eight data bit
s
mu
s
t be tran
s
mi
ed
and received
,
the
s
even bit ASCII
din
g
u
s
ed
implie
s
that the eighth bit mu
s
t
b
e a logic
z
ero,
i.e.
a
H
I
G
H data bi
(
The
v
alue i
s actually ig
nore
d
.
) D
at
a b
it
s
are tran
s
mi
ed lea
s
t
s
ignificant
b
it fir
s
t t
h
ug
h m
o
s
t
s
ignifi
c
ant bit la
s
The
s
e
quence i
s
thu
s:
TRS-80
The SPRINTER 40R-80 interface cabl is
a parallel interce cable which responds to bus
addressing, latches data r the SPRINT, and
fuishes a readable response to interrogation
of the BUSY signal recognizable by the standard
TRS-80 software. This interce ntains several
active devices and is automatically powered by
the SPRINT inteal power supply. A sche
matic of the unit is inuded in its package. With
this unit installed, it will be necessary to power
up the SPRINT whenever the TRS-80 is operat
ing, to avoid interference with the inteal bus
of the TRS-80. No modification of the TRS-80 is
required. This unit connects directly to th
TRS-80 keyboard edge nnector.
Interce can also be acmplished with our
general Centnics standard cable using one of
the Radio Shack Centronics interce devices.
This alteative may be useful if one of the Radio
Shack interces is already available.
APPLE CARD
The SPRINT 40/APPLE interc cable is a
circuit board, to be inserted in th APPLE m
puter in one of the device slots. The card draws
power om the APPLE power supply and pro
grams the APPLE 6502 processor to ex cut
required protol to mmunicate with the
SPRINT, using the parallel inteac . The inter
ce card ntains software to dump all Apple
displays on the SPRINT by pressing keys on the
keyboard. It also nnects th SPRINT to re
spond to APPLE SOFT print mmands to permit
nmal printing. The SPRINTER does not have to
be powered up when using the APPLE int rface
card unless printing is actually und r way. The
APPLE card requires no modification to the
APPLE computer, and obeys the protol of the
APPLE r transferring data to a d vice ntrol
le It may thus be used with APPLE SOFT BASIC
or other standard Apple-fuished software
packages r character printing. The inteace
card includes a cable which nnects directly to
the edge nnector on the rear of the SPRINT.
The Apple can also be used with our active
Centronics cable driven by the Apple Centronics
printer card, but this is an xpensi
v
e m
b
ina
tion and is not remmended unless the
A
pp
l
e
card is alread
y
available, since it does not in
ude
s
oftware r printing Apple displa
y
s
.
P INRFACE
The PET interce re
q
uires a modified
SPRINT to support the PET character se
t
This
modification perrms the necessary
pt
o
l
o
f
the IEEE-488 inter ace
an
d
allows the PE
T
IEEE
bus nnector to be daisy-chained to the
SPRINTER in acrdance with the bus philoso
phy. e
special SPRINT unit sold
r this
p
ur
pose will inude the specia
l
interconnect cabl
e
re
q
uired to nnect to the PET computer
.
Th
e
PET modification deletes some standard featur
es
of the SPRINTER to make it more uniquy suited
to the needs of the PET
.
Check with your
SPRINTER supier for avlality
ATARI 400 AND 800
The ATAR
I
mputers can be inter
ced in
several wa
y
s
.
The ATARI mil
y
of mpon nets
includes printers which intea
c
e directly to the
main unit, thus nsuming som
e
of the inter
ce
ports, and printers which interc to the AT
AR
I
8
5
0
C
entronics port, which th n retains the a
b
i
l
it
y
to perrm additional inteacing
.
Our ca
b
lin
g
interces to the 850
C
entronics port through
use of a simple interconnect cable
.
In this man
ner, e
SPRINT is directly accessibl throu
g
h
nmal print logic in both the 400 and 800 m
puters. Use
of the serial ports on the 850 is not
remmended, because the ster parallel port is
available
.
MATT INT ISION
An inteace to the
M
a
el
k
eyboard unit
will be made available r direct inter
ce in the
near future
.
Check your suppli r
r availabil
i
ty
.
CHARACTER PRINTING
Character
p
rinting ma
y
be simply acm
plished om all interfaces
. T
he SPR
I
NT re
g
ni
z
es
9
6 AS
C
II character des as printable
characters and prints them
.
In addition
,
it re
g
nizes certain other des with numerical values
between
O
and
31
decimal as action d s
,
which can trigger changes of printing mode
.
Each of these action des is e
x
plained below
.
The chara
c
ter nt and association
w
ith ASC
I
I
representation are presented in the Append
ix.
Character mode of o
p
eration is
a
ssumed
when the printer is powered up
.
At this time the
print bu
er is eared
,
the printing speed is set to
ur lines per second, and the mode s
w
itch is
tested to determine the inter
ce mode and type
of paper being used
.
Characters wil
l
be accepte
d
into the inteal print bu
er until either the ac
tion code 'CR' or 'LF' or CNTRL-R are received,
any of which will initiate physical printin
g. A
ny
characters in excess of the first 40 printable char
acters sent prior to one of these
a
ction des wil
l
be i
g
nored by the SPRINT
;
the receipt of these
characters will a
ect nothing
b
ut
r the ti
me
nsumed in their transmission
.
Follo
w
ing the
ph
y
sical printing of any line
,
the print bu
er is
immediately eared bere a
c
cepting additional
characters
.
9
Carriage Retu Decimal (13)
Octal(15 Hex (D)
The 'CR' character is used to cause no mal
p inting of a cha acte line. If fewe p intable
cha acte s than 40 have been buered p io to
the receipt of this code, the buffered characters
will be printed starting at the leftmost column on
the page. Blank characters will be p inted in the
emaining ight lumns esponding to the
empty positions in the bue . Since many m
pute s ntain softwa e which gene ate
the 'CR' and 'LF' in paired combinaons, the
SPRINTER will ignore the send of these if they
are sent in pairs. The physical p inting operation
will begin when any of the three des a e
eceived. If this operation is llowed by the e
ceipt of one of the other des, this send de
will be abso bed by the ntrolle without ac
tion. Subsequent eceipt of every epeat immedi
aty follong one of these des will result in
the printing of a single blank character line. This
patte is b oken by the receipt of any other
de by the nt olle .
Line Feed Decimal (10) Octal (12)
Hex (A
The LF code functions identically to the Ca
iage Retu
. A
carriage retu llowing it will
be a
b
so bed
(
in a simila manne to the situation
d
es
i
b
ed
r
Carage Return.)
10
CNL-R Decimal (18) Octal (22)
Hex (12)
This a
ct
ion
de is treated identically to the
ca iage etu and has the same elationship to
the line feed de
.
The only manne in which it
diers i
s
that when it initiates physical printing
,
an
d
the printed bu
e ntains fewer than 4
0
ha acters
,
the bu
e ed cha acte s will be ight
j
ustified in the p int buffe
,
and the
vacated posi
tions will be filled with blanks prior to printing
.
Thus in
rmati
o
n will appea to have been
s
h
ifte
d
to the ightmost lumn prio to bein
g
p inted
.
The use of
the CNTRLR is
to sug
g
est
Right justif
VERTICAL-TAB Decimal (11) Octal (13)
Hex (OB
This acti
o
n
ode llowed by anothe
de c
a
uses the S
P
RINT
to e
x
ecu
t
e a multiple
line feed
.
The ne
x
t de transmitted after the
CNTR
L-M
is inte preted by the SPR
I
NT
as a bi
na y number, indi
ating how many lines should
be skipped in the multiple line feed
.
The mean
ingful range of values are
1
th
ugh
127, repre
sented as
some
7-
bit
A
SC
I
I de
.
Pre
isely this
man
y
lines will be printe
d
as blank cha acte
lines
llo
w
ing receip
t
of the second de
.
FORM FEED Decimal (12) Octal (14)
Hex (0C
R
eceipt of this de causes the SP
R
INT
to skip eight lines if the
n
-
ld switch is set to
roll paper," or
in all early units
. I
n late units
,
if
the swit
h
i
s set to
n ld pape mode
,
receipt
of this de
w
ill cause the SPRINT
to skip to
the head of the ne
x
t logical page, based on the
si
z
e and its position on the
urrent page
.
CNTRL-G Demal (7) Octal (7) Hex (7
This de can be thought of as an escape to
G
R
A
P
H
ICS de
.
It can be received when using a
parallel inter
e capable of supplying data rap
idly to the printer
. F
ollowing eceipt of this de
the SP
R
INT
w
ill immediatel
y
actuate the p int
mechanism and en
t
er g aphics mode of ope a
tion. It w
ill emain in this mode as long as data is
re
ei
v
ed rapidl
y
enough to satisfy the data rate
required by the mong printe If at any time
data is not re
eived r prin
t
ing,
t
he printe will
be stopped an
d
the ntrolle will clear the print
bu
er an
d
etu to no mal cha acter mode
.
T
his de ma
y
be meaningfully eceived llow
ing powe up, or a
t
any time when the p int
bu
er has bee
n
cleared
.
If it is eceive
d
when the
print bu
er n
t
ains inrmation, the n
t
ents
of
t
he
b
u
e will be clea ed pri
to sta ting the
printer
. F
o mo e in ma
t
ion efe to the section
on GRAPHIC
CNTRL-S Decimal (19) Octal (23)
Hex (13)
Lat
er m
o
dels of the SPR
I
NT
in
ude the
a
b
ilit
y
to
co
n
t
rol the speed of the
print mecha
ni
s
m a
t
three di
erent speeds
. W
hile
t
he normal
spee
d
of
th
e unit at power up is ap
px
ima
t
ely
ur lines pe send
,
the p in
t
mechanism can
als
o
be
o
pe ated at
t
hree and two lines per sec
ond. Ts
a
t
i
o
n is initiated by
t
he
t
ransmission
of
the CNTRL-S code
llowed by an
ASCII de
ma
l v
alued de of either
2
,
3
, o 4
(
see table in
the
A
p
pendi
x
r the
A
SCII name of
ese codes).
The abili
ty
to respond
t
o speed n
t
rol is
a func
tion of
t
he
V
LSI n
t
roller and early uni
t
s can
b
e
u
p
dated t
o
o
bt
ain this ability by replacemen
t
of
the n
t
r
o
ller
.
T
he p imary purpose of
t
his ability
is
t
o
ed
uc
e the da
t
a a
t
e require
d
om the hos
t
mputer durin
g
graphics mode
.
CNTRL-Q Demal(17) Octal (21)
Hex(11)
This de is used in later units to set the
logical page size of n ld pa er. (See auto-n
ld mode.) This de must be llowed by a
subsequent de which is interpreted as the bi
nary value (1-1) of the logical age. A size of
ze will be ignored. When this de is received
the printer is assumed to be set to appro
mately three lines om the to of a age.
AUTO-WRAPAROUND
Later models of the SPRINT also inude
the ability to 'wrapaund' any characters in ex
cess of the 40 characters which will fit onto the
normal print line. In this mode, the printer inter
ce will go 'BUSY' llowing the receipt of the
fortieth aracter and will physicay pnt the
characters in the buer, ear the buer, and re
tu to accept more characters. In this manner
if e host contains unmodiable software (su
as in a ROM BASIC system) which will try to print
character lines wider than rty characters, the
SPRINTER will automatically print these extra
characters on the llowing line rather than trun
cating them. This permits the SPRINT to be
used in applications rmerly requiring an 80 l
umn printer. Auto-wraparound i
s selected by
one of the mode switches located in the paper
feed chute.
W
hen operating in auto-wra around
mode
,
it is
p
ossible to have the SPR
I
NTER lef
t
or righ
t j
ustify any par
t
ial line
w
hich is wr
a
pped
around. In this manner
, t
he
t
ail end of lines may
be displayed n the ght de of the page which
is more aesthetically pleang to some observers,
particulay when tabular oented information
is
b
eing printed such as assembly languages
or
P
ASCA
L
. The right
j
ustified
w
raparound
matches the style used
b
y many p
g
rammers
of right
j
ustifying short continuations of lines of
pgram code rather than ntinuing
t
hem to
the beginning of the llowing line
.
The ri
g
ht or
left justify mode is only funconal when auto
wraparound has been selec
t
ed.
T
he lo
g
ic
r
both auto-wraparound and au
t
o-
j
us
t
ify are n
tamed in the VLSI controller and are available on
any S
P
RINTER using
t
he later model ntroller
chip.
AUTO-FAN FOLD PAPER
MODE
F
an-lded paper may be used
w
ith an
y
SPRINT. A slot at the rear of the paper ver
permits external paper inser
tion. Later mods
also inude additional
l
ogic in the ntroller to
trac
k
the volume of material
b
eing printed on a
nceptual page of paper, and to s
k
ip a
oss
t
he
fd line betwee pages automaticay. ere is
n
o hardware outside the controller to physically
identify
t
he page boundary. The page boundary
is determined by instructing the controller
t
hrou
g
h the transmission of CN
L
llowed by
another code indicating the number of lines
which should be on the page. This number is en
ded as the number o
O
TA
L
lines on the
page
,
inuding si
x
blan
k
l
ines printed by the
con
t
roller when
t
he end of the
l
ogical page is
reached. when
t
he SPR
I
N
T
reaches
t
his T
O
TA
L
-
6
lines
,
i
t
will au
t
oma
t
ica
l
ly print si
x
blan
k
lines,
p
lacing three of
t
hese at the end o
f
the
current page
,
and
t
hree o
f
t
hem a
t
t
he
t
op o
f
t
he
f
ollo
w
ing page.
When paper is
l
oaded in
t
o
t
he SPR
I
NT
and the fan-fold mode is active, the SPRINTER
will assume
(
at power up
,
or
l
l
o
w
ing any use o
f
the PAP
E
R A
DV
ANC
E
swi
t
ch
)
,
that the opera
t
or
has positioned the paper appromately three
l
ines
om the
t
op of a new shee
The SPRIN
T
will subse
q
uent
l
y hold
t
his appro
x
imate posi
t
ion
a
t
the
t
op of llowing pages, assuming tha
t
i
t
has
b
een programmed with
t
he per line
length. The deu
l
t page si
z
e has been se
t
r
t
he 11-i
n
ch-h
i
gh paper remmended r use
with
t
he SPRIN
T
. Since
t
he SPRINT canno
t
dis
t
inguish whe
t
her n-ld paper is being
used, this mode may also be
used with roll pa
per.
In
t
his manner
,
pseudo p
a
ges of u
t
o 1
2
0
physical lines may be printed on roll a er, wi
t
h
si
x
-line
g
aps automatica
l
ly being inserted by
t
he
SPRI
N
T
as te
x
t is prin
t
ed. This p
e
rmi
t
s
t
he o
era
t
or to cut
t
he prin
t
ed areas apart, or ld the
ou
t
put to achieve a n-ld lis
t
ing. The ntrol
ler also acunts
r pa
g
e len
g
th durin
g
t
he
printing of raphics mateal, so at pictures
ma
y
be me
rg
ed wi
t
h norm
a
l
t
e
x
t withou
t
inter
f
erence wi
t
h page boundaries.
H
owever
,
if
graphics mode is entered and n
t
inued across a
pa
g
e end, the SPRINT wil
l
prin
t
a ntinuous
bloc
k
of graphic materia
F
an-ld paper can be used on
a
ny model
SPR
I
N
T
without the use of
t
he
a
uto-
f
an
f
old
feature. In this case
,
prin
t
ing
w
ill occur a
oss
t
he ld seams of the aper, producing
a
ntin
uous outpu
11
PRINTING GRAPHICS
INFORMATION
The graphic ploer mode is provided in ad
dition to the normal mode in which in rmation
is sent to the SPRINT as ASCII des causing it
to draw the nts of characters om its inteal
character pae memory. In plot mode, the
host mputer sends the same 7-bit bytes of in
rmation, but the actual bits sent are plotted as
dots aoss the 280-dot line of the printer. Each
of the 40 thermal dot sites prints seven dots,
producing the total dot line. The prinng mecha
nism must run ntinuously because there are
no interline blanks. All data transfer to the
SPRINTER takes place while the print heads are
reversing direction. The high speed of the paral
l interface is required, since forty bytes must be
transferred during each reversa
In a normal application, the host mputer
will develop a graphic bitmap or plotting array of
dots. This will represent the dot data transferred
to the SPRINT when ploing. The role of the
host mputer is to prepare, as necessary, the
next dot line while the previously transmied
line is being printed. When operating the
SPRINT at ur lines per send, this implies
that rty dot lines will be printed each send,
or that a complete dot line will be printed each
twenty five millisends. The host mputer
must be able to prepare rty bytes of data dur
ing approximately twenty millisends, and
transfer it during the remaining approximately
five millisends. Short, simple assembly lan
guage routines running in any of the mmon
host mioprocessors will normally meet this
requirement.
12
GRAPHICS DATA TRANSFER
Upon receipt of the CNTRLG code, causing
entry to graphics mode, the ntroller will start
the print mechanism and allow it to accelerate to
speed. When a mplete pair of blank dot lines
has been printed and the print mechanism re
verses its direction of travel, the BUSY ndition
will be removed om the interce and the
SPRINT will
a
empt to ac
c
ept data om the
host mputer
.
It can accept rty bytes, of
seven dots each
,
within a spe
c
ified period of
time determined by the rate of speed at which
the mechanism is operating
. L
ater units allow
the speed to be varied
between 4, 3,
and 2 line
s
p
er send
.
As the SPRINT
E
R is waiting r data
to be re
c
eived
,
a timing unter is activated r
each byte
.
If the data byte has not been received
be re this unter
ears
,
the interce signal
s
the ntroller that a
'
graphic timeou
has oc
curred
.
This will result in an exit
om graphics
mode and a retu to the mode established be
re
g
raphics mode was entered
.
This timeout
insures that all data can be received prior to th
e
thermal heads passing the
p
oints at which the
y
must
p
rint the bu
ered dots
.
The tran
s
mi
e
d
dots are stored in the inteal bu
er and print
ing oc
rs as the mechanism passes over the
proper position on the paper
.
Upon recei
p
t of
the rtieth byte of inrmation r each dot line
,
the SPRINT inter
ce will remain
BUSY u
n
ti
l
mpletion of the physical printing operation
.
No expli
c
it action de is required or allowed r
initiation of the physical printing
.
The timeout
period r each byte transfer to the SPR
I
NT
i
s
given in the llowing table r ea
c
h
p
rinti
ng
speed
:
41ps
31ps
21ps
40
s
70s
100
s
40
s
130 5
220
s
Printing Rate Max time between (later units)
OT BUSY and next DATA STROBE
ORIENTATION OF THE
GRAPHIC MATRIX
W
ithin ea
c
h line of dots
,
the first
b
yte of
data plotted will be placed in the leftmo
s
t
p
r
int
lumn and the rtieth byte will be
p
laced i
n
the rightmo
s
t lumn
. T
he most signifi
c
a
nt bit
within each b
y
te
(D
ATA
6)
will be
p
rin
t
ed i
n th
e
leftmost side of each byte and the
least signi
cant bit
(D
AT
A
0
)
will be printed in the rightmost
side of each byte of dots
.
The printed image will
be, at
most, 280 dots
in width, but there is no
particular limit on its length
,
as long a
s
da
t
a
c
a
n
be fuished rapidly enough
.
In most mputers,
the realistic limit will rrespond t
o
the
s
i
z
e o
f
the
b
itmap which can be stored in the host
m
putes memory.
In some applications it may
help to think of the image rotated
90
degr
e
es
.
F
or example
,
it would be impossible to
p
ri
nt th
e
ntents of an eighty lumn display across the
width of the printer
,
but quite possible to d
u
m
p
this same inrmation rotated
9
0 degrees
s
in
c
e
such an image would require
typically 240 dot
lines in height by
56
0 dot lumns in wid
th.
Whenever the printing mechanism is
s opped at the completion of a blo of grapc
printing, there wl always be a group of several
blank dot lines, rresponding to the accel
era ion and decelera ion time of the print
mechanism. It is impossible to eliminate his
phenomena, but his will normally cause no
problem because some interblock spacing is usu
ally desirable between graphics and surrounding
tex
GRAPHICS BROWNOUT
More power is used in the nversion of he
hermal paper than is needed to operate the
printer motor or he ntroller board. Normal
character printing nsumes a rela ively small
amount of power since character paes are
relatively sparse, and charac ers are separated by
blank lumns and rows. When printing graph
ics, potentially many more dots must be pro
duced rresponding to 'black' areas in the do
raster. While all-black ras ers are not particularly
interes ing or useful, they can conceivably occur.
To avoid his the SPRINT has been designed to
print at full speed a 50% du y cycle. It will prin
half fewer of the dots a full speed, or, in la er
models, all of the dots at half speed (2 lines/sec
ond) Some additional reserve capacity insures
that short burs s of dark prin ing (several dot
lines) can be prin ed normally if his ndition is
not sustained.
In the even tha sustained dark printing is
aempted, protective circuitry in he SPRINT
power supply will activate thin approximaty
eigh dot lines and reduce the power to the print
mechanism. This will appear as a slowing of the
printer and a ligh ening of the prin image. This
ndition can be thought of as a power brown
out. It means "SLOWDOWN!" en the unit is
opera ed at one of the lower speeds such as 3 or
2 lines per send, the rate of power usage is in
here
ntly reduced.
It is recommended that 2 lines
per send be used
r printing of very
da im
ages.
I
f sustained black printing is a tempt
e
d
,
a
protective hermal fuse in the power supply may
also be activated. This will necessitate opening
the printer case and replacing he fuse be
re
he printer can be used f
u
rther.
CUSTOMER SERVICING
OPERATIONS
In normal operation your SP
RI
NT
should
print many hundreds of thousands of lines wi
t
h
out re
q
uiring service. The
llowing
ser ice oper
a ions are described because they might be
re
q
uired eventually. We want you to know how
to per
rm hem rrectly if they should become
necessary.
OPENING THE
SPRINTER CASE
STEP 1
UN
PL
UG
T
HE
SP
R
INT
FR
O
M
ITS
WALL
OU
T
LE
T
A
ND T
HE H
OST
CO
MP
U
T
. Never
a
t
tempt to per
rm any service step with the
u
nit
nnected to any other device.
R
emove any roll
paper ntained in the paper mpartmen
STEP 2
Remove
the plastic handle
om the pa
per release lever by pulling up on the handle
,
without bending i The handle is held by
iction
on the le
v
er it vers.
STEP 3
Pull ou the
ur small rubber feet under
the case. The feet are held in place by
iction.
This will provide access to
ur recessed s
ews.
Remove the s
ews with a small strai
g
ht blade
s
ewdriver by rotating them unterclo
c
kwise.
STEP 4
H
old the case together while it is t
u
ed
upri
g
ht
,
then lift the upper case
om the lo
w
er
case.
CLOSING THE SPRINTER CA E
STEP 1
I
nsure that the paper release lever is
placed in the
rward position. Insure that the
power cord strain relief is inserted into the open
ing
i
n the rear of the case. Insure that the
p
rin
t
er
is firml
y
a
ached to the nt
ller board
,
and
that all circuit boards and he power trans
rmer
are firml
y
aached to the lower case. Insure that
no
rei
g
n ob
j
ects
(
tools, screws,
paper, etc.) re
main inside the case and that the ventilation slots
are unobstructed.
STEP 2
ace
the upper case on top of the
lower case
,
and align rrectly.
H
olding the two
case halves together, invert the unit and reinstall
the
ur s
ews. Reinsert the
ur rubber feet
into the s
ew holes on the lower case. Note that
these feet are necessary to insure that the
SPR
I
NT sits high enough to allow ventilation
of the case.
STEP 3
R
einstall the paper release lever on its
shaft and load the printer with paper.
STEP 4
Place the printer into self test mode to
nfirm rrect reassembly.
13
REMOVAL OF THE
PRINTER MECHANISM
STEP
1
Release the ribbon cables by lifting alter
nately on each end o each nnector and re
moving the ribbon cable at an angle. If the
nnector appears to bind, do not rce it, but
work alteately at each end o the nnector
until it loosens. There are two 21 potion n
nectors, and a small 6 position nnector.
NEV SHARPLY FOLD E RIBBON CABLES AS
IS MAY CAUSE INTNAL FAILURE OF E
PRINT CONDUCTORS AND MAY REQUIRE RE
PLACEMENT OF E PRINT MECHANISM.
STEP 2
Remove the four 8-32 screws holding
the printer to the posts on the printed circuit
board. Lift the printing mechanism vercally un
til it is clear of the mounting posts.
REPLACEMENT OF THE
PRINTER MECHANISM
STEP
1
Replace the print mechanism on the ur
mounting posts. Reinsert the ur screws hold
ing the printer to the posts.
STEP
2
Replace the two 21-posion bbon n
nectors into their respective sockets by holding
irmly onto the reinrced area just above the
edge o the nnector, and pressing them verti
cally into the nnectors.
STEP
3
Replace the smaller nnector, insuring
that the wires pass under the edge of the sheet
metal just behind the socket and emerge to the
right side o the connector. The ribbon should
not be rced rward. Insure that the ribbon
portion of the cable rises up and over the er
of the printing unit and that it does not inter ere
with either the nnections to the printer motor
or the nearby other ribbon nnector. BE PAR
TICULARLY CAREFUL AT YOU DO NOT
SHARPLY FOLD IS SMALL RIBBON CABLE AS
YOU INST E CONNEOR.
14
REPLACEMENT OF
THERMAL HEA S
STEP
1
Remove the printer mechanism as de
scribed abov
STEP 2
Locate the wire spring which extends
om the top su
ace of the thermal head pres
sure plate around under the printer to a metal
oss bar on the underside o the printer
.
Place
a thin bladed s
ewdriver between the spring
and the metal
oss bar, and li t the spring
ee o
the small hole in which it resides
. P
errm the
same operation on the end o the spring inserted
into the pressure plate, on the top side
.
The
s
p
rin
g
may now be slid out of the
print mecha
nism, leaving the pressure plate pressed lo
o
sely
a
g
ainst the platen
SP
3
G
ently work the pressure plate out
o
the
positioning notches
.
The pressure plate will not
release entirely om the printer
;
the goal is to
release it enough to obtain access
t
o the under
side of the pressure plate by li ting and lding it
back ards, away from the platen.
STEP
4
Loosen
the small s
ews holding the
sprin
g
ingers agains
t
the thermal head
,
until the
thermal head can be slid om under the fingers
.
STEP
5
Install the new thermal head
,
being c
a
re
ful to ali
g
n the nductive pads in
t
he head with
the ndu
ct
ive
p
s on the end o the ribb
o
n ca
ble. Tighten
the small s
ews alon
g
the pressure
ate.
STEP 6
W
ork the pressure head back into the
p
ositioning slo
t
s and reinstall the pressure
s
p
ring
.
Note that the sprin
g
is not s
y
mmetric
a
l
,
but has a to
p
and bo
om side to help clear the
ribbon nnector
.
Ins
t
all the spring to m
a
t
c
h
th
e
orientation o the undisturbed si
d
e
.
STEP
7
If necessary
,
replace the other therm
a
l
head using the same procedure
.
SP
8
Repla
c
e the printer mechanism
,
llowing
the above instruction
,
and close the SPRINT
case
.
The printer may then be tested using test
mode.
STEP
9
The printer should now be fully opera
tional i the work has been success ully m
eted. It
may be necessary to prin
t
r a while
a ter ser
v
ice work,
t
o allow the pressure heads to
seat and
t
he heads to wear in
.
Noticeable print
li
g
htness o either head
,
or print lightness
a
t one
side of either head indicates inrrect se
a
ting
o
the pressure plate
.
Correct and adjust bere
printing
.
Contact with paper is impor
t
ant
;
it
must be unirm to avoid damage to
t
he new
heads.
STEP
10
If there is sligh
t
relative misalignment
between the two thermal heads
,
either of the
heads ma
y
be moved sli
g
htly with a small s
ew
driver after installation until satis
c
t
ory align
men
t
is achie
v
ed
.
This must be a small move
ment, to avoid breakin
g
ntact between the
nduction si
t
es on
t
he head and the ribbon
cable under the pressure pla
t
e
.
PAPER JAMS
Under normal operation, there should be
no problem with paper jamming in t e mecha
nism. In the event that small roll-ends of paper
are removed or reinstalled into the printer, care
should be taken that the tightly rled paper
does not wrap under the paper stripper bar dur
ing the loading operation. If this does occur, the
paper may begin to wrap around the platen until
a thick roll of paper builds between the pressure
plate and platen and stalls the printer. This is a
diicult situation to remedy since the platen will
not readily rotate backwards. It is best avoided
by careful loading practices.
If such a jam does occur, unplug the
SPRINT to remove power and try the llowing
techniques to remove the jam.
1.
Release the pressure lever, tear o the supply
of the paper, and aempt to push the inming
paper into the mechanism, thus unwinding it
om the outside of the spira This will have to
be repeated r as many times as the paper is
wrapped aund the platen.
2.
If this method ils, slicing the paper aoss
the roller may have to be aempted. An alterna
tive is to remove the print mechanism om the
case and massage the paper om around the
roller.
3. NEV under any circumstances place tools
between the thermal heads and the platen. The
probability of damage to the thermal heads is
very high under these circumstances.
The best solution to this problem is PREVEN
TION, by careful loading of the printer in the first
place and monitoring the correct feeding at the
initiation of printing.
LUBRICATION
The printer mechanism does not normally
require lubrication. Small amounts of grease are
located on the oscillating bar where it enters
the metal side plates of the printer. Unless this
grease bemes ntaminated with dirt or other
reign material, it need not be replaced. Pro
longed operation of the unit at high tempera
tures may cause the lubricant to thin excessively.
In the unlikely event that this ocrs, a slightly
heavier lubricant may be applied to the sliding
ntact surfaces. The motor is permanently lu
bricated and should not require additional lub
cation during its service life.
DOT TIMING ADJUSTMENT
The ntroller board ntains a potenom
eter which is factory adjusted during assembly to
set the thermal dot heating time correctly. This
potentiometer should not be used as a 'volume
ntrol' to set user-preferred dot intensity levels.
Operation at the extreme dark setting with nor
mal tolerances on mponents may result in ex
cessive heating times r the thermal heads. The
ctory setting is diicult to restore without a
logic analyzer or storage oscillospe, so tam
pering is unwise.
DOT AGNMENT
In the event that a replacement print me
anism is installed, it may be necessary to adjust
the dot alignment drum on the printer. This is a
serrated white plastic tab extending slightly om
the rear of the printer behind the motor m
partmen On new printers, this drum is secured
with adhesive on the tab and/or on another
smooth tab extending slightly om under the
right side of the printer. The adhesive may be
acked by slightly moving the tab left or righ
M
oving this tab will cause alte
ate rows of dot
s
to move left or right with respect to each other
,
thus achieving vertical alignment between row
s
.
The easiest method r achieving alignment
is to place the SPRINT
into self test mode and
then adjust the tab while it is printing. Sin
c
e this
must be acmplished with the protective case
open
, W
E
D
O NOT
R
E
C
O
MM
EN
D
AT
I
S
STEP
B
E UN
D
TA
K
EN
BY
E O
W
N
D
UE
TO
E
P
OSSI
BL
E E
XP
OSU
R
E TO
NE VO
L
T
AG
ES IN
SI
D
E
E P
L
ASTI
C C
ASE.
FUS SERVICE
In the event that the fuse ils due
t ther
mal or mechanical abuse
,
it may be replaced by
opening the case and removing it
om th
e
spring clips in the uni
N
EV
OPEN
E
C
ASE
W
I
O
UT
D
I
SCO
NNE
IN
G TH
E SP
R
IN
T
F
RO
M
E PO
W
ER OUT
L
E
T
AN
D FR
O
M A
N
Y
OT
H
D
EVI
C
E TO
WH
I
CH
IT IS
C
ONNE
T
O
AV
O
I
D
SE
R
IOUS S
H
O
CK HAZ
A
RD
.
R
eplace the
fuse with a similar fuse of the same rating
,
to in
sure protection of the power supply and to pre
vent possible fire hazard. The rrect fuse rating
is identified on the exte
al lable on the under
side of the lower case.
15
COMPONENT PARTS IN THE
SPRINTER 40 PACKAGE
4
6
sC1
s
d
cs Cs8
e
CS1
c
)=1
�
j
I
ll
\
�
D
CS2
TR1
SW3
CS4
Lower plastic main case with
label
U per plastic main case with
nameplate
Plastic paper roll ver and cutter
Plastic paper release lever
Rubber feet
Power switch
Paper feed switch
Power printed circuit board
117 v 60 Hz Power rd
0 v 50 Hz Power rd
Slo-blo fuse
110/0 VAC 50-60 Hz 24 v
1.3 amp Power transrmer
Set of case screws
User instruction manual
User warranty card
CS1
CS2
CS3
CS4
CS5-CS8
SW2
SW3
PC2
PW1
PW2
FU1
TR1
SC1
IM1
IM2
REPLACING THE VLSI
CONTROLLE
In the event that the VLSI ntller is dam
aged by inrrect intercing or is being changed,
it may be replaced by opening the case and re
moving it om the 40 pin socke It should first
be loosened by carefully inserting a thin blade
sewdriver alteately under each end of the
chi until it can be lifted om the socke The
ins on the replacement unit should be carefully
checked to insure that they are correctly aligned,
bere inserting them into the socke The chip
should be oriented so that pin 1 (with the small
dot molded into the er) is nearest the left
ont er of the SPRINT.
Other maintenance requires laboratory ser
vice equipment and spare parts r the uni
Many dealers either oer this service or are
miliar with local service centers in your area. If
you cannot find satisctory local service, a ser
vice and warranty service center operated by the
manucturer is available. Consult the warranty
card enclosed r details.
16
COMPONENT PARTS FOR
EM 1840
40 COLUMN PRINTER
CONTR LLER BOARD
BOARD NAME
Z1
Z2
Z3
Z4
Z5-Z8
Z9
Z10
Z11
SY40F
74121
ULN2004
µA3CN
DS3654
7805
7808
TIPl 20
( r SPRINTER 40) VLSI Contr ller
One shot multivibrator
Transistor Array
Precision voltage regulator
Solenoid Driver
5 volt regulator
8 volt regulator
5 Amp Darlington Transistor
USAGE
Main printer ntller
Thermal dot timer
General drivers
V th power regulator
Thermal dot drivers
5 volt power regulator
8 volt power regulator
V th pass transistor
DESCRIPTION OF OMPONENT
C1
c2
C4
C5
C6
C8C10
C11
C12
1
fd12 volt ceramic disc
1000 fd 35 volt Radial Electrolytic
3300 fd 50
vt
Axial Electrolytic
100fd 16 volt Radial Electrolytic
.0015 fd ceramic disc
.1 µfd 12 volt ceramic disc
1000 fd 35 volt Radial Electrolytic
1 00 fd 16 volt Radial Electrolytic
47 fd 35 volt Radial Electrolytic
47fd16 volt Radial Electrolytic (early units only)
Reset timing cap
5 v lt raw DC capacitor
Main raw DC capacitor
5 volt storage cap
Input filter on 74121
Dot timing cap
V th storage capacitor
8 volt storage caps
3 supply cap
Motor smoothing cap
CR1
CR2
CR3
CR4
CR5
1 N750A
1N914
MR501
1N4001
1N973A
4. 7 volt 400 mwa Zenar Diode
Small Signal Diode
Motorola 100 volt 3 amp Diode
1 amp Diode
33 volt 400 mwa Zenar Diode
Serial Data clamp diode
Reset cap charge drain
V th power diode
5 volt power diode
Voltage protect µa3
17
18
BOARD NAME DESCRIPTION OF COMPONENT USAGE
R1
4700 ohm¼ wa resistor RS-232 input
R2
Meg ohm wa resistor Reset timing resistor
R3
470 ohm wa resistor ACK pullup
R4
470 ohm wa resistor BUSY pullup
5
5.6 Kohm¼ watt resistor V th voltage seing
R6
7 .2 Kohm wa resistor V th voltage seing
R7
Kohm wa resistor sets basic dot time
R8
470 ohm¼ wa resistor Dot OCK pullup
R9
470 ohm wa resistor Dot DATA pullup
R10
2 Kohm wa resistor a723 supply resistor
R11
.33 ohm 2 wa resistor current sense resistor
R12
Pi her 904 miniature pot 50 Kohm trims dot time
HS1-HS3
Heat Sink IERC LAE66A4 TO-220 heat sinks
P1
5-pin Berg Stick Connect to swtich PC
P2-P3
21-position Budy Ribbon Socket Printer Connectors
P4
6-position Budy Ribbon Socket Printer Connector
P5
40 pin low profile DIP Socket Controller socket
SW1
8 position solderable DIP switch Sets ntroller modes
Y1
2 Mhz Crystal Controller oscillator
SC1-SC4
8-32 '' long binder head sews printer to board
SCS-SC
6-32
%"
Hex Head Screws heat sinks
NU1-NU4
"
a /"
hi 8-32 inteally printer mounting
threaded swageable post
NU5NU10
6-32 Hex Nuts heat sinks mounting
PC1
Pnted Circuit Board 8" 7.1" ngle Sided FR-4
PR1
Olivei PU 1840/4 40 lumn thermal printer
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