OLYMPIA
ELECTRONIC
COMPACT
ELECTRONIC
COMPACT OPERATIONAL
DESCRIPTION
At
power
on
the
Power
Pack
transforms the
AC
line voltage and produces
the
following
DC
voltages
for
use
by
the
unit:
36V--12V--6V--SV
The transformer
T1
is
protected by a thermal fuse rated
at
125
degrees
C,
and a
1.25A delay fuse. _ .
Also
at
power
on all control lines
(CPU
Outputs} are set
to
logic
0.
Visible
indication
of
this
is
movement
of
the
carriage
to
the
left
stop.
After
reaching
the
full
left
position
the
carriage
is
moved, by
the
horizontal step
motor,
20 steps
(spaces}
to
the
right
which corresponds
to
the
default
setting
for
the
left
margin.
The
printwheel
and
ribbon
drive motors are positioned in
their
home
positions
at
this time
as
well.
Upon completion
of
the
preceeding steps, the Electronic Compact
will
remain in a
standby mode
awaiting
input
from
the keyboard. The Print Control Circuit Board
monitors
the
keyboard
for
such
input,
and upon its receipt,
will
cause
the
appropriate
output
to
be performed.
As
an example,
we
will
consider
the
unit's response
to
a keyboard
input
of
the
letter
M. When the M key
is
depressed
the
Print Control Circuit Board must
first
position
the
print
wheel
so
that
the
M spoke
is
directly in
front
of
the
hammer.
At
the
same
time
the ribbon
lift
mechanism must be activated
to
insure
the
ribbon
will
be placed
· between
the
print
wheel
and
the
paper.
Next, the necessary pr.int density must be determined. This
is
done
by varying
the
time
that
power
will
be applied
to
the
hammer fire solenoid. Three levels
of
print
density are possible and
the
appropriate one
is
selected by
the
CPU.
In
our
example,
the
longest
duration
hammer
fire
would
be effected due
to
the
width
and size
of
a
M.
After
the hammer
fire
solenoid
has
been energized
for
the
correct
amount
of
time
the
ribbon
lift
mechanism
will
be deenergized and
the
print
wheel
will
be returned
to
the
home position.
If
another
key had already been struck
the
print
wheel
would
move in the direction requiring the least movement
to
reach
the
next
location and
the
entire process
would
repeat itself
until
all characters which had been struck
at
the
keyboard were
printed.
The Print Control Circuit Board
will
continue
to
look
for
and respond
to
external and
internal inputs
until
the
unit
is
turned
off.
This concludes this module. You may
now
proceed
to
the
next page and complete
the
module questions.
When
finished, check
your
answers
with
the
feedback sheet
at
the
end
of
the
module.
2-3
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