Display:
The
Apple
Computer outputs a composite
video
signal (composite
of sync and video infor-
mation) which
can
be
applied to
any
standard
raster-scan
type
video display
monitor. The
out-
put
level
is
adjustable with the
potentiometer
located near
the
video output Molex connector,
J2.
The additional two
outside
pins
on the
Molex
con-
nector
supply
+5and+12
volts, to be
used
in
future
Apple
accessories.
The
composite video
signal
can also
be
modulated at the proper RF
frequency,
with
an inexpensive commercially
available
device
,
and applied
to the
antenna terminals of
a home
television receiver. Since
the
character
format
is 40 characters
/
line, all television
receivers
will have
the
necessary
bandwidth
to display
the
entire
40 characters.
Two large
manufacturers
of
video display monitors,
which connect
directly
with the Apple Computer, are
Motorola and
Ball.
The
mating
four—pin Molex connector
is
provided.
equivalent
{
28VCT at 1
amp).
Simply
wire
the
secondaries
to
the mating
six-pin
Molex
connector
supplied,
and wire
the primaries
in parallel,
as
shown
in
the
schematic diagram
(power
supply
section,
Dwg.No.
00101,
sheet 3 of
3.
TEST PROGRAM
After
attaching the keyboard,
display,
and
AC power
sources, you
can
try a
simple
program
to test
if
your
system
and the
attachments
are
functioning
together properly.
While
it
does
not
test
many
possible
areas
of the
microprocessor
system,
the test
program
will
test for
the
correct
attachment
of the keyboard,
display, and
power
supplies.
FIRST:
Hit the
RESET
button
to
enter
the
system
monitor.
A
backslash
should be
displayed,
and
the
cursor should drop
to
the
next
line.
AC Power Sources:
Two
incoming AC power
sources
are re-
quired for operation:
8 to 10
VAC
(RMS) at 3 amps,
and
28
VAC
(RMS)
Center-Tapped
at
lamp.
These
AC
supplies
enter
the system at the Molex
con-
nector, Jl.
The 8 to 10 volts
AC
provides the raw
AC
for the
+5
volt supply,
while
the 28 VCT
sup-
plies
the raw
AC
for the +12 and
—12
volt supplies,
and the
-5V supply
is derived from
the -12V
reg-
ulated output.
The board, as supplied,
requires
no
more
than
1. 5
amps DC from
the
+5V
supply,
while the
regulator is
capable
of supplying 3 amps. The
remaining 1.5
amps
DC
from
the +5V supply is
available for user hardware
expansion
(provided
suitable transformer
ratings
are employed).
A
suitable source
of
the
raw AC
voltages
required, are two commercially
available
trans-
formers;
Stancor P/N
P-8380
or
equivalent
(8
to
10 volts at
3
amps), and Stancor
P/N P-8667
or
SECOND:
Type-
:
A9
b b AA
b
20
b
EF
b FF b
E8
b
8A
b 4C b 2
b
(RET)
(0
is
a
zero,
NOT an alpha "O";
b means
blank or
space;
and
(RET)
hit the
"return"
key
on
the
keyboard)
THIRD:
Type-
.
A
(RET)
(This should
print
out, on the display,
the
program
you
have
just
entered.
)
FOURTH:
Type- R(RET)
(R
means run
the
program.)
THE
PROGRAM
SHOULD THEN
PRINT
OUT
ON THE
DISPLAY A CONTINUOUS
STREAM
OF ASCII
CHARACTERS.
TO STOP THE
PRO-
GRAM AND
RETURN
TO
THE
SYSTEM MONITOR,
HIT THE
"RESET"
BUTTON. TO
RUN AGAIN,
TYPE
:
R (RET).
-2-
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