Atari 400 Field Service Manual

The
four digit number
in the lower-right
corner of
the dispiay
screen
shows
the number
of tests
completed. In
addition, the
four
digit number above
it
in red
is
an error
counter which
indicates
the number
of times
the test has
failed.
If a
failure
occurs, a Red
1 is displayed
in the matrix,
this
shows
you the location of
the
errored
condition.
Table
3-1, Port Test
Legend
should
be used
to
determine the
cause
of the
failure
condition.
(Please
note,
a
blinking
1
at location
A
5 does not
indicate
a
failure.)
A
passing condition
for all
test is
indicated by
a in that
location
(i.e.,
CO or
D*). If
the failed
test
passes on
the next
pass, the 1
is replaced
by
a
0.
The
error counter
in
the
lower-right
corner
of the
screen increments
by
one for
each error
.
Verify
ROM
Test
This
test checks
the
Console's
ROMs
by
performing
checksum
tests
on them. By
entering
the
command
letter V
and
pressing RETURN
you
activate
this
test. The
screen
displays
a
checksum
for each ROM
and the
value
returned
by the MATH
PACK
together
with
a
PASS
or
FAIL
indicator
for each.
•
Upon
completion
of the
test, the
screen
displays VERIFY
ROM
and
either PASS
or FAIL
for
the
entire test.
This
test
can be
used
to pinpoint
which
ROM
is failing.
If
you suspect
a
ROM
is
intermittently
failing;
run
this test
for
15 or 20
minutes.
RAM
Test
This
automatically
uses
six
different
tests
to verify
the
operation
of the RAM
boards-
Enter the
command
letter
R
and press
RETURN
to begin
this
test.
A
prompt
is
returned
to the
screen
asking how
many
8K blocks
of
memory
to
check
(maximum
of
five).
Type
the
number
of memory
blocks
in the
unit
and
press RETURN.
(Remember
that,
1
equals
each
8K RAM
card and 2
equals
each
16K RAM.)
The
computer
displays
the
amount
of
RAM
it is testing.
If
the
amount
is not
what
you
entered,
one
of
two
conditions
may
exist:
1) the unit
does
not
contain
tne amount
of
memory
you
thought
it
did;
or,
2)
the
unit
has
defective RAM
card(s).
Figure
3-8
Ulustrates
a
defective
RAM
test
system
response
screen.
The
four digit
number
in white
at the
bottom
right
of
the
screen
indicates
the
number
of
tests
completed.
A
red
four
digit
number
directly
above this
is used
to
count the
number
of
failures.
ATARI
Home
Computer
3-1
1

Atari 400 Specifications

General

Manufacturer	Atari
Model	400
Type	Home Computer
Release Year	1979
CPU	MOS Technology 6502
CPU Speed	1.79 MHz
ROM	10 KB
Operating System	Atari OS
Keyboard	Membrane keyboard
RAM	8 KB (expandable to 48 KB)
Graphics	ANTIC and GTIA chips
Sound	4 channels
Display	RF output for connection to TV
Storage	Optional cassette tape drive or floppy disk drive
Ports	Cartridge
Display Resolution	320x192 (16 colors)