Atari 400 Field Service Manual

Keyboard Test
This
test verifies the
Console's
ability
to accurately
accept
operator
input from
the
keyboard.
By
pressing
the command letter
K and RETURN,
this
test
is
activated.
You
are to
press
each of the keys
EXCEPT,
the SPACE BAR,
CNTL
and both
SHIFT keys.
Each
letter
pressed
is returned
to the display
screen. Once
this
portion
of the test is
completed,
hold
down the
CNTL key
and press
the lette
r
A.
The
letters CTRL
are
returned
to the
screen. Now,
hold down
the
left
SHIFT
key
and
press A. The word
SHIFT
is re
turned to
the screen. By
holding
down the
right SHIFT
key
and pressing A,
the word
SHIFT
is again
returned to
the display
screen. Finally,
press the SPACE
BAR
and then,
RETURN.
The
words KEYBOARD
PASS
or KEYBOARD
FAIL
appear
on the
screen below
the
keyboard
test. If the SALT
II
cartridge
detects
any key
failures
during
the test,
the
defective keys
appear
on the
screen in
the color
red.
Switch
Test
This
test
verifies
the
proper
operation
of the
four
Console
Switches (START,
SELECT,
OPTION,
and SYSTEM
RESET).
By
pressing
the
command
letter
S
and pressing
RETURN,
this test
is activated.
Press
the
console
switches
in
the following
order:
1)
START;
2)
SELECT:
3)
OPTION;
and
^f)
SYSTEM
RESET.
Upon
pressing
SYSTEM
RESET,
either
PASS
or FAIL
is
returned
to the
screen.
Tone
Test
This
test
verifies
the
ability
of the POKEY
to
generate four
sound
registers
through
its
sound
generation
circuits.
Press
the
command
letter T
and RETURN.
A
prompt
(question)
is
returned
to
the
screen
asking
you
which
register
you want
to test.
You
must
press
the key
with
the
number
of the
register
you want
to test
(1, 2, 3, or *) and
then
press
RETURN-
The
test
generates
eight
tones
in
descending
order.
The
first
three tones
are very
nigh
and may
be
inaudible
to
some
people.
Each
tone begins
at
maximum
volume
and fades
to
minimum
volume.
You
must
enter
the
command
letter
before
each register
test.
Make
certain
to
test
all four
sound
registers.
NOTE:
The
television
volume
control
may have
to be
turned
up in
order
for
you
to hear
the
first three
tones.
ATARI
Home
Computer
3-9

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)