Atari 400 Field Service Manual

SECTION
5
WO
DIAGNOSTIC FLOWCHART
The
Diagnostic
Flowchart
is intended
to be
easy to use
and the
primary
aid when
troubleshooting
the ATARI
WO Computer
Console. Follow
the prompts
in
the order
presented.
When
a question
is asked,
follow the
line from
that box
which
best applies
to the unit's
situation.
The
flowchart
leaves
little to
chance,
it tells
you when
to
perform
a specific
test and when
to
replace
components.
Swap
Out
Procedure
At
many
places
in the
diagnostic
flowchart,
a box tells
you to
"swap-out"
a chip
or a
number
of chips
in
a particular
order.
The
"swap-out"
instruction
means
that you
should
replace
the
indicated
components
(one at
a time)
with
a known
good component
of the
same
type.
The
400 should
then
be tested with
the new,
known-good
component
in
place
to see
whether
the
"swap-out"
solved the
problem
being
checked.
If
the swap-
out did
not
fix the
problem,
the
known-good
component
should
be removed,
and the
original
component
reinserted.
In
this way,
you avoid
needlessly
replacing
good
components.
CAUTION:
Extreme
care
shouid
be taken
when
handling
the
integrated
circuit,
chips.
They
are
all
v«3r
sensitive
to
static
electricity
and
can easily be
damaged
by
careless handling.
Always
keep
the chips
in
their
plastic
carrier
tubes
or
on conductive
foam when
not
handling
them.
Make
certain
you
are well
grounded when
handling
the
chips. Atari
strongly
recommends
that
you wear
a
conductive
grounding
band
(which ties
from
yow
arm
to
ground)
when
handling
the
chips.
Thediijw
are also
susceptible
to
damage
from
stress when
being
removed
from
or
inserted
into
the
sockets.
Always
use
a
chip-puUer
when
removing
the
chips.
Do
not
pry
the
chip
out
with
a screwdriver
or
any other
tool.
Failure
to follow
the
above
guidlines
results
in
unusally
high
chip
failure
rates
and
extra
expense.
ATARI
Home
Computer
5-1

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)