Atari 400 Field Service Manual

ATARI
400/800
STAND ALONE
SYSTEM
TEST
REV
2
04
(Type
?
(C)
1981
FOR
HELP)
RAM:40K
TIA
NTSC
ROM:
MATH
NTSA:NTSA
Figure 3-2.
SALT
Header
i^.
If
a green/yellow
colored
screen is
returned,
this indicates
a
probable
OS ROM
malfunction.
Swap-out
the ROM
set with
a known
good
set
(make
certain
to test after
each ROM
is
replaced), this
allows
you to
pinpoint
the
defective
ROM.
If
the words,
SYSTEM
FAILURE
appear on the
television
screen,
this
indicates
that
the lower RAM
is not functioning.
When
this happens
and a *00
Computer
is under
test, turn
the POWER
off, swap-out
the
RAM
board with
a known
good
one and turn
the Power
on.
If
the
SALT
Header
is returned
to
the
screen, this indicates
a
probable
malfunction
in
the RAM
board which
was removed.
Refer
to the
DIAGNOSTIC
FLOWCHARTS,
Section
5 and 7
for
troubleshooting
procedures.
If
the
800 Computer
is
under test,
turn the POWER
off and swap-out
the
front RAM
Card with
a know
good
one. Place
the suspected
defective
RAM
CARD
into the
number 2 RAM
slot
(the third
slot
behind
the OS),
and turn
the
POWER
back on. This
lets
the SALT II
cartridge
troubleshoot
the
suspected RAM
CARD
later
in the
DIAGNOSTIC
FLOWCHARTS.
If RAM
and ROM
boards
have
been swapped
and the
condition
continues
to
persist, swap
the CPU
board with
a known
good board to
isolate
the
problems.
ATARI
Home
Computer
3-4

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)