Atari 400 Field Service Manual

Display Options
This function, which
is not
a
test,
displays a diagnostic matrix
when
used in
conjunction with
either the
RAM TEST
or
the
PORT TEST. It
allows
you to identify
which ROM
chip has failed when
used with the VERIFY
ROM TEST.
By
pressing command
letter D and RETURN
you access this function. The
screen
returns the prompt
to enter a test format, To
use the PASS/FAIL
indicator,
enter the
command letter P
and press RETURN. To
display
the ERROR TABLE,
enter the
command
letter E and press RETURN.
For the
following PORT, VERIFY
ROM,
and
RAM TESTs,
press
the
command letter
E and RETURN. The
screen prompts
you to
enter the command
letter S for
a single test, or
C for continuous testing.
You
are
now
ready
for the three tests. To
terminate
any of the following
three tests,
press the SPACE
BAR.
NOTE; The RAM
test
completes its
current test
before
stopping.
Port
Test
This
test verifies
the ability
of the computer
system
to communicate
through
the
controller jacks
and the
peripheral
I/O
port.
The
command
letter P
and RETURN
activates
this test.
Make
certain that the
Peripheral
Jumpers
are in place,
and press RETURN
again.
Figure
3-7
illustrates
the
Port
Test Matrix
Display.
This
figure
is a biack
and
white
representation
of a color
television
screen.
The
zeros should be
a
blue
tint.
0000
0000
0000
0000
210
000
000
0000
8888
0000
0000
0000
0000
0000
PORT
TEST
ERROR
COUNTER
TEST
COUNTER
Figure 3-7.
Port
Test
Screen
ATARI
Home
Computer
3-10

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)