Atari 400 Field Service Manual

KEYBOARD
(contl
Troubleshoot
. using
foilowing
information
and
Keyboard
achematic.
Page 5-3$
TYPICAL
KEYBOARD
OUTPUT
Sample
oaade from
Z104,
Pin
U '^th
W
key depressed.
SCOPE:
rTT/DIV,.5oiS/DIV
SYNC ;
CHI,
Trigger
ltJ
TYPICAL
DECODER
OUTPUT
Sampie
made
from
Z104.
Pin 3
with
W
key
depressed
SCOPE
;
TTV/DIV,
.2mS/DIV
SYNC
;
CHI,
*
Trigger
nn
Pass
JCSS.
Go to
TONE
TEST,
Page
5-24
MO
CaU
ATARI
Tech
Une
Specialist
Inside
California
(800) 672-1466
Outside
California
(800) 538-1535
(800) 538-1536
ATARI
Home
Computer
5-23

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)