Atari 400 Field Service Manual

400
FOWER-UP
CATASTROPHIC
FAILURES AND
BASIC OPERATIONS
SNOWY
SCREEN
Is tha scre«n
snowy
YES
NO
Go to Slack/ Gray
Screen,
Page 5-4
Check, adjust, or
replace AC
power
aciaptor,
channel
select switch
and
TV switch
box
Is
a clear MEMO
PAD
on the
screen
NO
Does
Power
Supply
Board. J201. Pins
3.
6, and 7,
have
+5v
YES'
NO I
Is
there
a good
ground
connection
at
Pin
1
of RF Module
Repair YES,
Is
a clear
MEMO
PAD
on the
screen
NO
YES
Go to
POWER-UP,
PART
II. Pa^e 5-8
YES
Is the RF Module
mistuned or
defective
NO
Go
to
Black/ Gray
Screen. Page
5-4
YES
I
Go to
POWER-UP:
PART II, Page 5-8
MO Check
.
repair
.
or
replace the
following:
CR206-CR209. replace
IN4001
type
diodes
with IN5391
(C017988)
Does voltage reg-
ulator (A202)
have
+5v
Check
C208.
C209,
R203, and S202
-
replace if
defective
Is a clear
MEMO PAD
on the
screen
NO
YES
ATARI
Home
Computer
5-3

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)