Atari 400 Field Service Manual

NO
Are C164
(.luf).
C179
(.luf). R161
(ISK)
or R166 (6.8K}
open
YES
400 TONE TEST (cont)
Repair
and retest
YES
Repair
and retest
NO
Are
C184
(.OOIuf)
or
R170
(4.7K) shorted
or
open
.xss.
Repair
and
reteet
NO
Can
you verify
the
following
:
1) 4.SMHZ
osciUation
by connecting
a
scope
to the
emitter
of
Q105
2) A
sine wave
^
Z.l
centimetera
9
.lua/Dlv
and
20mV/Dlv
which
equals
s
4.
3MHz
3)
Can
you adjust
LlOl
to
equal
4.SMHz
YES Verify
input to
Audio
Mixer
by connecting
scope
(
.SmS/Div,
5mV/Div)
to
collector
of
Q106
Are
wavefoma
same
as AlOl.
Pin
37 (except
wave-
form
is rounded,
not
square)
NO
Repair
and retest
No
Return
to START,
Page
5-24
YES
Is there
output
on
LX18
(use
scope
(.5mS/Div,50mV/Div)
NO
Replace
Q106 and
retest
YES
Go to
next
page I
ATARI
Home
Computer
5-26

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)