Atari 400

SECTION
6
SYMPTOM
CHECKLIST
The
Symptom
Checklist
is designed
to assist
the
experience
technician
arrive
at a
rapid diagnosis
for
problems.
The
checklist
is
not intended
to
replace
the
Diagnostic
Flowchart
as the
primary
troubleshooting
guide, but
rather,
to
supplement
the
flowchart.
Each
symptom
is
accompanied
by
some
possible
causes
and the
best
point to
enter
the
Diagnostic
Flowchart
to
locate
the
problem.
Symptom
Possible
Cause
Diagram
Entry
Point
Snowy
Screen
Black/Gray
Screen
Green/Yeilow
Screen
Solid
Blue
Screen
No
Color
or
Bad
Color
Bars
with
SALT
11
No
Color
Bars
on TIA
Test
SW
Box, AC
Adaptor
CH.
Select SW,
Modulator
Adjustment, RF
Cable
Damage
Verify -t-SV,
-*V
& +12V
Power
Supplies,
CR20
1-209,
C201-205,
C210, A201,
A302,
A303,
A301,
A103,
Alll,
Z103-Z105,
Q103-4, XlOl
2103-5, A03,
Z303
& *
all
on
ROM
Board
A101,Q107,
XlOl
R309
Adjust,
A301-2on
CPU
Board;
Alll,
Ql 07
on
Mainboard,
XlOl,
Q103,
QIO*
Modulator
Adjustment
A301
on CPU
Board
AA
400, Page
5-3
SOO,
Page
7-3
BB
400, Page
5-4
800, Page
7-4
CC
400, Page
5-6
800, Page
7-6
DD
400, Page
5-7
800, Page
7-7
E£
400, Page
5-9
800, Page
7-9
FF
400, Page
5-12
800, Page
7-12
GG
400, Page 5-12
800, Page
7-12
ATARI
Home
Computer
6-1