Atari 400

400 POWER-UP
CATASTROPHIC
FAILURES
AND
BASIC
OPERATIONS
BLACK/GREY
SCREEN
Is the
screen
black
or gray
lYES
NO
Check Power
Supply
Board
for:
Is there -5v
on J201
Pin 18
iGo
to
GREEN/YELLO
I
SCREEN,
Page
5-^
NO
YES
Check,
repair,
or
replace the
following:
CR206
-
CR209
-
replace 1N400I
type
diodes
with
1N5391
(C017988)
CR201
-
Ca203,
and
C2ai, C202.
and
C210
Is
there
>I2v an
J201. Pin
2
NOTE
1
See Table
5-1,
start
at the
top of it
and
trace
back
until clock
signal
appears,
indicating
which
component
has failed.
/
/
NO
YES
Check . repair
, or
replace the following;
Voltage
Regulator
(A20I),
CR204
and
C203
-
C205
Check
the CPU
Board for:
''
Clock Circuit
(see
NOTE
I)
Chip Reset
Voltages:
NO
Is there +5v
on
A302,
Pin 36 and
A303,
Pin 30
Repair
YES
Replace CTIA/GTIA
(A301)
Is a
clear
MEMO
PAD
on- the
screen
YES
Go
to
POWER-UF.
PART
II.
Page
5-8
NO
Go
to
C,
next page
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