Ram Test 3A-8; Pokey Adjust Test 3A-9; Pokey - Atari CX 5200 Field Service Manual

POKEY
(PORT) TEST
•
Purpose:
To
determine any
port
line
failures
and confirm the correct
operation
of
the
POKEY
chip.
•
Procedure: Press key
5
followed by
START.
•
Format:
When
you
press
the
keys
listed in
the
first
column below,
the
numbers and
letters in the
second
column
should appear on the screen
in
the
KB
column:
KEY
KB
Readings
1 1
2 2
3 3
4 4
5
5
6 6
7 7
8
8
9
9
#
D
0 0
*
E
START A
PAUSE
B
RESET C
If
the
keys do
not
register cc
TROUBLESHOOTING,
page 4A-22.
Press the
bottom
fire
button.
The
POKEY ADJUST
screen
should disappear.
If it
doesn't
proceed
to
page 3A-9.
Press
key
5
followed by
START,
again bringing
the
POKEY
ADJUST
pattern
to the screen.
Unplug
the controller
from Port
1
and
insert
it
into
Port
2.
Repeat Step
2.
RAM
TEST
NOTE: When
using the
1.1
Diagnostic
Cartridge
to test
the
2-PORT
5200, the
KB
Readings may
appear
to
the right of
any
of
the four ports
listed
on the screen,
besides the port
you
are
testing.
They
must, however, appear to the right of the
port
you
are testing for the
test to
be
valid.
:orrectly
when
pressed,
proceed
to
KEYBOARD
Initialization for
RAM
Test
•
Purpose:
To
set the
5200
up for
a loop
test to fully
check
the
RAM
(A18-
A25).
•
Procedure: Press
key
9
followed by
START.
Then
press
key
2
followed by
START.
Again
press
key
2
followed by
START.
DISPLAY
ERRORS CONTINUOUS
TEST
appears
in
the
green band on
the
RAM
Test Procedure
•
Purpose:
To
test
the functioning of the
16K
RAM
chips.
•
Procedure: Press key
7
followed by
START.
CX5200
Field
Service
Manual
3A-8