Ecn 110036 - Atari CX 5200 Field Service Manual

SOFTFIRE (TOP FIRE BUTTON) TROUBLESHOOTING
Be sure Pokey Adjust
Screen is displayed.
If not, press key 5
and then ST AR T.
When the top fire button
is pressed does pin
1 6 of A7 show 5V p-p?
Does output pin of
multiplexer pulse to
5V p-p when top fire
button is pressed?
(See Chart below)
Does input pin go
Low when top fire
button is pressed?
Defective
1 ) Cap
2 ) Port
3 ) Open Port to
Multiplexer
Repair or
.
CX5200 Field Service Manual
Yes
No
Yes
No
Yes
No
Replace.
Port
2
Note: Some 5200 2-port boards have pins 1 ,8,9, 1 0 and
jumpered together on the solder side of the
A7
of
PCB. Future PCB's
Do not add these jumpers to the 5200 2-port board.
4 A- l 9
Defective
1)
A7
3) A2
2) A8
Open output pin
to pin 1 6 of A7. ,
Defectiv e
Multiplexer
l )
2) A7
Multiplexer
A9
Pm 3
l ,2,�,5
A l O Pin
1 3
1 1 , 1 2 , 1 � , 1 5
will incorporate this jumper.
1 1
Changed by
E C N 110036
6 /2 1 /83