Basic HTML Version
Flipper
Grounded
Switch••
Dedlcaled
Grounded
Switches
Orange-Brown
J205-1 U17-S
Left Coin Chute
01
Orang~ed
J20S-2 U17-7
Center
Coin Chute D2
Orange-Black
J20S-3 U17-11
Right Coin Chuta
03
Orange-YBllow
J20S-4 U17 -9
4111Coin Chula D4
Orange-Green
J205-6 Ul6-9
NonnoJ
I
Toot
FUlCIIon
FunctIon
Ser Credits Esc
OS
Orange-Blue
J205-7 Ul6-11
No"""
I
Tost
Ft..n CIIon
Fr. rdon
Vol Down Down
06
Orange·Violet
J20S-a Ul6-7
~~ I
~on
Vol Up Up
07
Orange-Gray
J20S-9 U16-5
No_
I
TMt
F L rdon
F1 ..n::IIon
Begin Test Enter 08
J2XX = CPU Board;
SWITCH MATRIX CIRCUIT
CPU BOARD PLAYFIELD
I
I
I
I
I
I
I
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I 470 pf
I
: Row (example)
~
:
L
~
ROW
SWITCH OPEN
SWITCH CLOSED
OFF
ON
The microprocessor is constantly strobing the column side of the switch. When point "A" on the column circuit
toggles low, the column side is active. When a switch closes, the row side of the circuit activates. The
"+"
input to
the LM339 drops below +5V, therefore, its output is low. Corresponding row and column switches must be low at the
same time for the switch to be considered closed by the microprocessor. When the switch opens, the
"+"
input to the
LM339 is above +5V, its output is high and the row is inactive.
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