Star Tech Journal

December 1 997
STAR-.-TECH JOURNAL
PIAYFIELD Sw1TcH OPTO
''LoNc-HoP" BoARDs
T EAM SEGA PINBALL
Joe Blackwell, Eric Winston, Doug Lemons,Jay Alfer
Sega Pinball, Melrose Park, Illinois
PLAYFIELD SWITCH OPTO
BOARDS THEORY OF OPERATION
The light falling on LED ( CRl)
generates a voltage which is ap-
plied to the input (Pin-2) of the
LM311 Comparator (Ul). Rl
bleeds off excess charge. At
about a volt input from LED
(CRl) the Comparator (Ul)
trips & drives either Q,1 ( during
switch line strobes) or the indi-
cator LED (CR2) (in between
strobes). If a switch line is being
strobed, the emitter of Q,1 drops
to the saturation voltage of the
Switch Line Driver, about .3v.
This plus the . 7 volt drop on the
base give a 1 v forward bias volt-
age to Q,1, which is lower than
the 1.7v drop on LED (CR2) so
the current flows through the
Transistor during strobes. This
drives Q,1 on and makes the
switch. If the strobe line is high,
then the 1. 7v path through LED
(CR2) is lower than Q,l's bias
voltage so current flows through
LED ( CR2) and the indicator
lights. D 1 prevents reverse
One of the things we have always
preached in our Service Depart-
ment is that "communication is
the key to success." So whenever
we have something "new" or
unique in our games, we try to
get it out to YOU, before YOU
get to it.
We have introduced this New
OPTO Board combination
(Transmitter, 520-5082-00, and
Receiver, 520-5083-01) in our
last 2 games ID4: Independence
Day and The X-Files and our
Current Game, Starship Troopers.
In ID4 the OPTO Board com-
binations were used as Playfield
Switches to recognize the pinball
approaching the Alien Head. In
X-Files the OPTO Board com-
binations were used as Playfield
Switches to recognize the pinball
approaching the File Cabinet. In
Starship Troopers ( Current Game)
the OPTO Board combina-
tions are being used as Playfield
Switches to recognize the Left &
the Right Orbit Shots.
r---------------T---------------------------------------------------------------
520-5082-00 520-5083-01 ==• Emitting Light
+5v
+5v
:
:
Transmitter
I
I
I
: +5v .
Receiver
+sv
CR1
LED
MT5000UR
1
I
:
CN1
+ V
1
:RED
I
I
I
-:-
R1
•BLK 2
1M O
R3
47K O
.1uf. 25v
CN1
D1
1N914
1 RED
(+SV)
~ - - - - I 2 WHT/XXX
R2
(Switch Row/
330KQ
GND
C2
Return•)
I
- - - - - - < 3 GRN/XXX
C1
1uf, 25v
(Switch COii
Drive·)
4 BLK
(Ground)
RECEIVER
TRANSMITTER
SIDEVIEW
520-5082-00 (TRANS)
Com~nent
Side (Beigej
CN1
520-5083-01 (REC)
Component
Side (Beige I
bleed, R2 and R3 form the volt-
age divider for the trip point, R4
is a current limiter for both Q,1
and CR2, Cl and C2 are gen-
eral noise-filter caps.
Any questions or comments,
please call us in Tech Support,
800-542-5377.