Star Tech Journal

Data East Speed Buggy Sensor PCB
Phillip G. Stewart, Customer Service
Data East USA, Inc.
San Jose, California
SUBJECT
If the optical devices on the IME sensor PCB are
Data East's Service Department has compiled
the following information on the sensor PCBs
used in the accelerator, brake and steering as-
semblies. These PCBs are simple in design and
have a low failure rate, however, your feedback
and requests has prompted us to compile this
information.
not aimed perfectly at one another, the output
signal's LO portion begins to rise above ground
potential (see Figure 1), causing the logic PCB to
ignore the signal.
SENSOR PCB
The sensor PCB used in the upright model
steering assembly is manufactured by IME in
Italy, whereas the accelerator PCB is supplied by
the game's creator, Tatsumi. The three monitor
cockpit version of Speed Buggy utilizes the
Tatsumi produced sensor PCBs exclusively. It
has been our experience that the Tatsumi sensor
PCB is relatively trouble free, whereas the IME
PCB has had a slightly higher failure rate.
STEERING CONTROL
• One of the most common problems experienced
is with losing steering control on the upright
model caused by mis-alignment or failure of the
optical devices used on the sensor PCB. the
input circuitry of the logic PCB requires a perfect
signal from the sensor PCB. This signal is ba-
sically a square wave, but the LO half of the
signal must reach ground potential (O vdc) for
proper operation (see Figure 1).
Jufl ~~:-: ~tn
GCOD
Figure 1
Test Point
1
2
3
4
5
6
Sensor Clear
Sensor Blocked
1.2 vdc
0 vdc
5.0 vdc
1.2 vdc
0 vdc
5 vdc
1.2 vdc
4.5 vdc
0 vdc
1.2 vdc
4.5vdc
0 vdc
NOTES
1. Sensor Clear means that there is no object
between the LED and the photo-transistor.
Sensor Blocked means that an object has been
inserted between the LED and the photo-tran-
sistor. A business card or any flat card stock is
suitable for this purpose.
Ol>T
0-
OUT
b
GND