Star Tech Journal

STAR*TEcH
February 1 996
Journal
i
II
'just the Facts, eh?"
John Liikala • Canadian Amusements • Burnaby, BC • Canada
DISPLAY SIMILARITIES
BETWEEN DATA EAST SIMPSONS AND WILLIAMS RoLLERGAMES
PROBLEM:
Attempt to repair a display using
another manufacturers product
that has a similar type pinball
display.
Observe both manufacturers
diagrams to determine if the in-
puts and circuitry are the same.
See figure 1 for Data East and fig-
ure 2 for Williams. Much to my
surprise the diagrams were the
same, so I proceeded to plug the
display board of the Simpsons
into the Williams Rollergames Pin-
ball. All the plugs matched per-
fectly, but when the pinball was
powered up, all the digits and
segments came on at the same
time on both 16 digit displays.
The pinball was shut down im-
Clll
aMNT .
RLltT
••
Figure 1
mediately. Next, I double
checked the diagrams again to
verify that they matched. A com-
ponent comparison was done
and it was found that the segment
buffers to drive the 7180 IC's
were different.
Williams uses MC14049 and
Data East uses MC14050-see fig-
ure 3 for IC comparison. By look-
ing at the IC comparison, you
will notice that 4049's are hex
buffer inverting while 4050's are
hex buffer non-inverting. That is
why all the digits and segments
came on immediately when it
was plugged into the Rollergames.
Now go back to the diagrams of
each display and look at figure
2. Williams shows hex buffers
non-inverting instead of invert-
ing, but do show the proper IC
number 4049. Make note of this
in your Rollergames manual in
case you do not have a CMOS
data manual in your shop.