Play Meter

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BUSH: Poor design or inadequate design.
PLA Y METER: Could you give me a couple of
examples?
BUSH: I hate to point fingers, but yes, I can give you
examples. When Midway came out with the Gun
Fight machines, they used a 560 ohm resistor in the
circuit that makes the arms of the men move up and
down, the photo-optical isolator circuit. This is the
bumper circuit. between the control panel and the
computer. They used a 560 ohm resistor and the
thing started burning up a month after the games
were brand new. So we got them and looked at
them and said, "Ah ha. What's wrong is that the
resistors are too small." What they should have
used probably was an 800 or 840 or 860 ohm
resistor, but to be safe we put in 1000 ohm
resistors. We just damn near doubled the
resistance value.
A year later, when they came out with Night
Driver, a much later game, they were using 1000
ohm resistors. It's got the same circuit, but they
had gone from a 560 ohm resistor to a 1000 ohm
resistor. You'd be amazed at how many operators
had trouble with that arm movement problem,
could never get it fixed but kept replacing the 560
ohm resistor and the photo-optical isolator. And at
the time photo-optical isolators were hard to
get-we were having to pay maybe $13.00 apiece
for them from State Music. We've got a better
supply of them now, and we're buying them for
three bucks apiece. But back then, you had the
hottest game to come down the pike in ten years,
right? It plays for a month and then goes down. It
earns $200 a week, then up and dies. Guys were
sick about it, and it was strictly a design problem.
But I don't want to point fingers just at
Midway-I think they do a great job. Let me give
you another example. Allied Leisure. They
designed that arcade piece, the ski machine, where
you stand on it and listen to Alpine music and move
your feet back and forth. They drew a schematic
and published the damn thing and one place it said,
"This is a four -way bridge rectifier," (and they
drew a picture of it). And it was not a four-way
bridge rectifier. It just wasn't. Whoever drew it,
whoever designed it, just did not know what he was
doing.
Now, I personally don't know a four-way bridge
rectifier from the Golden Gate Bridge, but we've
got help here that does. And one of our guys looked
at the schematic and said, "Hey, that's wrong." And
I said, "Surely not. This is a major manufacturer.
Surely they wouldn't make that kind of mistake."
And the guy said, "Yeah. Look: here's what a
four -way bridge rectifier looks like, and here's what
they did. And that's not the same as that." So we
sat down and we wrote a letter to Allied and said,
"Hey, did you print this wrong or did you make it
wrong after you designed it right or did you really
in fact design it wrong? Surely you didn't do that."
And they wrote us back a letter and said, "Yes,
you're right. We did it. We're sorry."
PLAY METER: Do you find though that the games
of today are generally more reliable than the older
ones?
52
BUSH: Some of them. A manufacturer has got an
altogether different set of problems from anybody
else. He's got different problems from the service
business he's got different problems from the
magazine business. The manufacturers have
production deadlines just like you've got publishing
deadlines. They've got a game on the drawing
board and they've got a plant that's going to become
idle at the end of three weeks unless they're ready
to build something else, right? So they've got that
engineer back there humping to get that machine
designed so that they can begin building it, so that
they don't have to layoff all those production
workers. So the fact that they sometimes rush into
something to keep the line going, to keep up
production, doesn't really surprise me. In fact, it
surprises me that they don't make more mistakes,
because when you're designing a game and
putting it all together, with all the different areas of
expertise you've got to have to put one together,
you're bound to have problems. They do damn well,
I think.
PLA Y METER: Most manufacturers do put out
prototype games though, and they should work
through most of the problems with the prototype,
don't you think?
BUSH: What about P.S.E.'s Bazooka, for example?
That thing was a piece of junk when it first came
out. Everything just fell apart and broke on it.
Then they went back and completely redesigned
the circuitry, redesigned the cabinetry. It looks
much the same from the outside, but it's an
altogether different game now.
PLAY METER: Are there any methods of
preventive maintenance that can be used in
solid-state equipment? You mentioned putting the
1000 ohm resistor in place of a 560 ohm resistor in
Gun Fight. Are there any other forms of preventive
maintenance that you can think of to keep the
equipment operating?
BUSH: Power supplies are very important. A good
deal of the time, the power supply is the problem or
at least the power supply causes the problem. TTL
logic is designed to run on five volts, plus or minus
five per cent, so it'll run from 4.75 to 5.25 volts. And
that is not very much differential. It takes a damn
good voltmeter to get that kind of accuracy. The
average pinball mechanic has never seen that kind
of voltmeter- it's a three hundred dollar instru-
ment. Still that's what he ought to have, because if
he lets that thing run at 5.4 volts, it'll probably do a
few things wrong, but it'll also burn that board up
in half its normal life-time. That five volts is very,
very critical.
PLA Y METER: So if you had to recommend one
piece of test equipment to get, it would be a
voltmeter that registered that accurately.
PLAY METER: Yes, a good one per cent
voltmeter.
PLAY METER: Still, even if today's games are
generally more reliable, and even if preventive
maintenance is practiced, there are going to be
some breakdowns. Is the actual repair of these
games becoming more or less complicated?
BUSH: It's becoming more and more complicated,