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So I went to an arcade in Colorado Springs recently and they had a bunch of old Pinball machines from the 1960's, which once playing them made me wonder what made them work considering most of these were made before the invention of transistors, better yet microprocessors. I mean, if they were released later I could see that they could've maybe used transistors, but that would have been huge and probably really expensive, I mean too expensive for the average person who ran an arcade back in the day. Were logic chips available back in the day? They might have been because Pong from 1972 ran off of discrete logic chips, and I'm pretty sure that was the standard until Gun Fight in 1975. I'm pretty sure that most of the pinball machines I saw were from either the late end of the 60's or early 70's because most of them used vacuum fluorescent display for the scoreboard, but a few still used paper rolls (Like the one used on the c64 tape deck)

They had 74-series chips by the mid-1960s and could build bigger things out of them. Don't know if they would have been used for Pinball machines though.
Transistors were invented in the 20s, and Nobel Prizes were awarded for them in the 50s, so they were easily available in the 60s.

And in the beginning, there were Relays. Coil of wire and a little piece of iron, and you have an electronically controlled switch.

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Here come the fortune cookies! Here come the fortune cookies! They're wearing paper hats!

I think that's sort of true, but I think the modern transistor is usually considered to have been invented in 1947.

The transistor radio became a hit in the late 50s, so they were clearly into mass production by then.

Early pinball machines were all ladder logic.

Pinball machines from before the late 70s are typically described as "electromechanical" (while the electronic tables introduced then are commonly referred to as "solid state"), you can tell how they work just by looking below the playfield. Good luck sorting everything out though!



Needless to say, adding electronic software to pinball tables introduced a much higher potential for complex rulesets, keeping states between ball across several players, and overall progression throughout the entire game, and as such even though the pre-70s tables will always be considered classics, they can never compare to the masterpieces created afterwards.

Let's all take a step back.

The ball is metal for a reason.
When the ball touches for example a bumper, it completes an electrical circuit to a solenoid coil that then drives an actuator to push the ball away, as one example. The completion of the circuit might also go to another coil and actuator that increments up the score and/or a relay that flashes a light.

As you see the ball moving around the table, just think of all the circuits that it completes when it touches something.

When a ball falls into the bottom gutter, there's electrical conduction there to drive some mechanism to deliver the next ball.

Just think about what even a coin insertion does, which would give a pulse to reset the elements on the table, the score, and the mechanism to deliver the 3 balls.

That isn't strictly true - many tables used mechanical switches which were activated when the ball struck them, and in that case the advantage of metal is its higher weight and greater inertia.
Steel also happens to be magnetic, but not many tables took advantage of that...


Minor nitpick: back in those days, each game typically gave you 5 balls, not 3.

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We have some 60s-era machines that you have to manually pump the next ball into the plunger well. As a kid, I'd just pump all 5 in at once and just do a crazy multiball, but then I got better at it and started playing "correctly". If you look next to the plunger, there's a window where you see all of the spent balls, and you also see two levers that balls #4 and #5 sit on to tell the machinery that the game is over.

I don't recall seeing any bare metal contacts, most bumpers have a rubber belt around them, and the ball will mostly roll over pressure pads, or into wells that have buttons and kickers in them. Maybe the large mushroom-shaped bumpers use the ball to complete a circuit?

I always liked the "gravity well" idea on 3D Space Cadet Pinball, and kinda wondered if anything like that was ever implemented in a physical machine, though I'd also assumed having such a strong electromagnet would be hazardous to nearby things in its environment.

I've never seen a pinball table using the ball's metal to complete a circuit. While I guess it's technically possible (but pretty unreliable), I assume this is just speculation on whicker's part.
Every pinball game, dating back to when they first started to apply some sort of logic, uses mechanical switches. In fact even today almost every part of a pinball table not related to software is entirely mechanical, except it's being controlled via an electronic pcb. The switches and solenoids used to register the ball and making things move are nearly the same.

The actual reason the balls are metal is because the cheapest way to procure high quality high density balls was simply reusing regular ball bearings, removing the need to have a dedicated production run of pinballs. There are several examples of tables using special non-metal balss, though, such as Twiligh Zone's ceramic ball which results in completely different physics.

A little off-topic, but I wonder if this has ever been done before:

http://www.myabandonware.com/media/scre ... ball_7.jpg

A double-sided pinball machine.

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Ruling the World One Bean™ at a Time...

The term of art for that form is known as a "head-to-head pinball" machine; examples include Gottlieb's Challenger in 1971 and Williams's Joust in 1983.

Man; in my mind, I had a gravity-defying pinball machine.

Well, here's one with an actual gravity well:

https://youtu.be/jX0sfsi_zxo?t=1m52s
(Stern Orbitor 1)

Disappointed it's not magnetic, but I love how the ball can return underneath one of the paddles.