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Anatomy Of A Pinball Machine (8 Parts You Need To Know)

Over the years, even though the internal construction of pinball machines changed considerably, many of the important components remain the same. From the essential coin operated switch which marks the start of play to the score display, there are lots of important parts in a pinball machine.

The 8 parts of a pinball machine that you need to know are:

  1. Coin operated switch
  2. Spring-loaded ball launcher
  3. Score display
  4. Bumpers
  5. Flippers
  6. Playfield
  7. Main circuit board
  8. Metal cabinet

Apart from the components listed above, there are a number of minor components that are used in a supporting role. These vary from machine to machine and are not indispensable, so their usage is minimal. Below, we take a look at all of these components in more detail.

8 Parts Of A Pinball Machine You Need To Know

1. Coin-Operated Switch

At the front of every pinball machine is a coin slot. Just below it is a coin-operated switch used to start a game. It gets triggered when a metal coin of a certain weight is inserted into the slot. Accurate calibration of this switch was very difficult. In the early days, people used to insert metal washers, so more sophisticated switches were devised to ensure that a real coin was used.

Current coin operated mechanisms can measure the weight of a coin very accurately with an error margin of one gram. Any coin over or under the pre-set weight is identified as a fake, and will be ejected back to the player and the game won’t start.

2. Spring-Loaded Ball Launcher

The spring-loaded ball launcher is a metal plunger with a spring around it located at the extreme right of the pinball machine. The plunger handle protrudes outside the metal cabinet. When a game starts, the machine places a steel ball in front of the plunger. The player pulls the plunger back as far as possible and then releases it.

The plunger powered by the compressed spring hits the ball onto the playing field to start play.

3. Score Display

The early pinball machines used an electromechanical display, where solenoids were used to drive a set of wheels with the digits 0 to 9 on them. Using a small set of gears, each wheel was interconnected to the wheels next to it so that the tens, hundreds, and thousands got carried over. The designs were very complex causing a high failure rate where the score would get stuck.

In the late seventies, when microprocessors and electronic seven-segment LEDs made an appearance, the mechanical displays were abandoned and replaced with LED displays. In the eighties, plasma displays were used.

4. Bumpers

Bumpers are mushroom-shaped knobs of different colors about two inches in diameter with rings around them near the top and a bulb inside. When the ball hits a bumper, the bulb switches on and a solenoid pulls the ring down to kick the ball away. At the same time, switches below the bumper turn on a loudspeaker to emit a loud thump or a bell might ring.

It’s common to see three to four bumpers positioned in a rectangular group separated by a few inches. When the ball gets trapped between them, the bumpers kick the ball back and forth to each other with their lights flashing and thump sounds galore. This adds to the overall enjoyment of the game, and it’s how you score a lot of points.

5. Flippers

Flipper arm length varies between one and a half inches to three inches, mounted on a steel pin about an inch high. They are made from hard plastic with a rubber outer layer to increase bounce. Each flipper is controlled by a circular plastic-covered switch on the side of the pinball machine and is powered by a dual-coil solenoid.

6. Playfield

Since the playfield is the largest area of the game where all the scoring takes place, manufacturers take a great deal of care in positioning various elements of the machine on it. careful placement of various elements on the playfield makes a big difference to the difficulty level and playability. This determines the popularity of the game.

The size of a standard pinball machine playfield varies with different manufacturers. Different sizes are used varying from 16.50 inches by 41.50 inches, to 28.5 inches by 51 inches. They’re housed in a metal cabinet with a 3/8-inch-thick glass sheet on top. The playfield is made from a plastic or plywood sheet with hinges on the side so that it can be lifted up for easy access.

The playfield is tilted at an angle of 6-8 degrees to ensure that the ball rolls naturally toward the lower end where the flippers are located, but not so fast that it’s unplayable. In many arcades, it was common practice to place a wooden plank under the rear legs of the pinball machine to increase the gradient. This made the game more difficult because the ball rolled faster toward the drain.

Ramps

Many pinball machines feature ramps. These are two walls about an inch high separated by a little more than the width of the ball. In between the walls is a ramp. The player has to hit the ball accurately with a good amount of force for the ball to roll up the ramp and go down on the other side. This is often linked to bonus points or an extra ball.

Holes

Holes are quite rare on pinball machines, and they never became very popular. A hole is a circular depression of width slightly more than the ball and an inch deep. If a ball rolls into it, the hole holds it for a few seconds before ejecting it out into play again and bonus points are awarded.

Dome

Some machines feature a target area on the playfield. When the ball passes over it, a dome pops up between the two flippers for a few minutes. As long as the dome is up, the center drain is blocked and the ball cannot exit the playfield.

Diverter Magnets

Magnets are embedded in many playfields to influence the direction of the ball. These are either permanent magnets or microprocessor-controlled electromagnets to make play more difficult as the score increases.

The Tilt Switch

Every pinball machine has a tilt switch to ensure that a player cannot shake or push the machine to gain an unfair advantage. There are times when the ball rolls straight down toward the center drain and out of reach of the flippers. In an effort to move the ball near one of the flippers to prevent losing it, the player can shake the machine to influence the ball’s direction.

If the tilt switch detects the machine is being shaken beyond a predetermined limit, it switches the tilt light on and in many cases ends the game, while some machines give a certain number of warnings first.

7. Main Circuit Board

Modern pinball machines are complete mini computers with their own set of logic and rules programmed into them. The main circuit board is fitted inside the metal cabinet, below the playfield. It has a microprocessor to carry out the logic and various processes of the machine, and a memory chip that has the instructions for the game programmed into it.

The circuit board connects to the playfield using multiple wires to each sensor and solenoid. Every bumper, hole, ramp, and element on the playfield has a built-in sensor that sends information back to the microprocessor.

Underneath The Playfield

So far, we’ve covered the operation of elements on the top of the playfield. Without an explanation of what happens on the underside of the playfield, however, it is difficult to appreciate the complexity of construction that goes into a pinball machine. The underside of the playfield is where the real anatomy of the pinball machine resides.

To facilitate repair, the playfield can swivel upwards on its hinges to reveal a complex maze of wiring interconnected with many other electrical devices. All the bulbs and solenoids are mounted as close as possible to their respective elements to keep things tidy.

The Process

As the player inserts a coin, the switch below the slot checks the weight. If it is recognized to be a valid coin, the machine starts a new game.

The score is reset to zero and a ball holder places the first ball (usually of five) in front of the spring-loaded ball launcher. Once the player launches the ball into the playfield, sensors built into the bumpers and playfield send a continuous stream of information back to the microprocessor about the ball’s position and objects it collides with.

Based on this information, the score is updated and other elements such as holes and domes can be activated. Once the ball rolls down the center drain, a sensor informs the microprocessor that a ball has been used up. This process repeats until all five balls have been used up, at which point the pinball machine flashes “Game Over.”

8. Metal Cabinet

The size of a standard pinball machine is typically 130 cm (51 inches) by 72 cm (28 inches). The height is 192 cm (76 inches). Modern pinball machines use a fraction of the power consumed by older machines and can run on very compact power supplies. The older glass sheet over the playfield has also given way to a clear plastic sheet.

The cabinet houses all the electronics, as well as the power supply. The score display is mounted in the upright rear of the cabinet. Mechanical bells and buzzers which were used in early machines were removed as more complex sounds can be generated by a microprocessor.

Other Important Pinball Terminology

In the early days of pinball, bumpers were called “Pop Bumpers”, and diverse bumpers made by different manufacturers got their own unique names. “Pop Bumpers” eventually became known as “Bumpers”, though terms like “Jet Bumpers,” “Jumper Bumpers,” and “Thumper Bumpers” were used to describe variations of the bumper. Flippers were first known as “flipper bumpers.”

The term “Backbox” is used to describe the vertical part of the pinball machine that housed the score display and artwork. You’ll likely come across many other variations on pinball terminology, but this guide to the basic anatomy of a pinball machine contains all of the main components you need to know about.

Final Thoughts

Many of the important components of a pinball machine are sacrosanct, despite the passage of many decades. Even though the internal construction of pinball machines has changed drastically, these parts’ overall functions within the context of the game remain largely the same.