How Pinball Flippers Work

Pinball flippers have worked on the same principal since they were invented: Energized coil pulls in a plunger which turns a flipper.  There have been a few innovations over the years:

1) Dual power coils and EOS switch.
2) Serial to parallel coils.
3) Computer controlled solid state flippers.

#1 allowed far more power to be applied initially than had been possible.  #2 combined with a capacitor allowed the EOS (End of Stroke) switches to last longer.   #3 sent only low power through the flipper and EOS switches so that they last far longer.

Brief History of Flipper Designs

* All EM pinball machines have Serial Coils.
* Early SS pinball machines continued to use the same Serial Coil design, with a few computer controls such as turning the flippers on / off.
* Somewhere around the middle of Williams System 7, a new design was introduced: Parallel Coil flippers (did Williams introduce parallel coils?).
* Starting with The Addams Family, Williams / Bally introduced the Fliptronics computer controlled solid state flippers.  Data East / Sega (and Stern) introduced their own design around the same time.

How To Tell Which You Have

The easiest way is to look at the coils.

All flipper coils (except computer controlled Data East / Sega / Stern) have two coils (or windings).  One is the power coil.  This is recognized by the thicker wire.  The power coil provides the high power needed to flip the pinball.  It is on for a short period of time.

Then the hold coil takes over.  This coil has a thinner wire and draws a small amount of the electrical power that the power coil does.

The first coil shown is a serial coil.  This is recognizable because there are two wires going to the center tab.

The second coil is a parallel coil.  This is recognizable because the two wires are going to one of the end tabs.  One wire goes to the power coil, the other to the hold coil.

The power coil goes from the left tab to the center tab.  The hold coil goes from the left tab to the right tab.

Identifying computer controlled solid state flippers requires a little research since all of these machines used the same serial coils.  The easiest is to consult the IPDB.  If you own a Williams / Bally WPC pinball machine, about 1992, Williams introduced the Fliptronics board.  Only The Addams Family had Fliptronics (or Fliptronics 1) through its entire run.

Williams / Bally then quickly introduced Fliptronics 2 in 9 machines.  All later WPC-S and WPC95 Williams / Bally pinball machines also used Fliptronics 2.

For Data East / Sega / Stern pinball machines, identifying computer controlled solid state flippers is much easier.  If the flipper coils have just two tabs, then they are computer controlled.

Next: Serial Coils