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Flipper Upgrade Information
NOTICE: For some very important information, please read the Technical Article Notice and Disclaimer, found on our Technical Articles Index page before performing any of the work described below. The information given below assumes you have read the Notice and Disclaimer first.

New replacement parts for most older-model pinball games can be difficult or impossible to find anymore, since most of the original manufacturers have been out of business for several decades and new replacement parts simply aren't available anymore.

One alternative to the difficult task of trying to repair or rebuild the flippers on your older-model pinball machine is to consider upgrading the entire flipper assemblies to a modern design. There are a few benefits to this upgrade:
  1. Newer style flipper mechanisms are usually a much better design than older units and will perform and last longer.
  2. Replacement parts for newer mechanisms are usually readily-available in the current market and can be easily and inexpensively obtained.
One upgrade we recommend is replacing your original flipper assemblies with later-model Bally/Williams mechanisms- such as the type used on Williams games from about 1986-1999, and Bally games from approx. 1988-1999.

Full flipper assemblies (less coil) can be found and ordered on our General Parts & Supplies page in the "Flipper Parts" section. Flipper assemblies are available in both left and right side units, and are available for older model games (using high voltage EOS switch) and later model games (using low voltage EOS switch).


Flipper Coil Mounting:

When using the later-model units, you can either keep and re-use your old flipper coils, or you can purchase new coils- either in the old original style, or later-model coils- all depending on your personal preferences, what game you are working on, and your own technical abilities. Replacement coils are available on our Electronic Parts page.

Here is a picture of two later-model flipper assemblies installed in a Stern "Meteor" pinball machine, using the original "short" coils:



For example, if you are working on an older game that uses shorter 1-3/4" flipper coils, you can keep and re-use these coils on the new assemblies. The only requirement for doing this is that the new flipper assemblies must have two new screw holes drilled and tapped in the baseplate, so that they will accomodate the shorter coils. This requires some skills in measuring, drilling, and tapping for new screw threads, in order to re-locate the front coil mounting bracket further back on the baseplate so it holds the short coil secure.

The baseplates for each unit seen in the picture above have had new holes drilled and tapped for mounting the front coil bracket further back (due to the shortness of the original style coil). You can see the original screw holes for the longer style coils (used in later games) still in place.

Some later-model games used longer coils (approx 2-inch) which the new flipper assemblies are already set-up for. On some games you can upgrade from the old short flipper coil to the later-model longer coil. There are some variables to consider such as the wiring configuration and voltage used by the game you are working on. As an example, if you are working on an older Williams solid-state game such as Flash, which uses the SFL-20-300/30-800 flipper coils, you can scrap these and install the longer later-model Williams solid-state coils which are SFL-19-400/30-750-DC (as used in Firepower, Black Knight, and later games). The longer Williams coils can also replace shorter coils of other makes/models, including Stern, Bally, and Gottlieb. The only consideration is that the wiring in the game is hooked up to the coil properly- in regard to the orientation of the coil diode(s) and the two windings used in the coil. Some experience with electronics and working on flippers and coils is a requirement for doing this on your own. See the following section on wiring for more details.

Proper Flipper Coil Wiring:

If you want to replace the coils in your game and are using a different type coil or a different brand coil in your game (such as a stronger/weaker coil, an older/newer coil, a Williams coil in a Bally game, or a Bally coil in a Stern game, etc), you can do so as long as you select the correct coil based on the voltage used in your game, and connect the wiring properly to the new coil. Note that in most all cases, the way the wiring is connected to your original coils will not be the same as the way it needs to be connected to a different coil. Some examination of the replacement coil and it's configuration will be required in order to properly hook up the game's wiring to the new coil.

Your game's existing wiring and the wires to the EOS (end of stroke) switch must be connected to the new coil in respect to the orientation of the diode(s) on the coil lugs. If not, the diode(s) will act as a short-circuit and cause a fuse to blow and damage or completely destroy (short out) the diode(s) when power is appled. The cathode, or "banded" side of the diode always connects to the "hot" or "power" wire. The anode, or "non-banded" side of the diode always connects to the low side of the circuit (return or ground side). See diagrams below for more detail.

As long as the wires are connected properly in respect to the diode's orientation, then the coil will work. The actual coil winding wires themselves that make up the "coil" itself may require the game's wires to be connected to the coil lugs in a specific way- sometimes the "hold" and "power" windings in different or replacement aftermarket coils are "swapped" so the wiring on the coil and EOS switch have to be swapped as well. So if you connect the wires properly in relation to the diode orientation, but experience a problem where the flipper is "weak" or the coil heats up quickly, then these can be good indications that the "power" and "hold" windings in the coil are swapped/reversed and some wiring needs to be changed for proper coil performance.

This is not something that everyone will be comfortable doing or even qualified to do, so enlist the help of an experienced service person if you require assistance, or consult the online do-it-yourself pinball repair guides at: www.marvin3m.com/fix.htm. The wiring diagrams in the back of your game manual can also be a significant help in identifying the power wire, "low" (or ground/return) wire, placement of the EOS switch on the coil lugs, and the proper connection of these items in relation to the orientation of the diode on the coil lugs. Again, please be aware that this "original" configuration may not apply when you are installing a different replacment coil- always inspect the coil's actual configuration to determine how it needs to be connected to existing game wiring.

Wire colors, coil types, and the way they all connect, will always vary from year to year, manufacturer to manufacturer, and even game to game, so it is important to understand and identify everything correctly before attempting the work. These are important aspects of connecting a coil to any wiring- there is only one way to get it right, but many ways to get it wrong and end up blowing a fuse or shorting out and destroying the diode(s) on the coil lugs.

Wiring diagrams for common Bally and Williams coils (1977-1985 games):


(Bally coil shown here is AQ-25-500/34-4500 type. Williams coil is SFL-19-400/30-750-DC type.
Flipper Bats:

Flipper bats can often be retained and re-used. This gives an "original" look to your game, even though the parts under the playfield have been upgraded. If you need or want to install new flipper bat/shaft units, you can purchase white or yellow flipper bat/shafts from our General Parts & Supplies page in the "Flipper Parts" section.

Overall Review of Flipper Assembly Upgrade/Replacement Procedure:
The basic process for replacing old flipper units with the later-model units is as follows:

  • Obtain new assemblies (baseplates and mechanical parts).
  • Obtain new coils or retain and re-use your old ones.
  • Obtain new flipper bat/shaft units or retain and re-use your old ones.
  • Remove old flipper bat/shaft units from game.
  • Cut or desolder wires from flipper coils (you may want to label the wires before cutting if you will be re-using your original coils).
  • Remove old flipper assemblies completely from game.
  • Install coils on new flipper assemblies and properly connect wiring between coil and EOS switch (for older games using high-voltage EOS switch). See section above on wiring for more details.
  • Properly orient and install new flipper assemblies in game.
  • Install flipper bat/shaft units, align, and tighten.
  • Adjust EOS switch on each flipper assembly for proper operation.
  • Properly connect wiring to flipper coils on new assemblies. See section above on wiring for more details.
Some additional/spare parts to consider:
This should be enough info to get you started on your way to better flipping. If you need more info, feel free to e-mail us, or for more information on rebuilding and assembling Williams style flippers like these, see the handy online repair guides at: http://www.marvin3m.com/fix.htm

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