Flippers and EOS (End Of Stroke) Switches

Flippers, the most important part of any pinball machine. This article applies to most pinball machines that were manufactured. But a few models/brands did do things differently and are not addressed here.

  The switch i am writing about is the switch located under the plafyeld that will be opened up (means contacts will be separated) when the flipper reaches it’s full up position. It is important that this switch works correctly for a couple of reasons.


If the EOS switch Never closes, which means the contacts never touch, the flipper will be very weak and seem like it has no power. Even contacts that look like they are closed may not be working correctly see my articles on “Understanding Wire Connections” and “Adjusting Switch contacts” for details on this. This condition is not harmful to the machine but in some cases the flipper will be so weak that it will just quiver or not seem to work at all. The eos switch is a high current contact and if they are corroded bad enough replacement of the eos switch is the best repair.

The opposite problem where the EOS switch never opens up but always is closed and passing current can cause a bigger problem. And one you may not immediately realize. The EOS Switch is protecting your coil from excessive current flow. When that switch opens up a coil with a much higher resistance is connected in series with the flipper main coil. This allows you to  hold the flipper button down and keep the flipper in it’s fully extended position without burning up the main flipper coil. The problem would be quickly noticed once your 5 year old nephew presses in the flipper button and won’t let it go for a few minutes. You will quickly smell smoke and possibly a fuse blowing. Don’t ignore this, if this happens to you and you just replace the fuse and go you are missing the real problem. If you blow these fuses often or your coils look burnt up you just may have a EOS switch problem. Again the articles mentioned above should help you solve these issues.