(Topic ID: 275956)

Install caps on EM flippers?

By fixintoplay

3 years ago


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Topic Stats

  • 12 posts
  • 9 Pinsiders participating
  • Latest reply 3 years ago by Tuukka
  • Topic is favorited by 1 Pinsider

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    #1 3 years ago

    I have a Williams SS Pin that has 0.1 uF 500V disc capacitors across the flipper tabs which I’ve just learned help limit arcing and extend life of the contacts. It is considered best practice. Wondering if this approach would also apply to and benefit the EMs I have. They are inexpensive and easy enough to retrofit. Any thoughts appreciated.

    -1
    #2 3 years ago

    You'll get more relevant responses in the SS forum.

    #3 3 years ago

    I did post the question in the SS forum. Awaiting response. But my question is theoretical and relates to EMs, not SS. If this has not been addressed here, perhaps it should be. The caps provide a benefit that was most likely unknown or overlooked in earlier pin years (like keeping flippers from weakening prematurely).

    #4 3 years ago

    What problem are you trying to solve here? It hasn't been addressed here because its not an issue and nobody really does it.

    Your contacts will last years as is so I'm not sure the effort is worth much. Trying to add fixes where there are no problems can often lead to unintended consequences, prob not with this idea, but why introduce something new?

    #5 3 years ago

    I have flippers that are still pretty decent with original switches that I plan to switch out. The games will probably see less play in the next hundred years than they did the first 10 (or less) years when the game was first out.

    I don’t see much benefit in doing so. Maybe put that money towards other components.

    #6 3 years ago

    If your EM games are new enough to have DC powered flippers then yes it would help.

    Remember, basic electronics: a capacitor's purpose is to block DC and pass AC.

    AC powered flippers would not help with this capacitor.

    #7 3 years ago

    This is an answer in search of a problem.

    #8 3 years ago
    Quoted from KenLayton:

    If your EM games are new enough to have DC powered flippers then yes it would help.
    Remember, basic electronics: a capacitor's purpose is to block DC and pass AC.
    AC powered flippers would not help with this capacitor.

    So, does that mean a capacitor cannot function in an arc-supression role in an AC- powered switching circuit? I read a number of articles on the negative effects of arcing on switch contacts before I posted, and I did not see an AC vs DC delineation.

    #9 3 years ago

    You are going to see a lot of arcing inside the cabinet as well.

    If you are concerned about switch wear from arc, don't. You'll be chasing yourself forever. If you have a switch that is severely damaged, clean the contact or replace the switch. Otherwise keep on flipping!

    When EM pinball machines were made they were not designed to last as long as they have. I don't think they were worried about the long term effects of arcing.

    #10 3 years ago

    Mentioned this in the original thread, but:

    As Ken said, this won't really work the same with AC.

    The only EMs with DC flippers are the last few gottliebs, all sorta rare.

    The amount of arcing, and how much the caps help, also depends on voltage, so since most EMs are 25V it's not going to matter as much.

    Ballys might benefit from it on the pops I guess?. I've heard of a few people putting caps on their Bally SS games and saying it did help with the arcing.

    #11 3 years ago

    A little background on why arcing happens at all and AC vs DC: https://pinside.com/pinball/forum/topic/dremmel-for-contacts#post-4235465

    Suppressing arcing in a solid state game is more important because many of the electronics are easily damaged by high voltages and arcing has the potential to expose the electronics to higher voltages than they can handle. Even though the arcing usually occurs at a mechanical switch the impulse can travel through the wiring to sensitive devices on the boards unless properly handled.

    Arcing on an EM game does impose some wear on the switch contacts but the contacts are usually sized appropriately to handle it. Check a pop bumper relay for example. The switch that delivers power to the pop bumper solenoid will have much larger contacts than the switch that delivers power to the 100 point relay. You'll occasionally find a resistor across a switch to reduce the arcing in an EM game but most switches are left unprotected. It probably wasn't considered enough of an issue to worry about. I'm not aware of a large scale EM switch contact wear problem so they were probably right.

    /Mark

    #12 3 years ago

    Just a capacitor, probably not. Sometimes a series capacitor-resistor combination is used as suppressor on AC contact points. You could try 0.1 uF in series with 470 ohm across switch. But as AC coils tend not to generate as large inductive spikes as DC coils, there really is not much need for a suppressor in low voltage AC coils.

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