What's the purpose of a modern Stern EOS switch?

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#1 7 years ago

OP

MSF

Nokoro

Pinside+ Frequent

10y 137K 5,484 18

I ask because I recently noticed that the little hammer that opens the switch fell off of one of the flippers on my Star Trek Pro. I don't know how long I had been playing without opening the switch before I saw the broken hammer. But, I didn't notice a difference in game play and didn't melt the coil. I then replaced the hammer. Subsequently, I noticed that the leaf on the EOS broke off on the same flipper (after I replaced the hammer). So, effectively, the switch was in the open position during countless games without me noticing.

I understand the purpose for the switch on older games, but does it have a different purpose on newer Sterns? Why did everything appear normal when I was playing with, in one instance, a closed switch all the time, and, in the other instance, an open switch all the time?

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#2 7 years ago

LEV

CrazyLevi

Crazy Levi's Pinball

New York, NY

10y 148K 33,497

They help improve feel and response. But the game should function without them.

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1

#3 7 years ago

QRK

Deez

Pinside+ Frequent

12y 134K 6,776 13

It prevents flipper bounce when the ball hits the flipper really hard.

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#4 7 years ago

LFS

pinballaddicted

Pinside member

9y 123K 4,410 81

OP
Quoted from Nokoro:
I ask because I recently noticed that the little hammer that opens the switch fell off of one of the flippers on my Star Trek Pro. I don't know how long I had been playing without opening the switch before I saw the broken hammer. But, I didn't notice a difference in game play and didn't melt the coil. I then replaced the hammer. Subsequently, I noticed that the leaf on the EOS broke off on the same flipper (after I replaced the hammer). So, effectively, the switch was in the open position during countless games without me noticing.
I understand the purpose for the switch on older games, but does it have a different purpose on newer Sterns? Why did everything appear normal when I was playing with, in one instance, a closed switch all the time, and, in the other instance, an open switch all the time?

Sam system will blow a transistor on the drive board if you keep holding the switch on. You have been lucky. EOS switch does the same thing as older machines without the wires. The EOS switch changes the voltage to the coil on the driver board. If you start blowing flipper fuses, it will be the transistor on the board.

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#5 7 years ago

OP

MSF

Nokoro

Pinside+ Frequent

10y 137K 5,484 18

Quoted from CrazyLevi:
They help improve feel and response.

How so? Can you elaborate?

Quoted from pinballaddicted:
Sam system will blow a transistor on the drive board if you keep holding the switch on. You have been lucky. EOS switch does the same thing as older machines without the wires. The EOS switch changes the voltage to the coil on the driver board. If you start blowing flipper fuses, it will be the transistor on the board.

I feel lucky as there is no way I would have noticed a problem if I hadn't had to go into my coin box for something and found a strange piece sitting in there -- the first time, the hammer; the second time, a leaf. Still, if it controls voltage, wouldn't the flipper have been really weak with the leaf missing (i.e., switch always open)?

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3

#6 7 years ago

???

Homepin

Inactive member

Unknown

13y 77,400 2,125 1

The EOS switch in modern machines is really only there in case a super fast ball slams into the flipper while it is being held in the up position.

1. press flipper button and main pull coil activates, pulling the plunger swiftly to the upwards position.
2. the MCU starts a timer counting while at the same time the MCU "looks" for a closure of the EOS switch.
3. one of two things now happens here:

A. the MCU sees that the EOS switch has closed - or
B. the timer times out and the MCU "assumes" the plunger has now made it to "flipper up" position

4. the MCU turns ON the hold coil and then turns OFF the pull coil holding the plunger safely in the up position.

The problem now is if a fast ball slams into the flipper the MCU has no way to tell if this event has happened so the flipper will very likely flop to the down position as the hold coil won't have the power to resist EVEN IF you are holding the flipper button ON.

If the EOS switch is intact and working correctly, the MCU would "see" the EOS switch go open and say to itself: "wait a second - the flipper is held in the up position - that's not right" and so the MCU will pulse the power coil again to make sure the flipper remains in the up position.

Post last edited 7 years ago: “correct explanation of the EOS ”

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#7 6 years ago

JDM

martymart

Pinside member

8y 36,550 355 8

Quoted from Homepin:
The EOS switch in modern machines is really only there in case a super fast ball slams into the flipper while it is being held in the up position.
1. press flipper button and main pull coil activates, pulling the plunger swiftly to the upwards position.
2. the MCU starts a timer counting while at the same time the MCU "looks" for a closure of the EOS switch.
3. one of two things now happens here:
A. the MCU sees that the EOS switch has closed - or
B. the timer times out and the MCU "assumes" the plunger has now made it to "flipper up" position
4. the MCU turns ON the hold coil and then turns OFF the pull coil holding the plunger safely in the up position.
The problem now is if a fast ball slams into the flipper the MCU has no way to tell if this event has happened so the flipper will very likely flop to the down position as the hold coil won't have the power to resist EVEN IF you are holding the flipper button ON.
If the EOS switch is intact and working correctly, the MCU would "see" the EOS switch go open and say to itself: "wait a second - the flipper is held in the up position - that's not right" and so the MCU will pulse the power coil again to make sure the flipper remains in the up position.

I know this is an old thread so sorry if this has been raised elsewhere but I was wondering if this would be the same for a Transformers LE as I have just noticed that the EOS on my right flipper is broken. I was wondering if I continue to use the machine without replacing it will it damage the machine or just potentially impact game play and performance.

By Nokoro

7 years ago

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