(Topic ID: 222617)

why is there a resister and cap on the popbumper''s spoon switch?

By wdennie

5 years ago



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Williams_Pop_Bumper_Switches (resized).jpg
#1 5 years ago

Having a problem getting the right popbumper too work, on my space shuttle.
I thought it was a switch problem, coil would fire once and then nothing, but started me wondering why do these switches have a resister and cap on them when the rest of the switch's have a cap and diode?

#2 5 years ago

Could be wrong about this but I believe the cap is/was used to "speed up" reaction time of the pop firing - someone jump in here if that's not the case .

#3 5 years ago

yes. the cap draws out the signal longer so the CPU can see even fast hits as full hits.

#4 5 years ago

so why the resister, and not a diode?

#5 5 years ago

seems like the resister would drain the cap.

#6 5 years ago

What value is the resistor? The resistor would create a voltage drop.
You don't want to lose voltage here.
Maybe someone in the past replaced the switch diode with a resistor.
Have you tried replacing the resistor with a diode as per the others?
A schematic should confirm what is what.

#7 5 years ago
Quoted from Rikoshay:

What value is the resistor? The resistor would create a voltage drop.
You don't want to lose voltage here.
Maybe someone in the past replaced the switch diode with a resistor.
Have you tried replacing the resistor with a diode as per the others?
A schematic should confirm what is what.

Voltage drop doesn't matter at all. Resistor is per design, it just has to keep it above 3ish volts

#8 5 years ago

I'll need to see a high quality scan of the schematic from e.g. Staples ($2) or Kinkos ($6).

#9 5 years ago

Here is a part of the schematic used for pop bumpers in Williams games.
This part came specific from Contact, but it's the same for all games of thise era.
The resistor is 100 ohm and the cap is 22uF/10V (but may be higher voltage).

Williams_Pop_Bumper_Switches (resized).jpgWilliams_Pop_Bumper_Switches (resized).jpg
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