Power filter/capacitor board for custom build pinball machine

Thread Starter


Joined May 28, 2019
Hi all, I'm Raymond and I just joined this forum!

I'm in a very long running project (several years) to build a custom pinball machine from the ground up, which includes woodworking, photoshopping, software development, electronics, etc. I'm a software developer and I'm very eager to learn everything that is needed to complete my project.

Currently I'm facing a power issue in my flipper circuit. As soon as one of my flipper fires, my power supply will "shut down" because of the short circuit protection due to the sudden draw. Therefore I need add a power filter board or capacitor board to "buffer" and offload the power supply. I can buy ready-to-use boards for pinball machines online, but I want to build/design it custom and add more functionalities later, like a coin door interface (which cuts high voltage when the coin door is open) and a 48V to 5V step down convertor (to power my Arduinos via the same power supply).

Now I have very basic knowledge of electronic engineering and basic knowledge of components. And with some logical reasoning I can come quite far with designing my own circuit boards, but my main problem is that I have no clue on figuring out which brand or model of certain electronic components to use and why...

What components I think I'll need to create such a board:
  • Connector pins (and cable connectors) for 48V 6.7A power supply
  • Capacitors
  • Thermistor (to prevent the capacitors from triggering the short circuit protection)
  • Multiple power rails
  • High voltage LED(s) (for visually indicating that the capacitors are charged as well as draining them)
  • Connector pins (and cable connectors) for supplying other components (like the flippers) of power and ground via one of the power rails
  • Fuse holders and fuses for protecting the power supply (if needed?)
My questions:
  1. Do I need any more components?
  2. How to decide which connector pins to use for 48V 6.7A? Which can also be easily (dis)connected but will stay connected when in use
  3. How to decide which and how much capacitors to use? A board I saw online had three 8200uF 63V 85C capacitors
  4. How to decide which thermistor to use?
  5. How to decide which LEDs to use?
  6. How to decide which type of fuse holders and which type of fuses to use?
  • Power supply: Mean Well, SP-320-48
  • Capacitor: Cornell Dubilier, SLPX822M063H5P3 (?)
Thanks in advance for any reply!

PS1: The power filter board that I used for inspiration can be found here:

PS2: The pinball machine I'm trying to build is a copy of the Tales Of The Arabian Nights (TOTAN) of Williams:


Joined Feb 20, 2016
You may do better with an simple transformer/rectifier/capacitor supply for the flippers. And a separate supply for the electronics.
Do you have large reverse diodes across the flipper coils? And large reservoir capacitors for your test?
Wiring layout can be important. The high current return needs to go back to the power supply, not using the processor supply return.
Do you have the parts you show, or are you just looking?
That filter looks good, but must be pretty expensive I think.
What is the rating of the flippers? How much current do they draw? And if they have diodes across them, you need to ensure you connect them with the cathode (stripe end) to the +ve supply.
Last edited: