Parts / Vendors

Connectors and Wire

There are a lot of connectors involved in just getting the basics of a pinball machine going here. Since it took a bit of work to track down, here’s the break down.  All part numbers are Digi-Key numbers.  This is quicker for me to use for reordering 😉

An alternative to Digi-Key is Great Plains Electronics ; this guy has a lot of the common pinball parts below, for cheap.  However, when I was ordering his store was closed as this is a side project for him / was overwhelmed with orders.

Molex 0.1″ (2.54mm) spacing

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Used by PinballControllers.com boards for interconnects

  • WM2011-ND – CONN HOUSING 2POS .100 W/RAMP
  • WM2012-ND – CONN HOUSING 3POS .100 W/RAMP
  • WM2019-ND – CONN HOUSING 10POS .100 W/RAMP
  • WM2758-ND – CONN TERM FEMALE 22-30AWG
    • Current Rating: 2.5 Amps
  • WM2400-ND – POLARIZING KEY FOR .100 HOUSINGS
    • this is to make a ‘keyed’ connector with one pin blocked

Molex 0.156″ (3.96mm) spacing

There are IDC connectors found all over pinball machines old and new.  IDC-style (Insertion Displacement Connector) are used in factories where they want to be quick to manufacture harnesses.

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For home use, I’m going with crimped style.  Remains to be seen if this was smart or not.

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  • WM2122-ND – CONN HOUSING 2POS .156 W/RAMP
  • WM2123-ND – CONN HOUSING 3POS .156 W/RAMP
  • WM2129-ND – CONN HOUSING 9POS .156 W/RAMP
  • WM2302-ND – CONN TERM FEMALE 18-24 AWG TIN
    • Current Rating: 7 Amps with 18AWG
  • WM2404-ND – POLARIZING KEY FOR .156 HOUSINGS

MicroFit 3.0

These aren’t part of normal pinball machines, but I decided after talking to the guys on the pinball developers slack channel that this would make a good “entire playfield” type connector.  If I want to remove an entire playfield from the game, I don’t want to have to undo the entire thing.  I figure 2-3 of these 24-pin connectors will be enough; each pin rated for 5 amps continuous duty.  The terminal pins are available from 20-30AWG

  • WM2494-ND – 043025-2400 – CONN RECEPT 24POS 3MM DUAL ROW
  • WM2488-ND – 43020-2400 – CONN PLUG 24POS 3MM DUAL ROW
  • WM1837-ND – 43030-0007 – CONN TERM FEMALE 20-24AWG TIN
  • WM1841-ND – 43031-0007 – CONN TERM MALE 20-24AWG TIN

I may have to end up moving some of the controller boards to the bottom of the playfields for this scheme to work as, since the pins are 5 Amps but, as we see below I have 10 Amp failure cases, I may have to spread power across a few pins.  I would run out of connector space if I had to do that per solenoid

Wire itself

Also pointed out to me by the pinball dev slack channel was where to get a good deal on wiring.  All Spectrum Electronics has 100 foot spools of 22AWG wire in 10 different colors for $6.09 a piece. I now have the full set!

20170501_065450

A lot of the time you see two wire gauges in pinball machines.  There’s the low current wire types, often <=22 AWG for switches and lights, and then there’s the flipper solenoids and other high energy devices,  usually 18 AWG.

There are a lot of current carrying charts out there that indicate the maximum continuous duty amperage based on wire thickness for chassis (short distance) wiring.  Unfortunately, they are all over the place because it really depends on a lot of factors (allowed voltage drop, allowed rise temperature, and jacket material to name a few), and so any chart/table is going by rule of thumb or electrical code which is trying to paint in broad strokes / conservative.

So, anyways.. roughly then a rule of thumb range could be:

  • 18 AWG (1.024mm)= 10-16 Amps
  • 20 AWG (0.812mm)= 7.5-11 Amps
  • 22 AWG (0.644mm)= 5-7 Amps

I have a 10 amp fuse between me and the wall for the net total power.  I have 4 amp fuses between the banks of 8 solenoids and the power.  The power supply rated for 8amps on 48v line.

The beefiest solenoids in the whole thing are the flippers.  Flippers are funny in that they are dual wound.. there are two magnetic coils there.  One powerful one for the stroke of the flipper, and a weaker one for when you hold the button down continuously to catch or other fancy flipper work.   It activates at the “end of stroke” of the flipper.

The primary coil has a resistance of only 4.7 ohms.. if one gets stuck on instead of transitioning to the hold coil, it would be roughly 10 amps @ 48V (Ohm’s Law).  Which makes 18 AWG a good choice to be in the clear for a stuck on, and for some reason the fuse failed, situation.

Link to exhaustive list of solenoids used in pinball machines over the years, with their resistance.  https://www.flippers.com/coil-resistance.html

At any rate, I started this post thinking I was just going to use 22AWG for all wiring. The justification was that if the fuses blow appropriately, then a coil shouldn’t ever exceed the 5-7 Amps for long enough to overheat the wiring.   After working through this a bit more for this post, I think if I were to standardize on just one wire gauge, 20AWG would be better suited, with a little more margin for the high power devices without getting so big for the simple switches and things which have no current.   For me, since I went “all in” on 22 AWG, I’m now ordering a 5 color 25ft pack of 18 AWG vs a full rainbow of the other colors.

Spades / Ring Terminals

Just random stuff from hardware store.  I did realize that these terminal blocks have different spacing between the studs and you can buy spades that don’t fit your terminal blocks.

Crimper

Amazon cheap racheting crimper.  I got this for cheap Dupont style connectors but working well on all of the above. I do have to use the size down on the terminals that 22AWG is the lowest end of the range.

HT-225D Full Cycle Ratchet Crimper

I am slowly getting better at crimping. However, I still usually follow up a crimp with a quick nip of solder.  Someday I will not need this assurance but not yet!

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