I've had a few requests to make a new topic post on my DIY flipper coil fans... so here it is.

I am not trying to take any business away from modders who offer quality products. If you prefer easy to install solutions with all the parts you need, then the coil fan kits available on Pinside will work great for you.

If like me, you wanted to add coil fans to several games, a DIY approach was required to keep costs lower. I’m a tinkerer by nature anyway…

I have noticed the effects of flipper fade on some of my Stern machines because I often play sessions of multiple hours consecutively on the same machine. My single longest game of pinball to date was 90 minutes on AIQ and fans help considerably on that game! Once I saw and felt the effects of fan cooling the flipper coils (I’m in the Chiller system manufacturing business, so keeping the coils cooled to help maximize performance always made sense to me) I wanted to do it to all of my Stern machines as one of my first mods when I get them, so I don’t have to worry about flipper fade.

My DIY design is pretty simple and you don't need a 3D printer. For Stern Spike 2 machines - I use 40mm 12VDC fans with a rubber bumper mounted to it to allow space for airflow, loosely tie wrapped directly to each coil. Wire to 12 VDC at CN6 on the backbox power supply. I use a 1 amp fuse and also a diode for protection on the power line that feeds all of the fans.

I’ll soon be adding posts to show what parts I use. It becomes more cost effective, basically the more pinball machines you need to add fans to since some of the items you need to buy have some minimum quantities.

If you have questions, your own success stories or your own way of cooling flipper coils – this is the place to discuss it. I’m starting with Stern Spike 2 machines, but all pinball machines are open to discussion.

IMG_2527 (resized).JPG

IMG_2533 (resized).JPG

IMG_2545 (resized).JPG

I've thought about removing the paper myself. Even though the wire is insulated, I guess it could get nicked and allow a possible short if it touched something conductive. I assume this is why they have the paper on there in the first place.

Here’s how the cooling fan circuit looks on a schematic.

Additional fans can be added in parallel just like the two fans shown. Make sure the total current draw is under 1 amp. Most fans in this class are 0.08 ~ 0.12 amps, so 2 ~ 4 fans shouldn’t be an issue.

There’s a few different places you can power the fans from, I just prefer direct from the power supply 12VDC. I use a 1 amp fuse and also a diode for protection. Fuse prevents overcurrent damage and diode prevents any reverse current flow from the fans to the power supply. Both are cheap insurance and recommended.

awesome1 Flipper Coil Fan wiring schematic stern spike2.jpg

Updated wiring schematic showing diode in parallel around fans instead of in series.

https://pinside.com/pinball/forum/topic/diy-pinball-flipper-coil-fans/page/2#post-7389130

I use a 1 amp automotive fuse, cheap and easy to use and connect with 0.250” quick disconnects. I use 18 awg wire. I also use the male & female quick disconnect to join the fans together to the main power and ground wires.

I had a bunch of the 1N4004 diodes from other projects. I solder them directly inline with the wire and then shrink tube over it.

IDC style 3 position connector to connect to CN6 on the power supply board in backbox.

IMG_2539 (resized).JPG

IMG_2541 (resized).JPG

IMG_2542 (resized).JPG

Updated picture of diode in parallel with fans instead of in series.

https://pinside.com/pinball/forum/topic/diy-pinball-flipper-coil-fans/page/2#post-7389126

Here's a pic of essentially all of the parts you will need. 18 awg wire and some tie wraps are not shown. You will also need a crimper for the quick disconnects and soldering iron for the diode.

IMG_2520 (resized).JPG

The same approach can be used on magnets as well! Here’s what I did on Godzilla:

IMG_2525 (resized).JPG

IMG_2526 (resized).JPG

Fans:

These are cheap for a set of 4 in this 40mm form factor which is just about the same length as the coil. I use the 12VDC style and try to stay in the 0.08 ~ 0.12 amp current draw per fan, while looking for the highest CFM rating. These fans won’t move a ton of air, but you can feel it with your hand and it is plenty to cool the coils. Personally, I don’t use the add-on grills. If you touch the spinning fan with your finger, I’ve never been hurt, but feel free to use them if you like.

https://www.amazon.com/dp/B07S9W1JGB

IMG_2521 (resized).JPG

IMG_2522 (resized).JPG

To follow up... here's completed installation (2 flippers) on a Deadpool.

IMG_2055 (resized).JPG

IMG_2053 (resized).JPG

Completed installation on Godzilla (3 flippers and 1 magnet)

IMG_2551 (resized).JPG

IMG_2549 (resized).JPG

IMG_2545 (resized).JPG

Yes, everything is insulated and Stern is using 48VDC to power the coils, so I don't think it will kill you, but you should be careful around all electrical circuits. The wires that wrap the coils themselves are also insulated, but the voltage is exposed at the terminals.

I have several thousand plays across multiple machines with my DIY flipper coil fans mod and have not had a single issue.

I had heard on early code on Godzilla that there were issues with the magnet getting too hot. I personally never noticed any issues (I think .91 was latest on delivery), but I installed my DIY fans pretty soon after getting my game, so not a lot of games played at that point.

More air could potentially help cool more. There becomes diminishing returns, because you can only cool the coil to a certain temperature differential (Delta T) based on the surrounding air temperature and the heat generated by the coil. I haven't had the opportunity to try higher or lower CFM fans and measure differences. The flippers will never perform better than when you first power the game on... they may remain at that power with cooling fans, but won't get better since you will never cool them below ambient temperature.

In the 40 x 10mm fans I am using, I did search for higher CFM and the ones I got are ~5.5 CFM which is a decent flow for this small fan, but we are also limited by the 12VDC supply I am using.

These little fans definitely help reduce flipper fade and I've played several 2-3 hour or longer straight sessions on many of my games and can open the coin door and grab the flipper coil and it will only be warm to the touch.

Either will work fine. Just based on your preference. CN6 stays powered even when you open the coin door.

CN6 and CN11 can only support 2 amps each max (12 VDC), so as long as you stay well below that and don't have other mods that add up to go beyond those current draw numbers, you should be fine.

If wired properly with fuse and diode, there shouldn't be any issues using a Stern 12V connection as the fans have very low current draw and you have overcurrent and reverse current protection. I have thousands of plays on my games with DIY cooling fans.

Ultimately you should do whatever you are comfortable with. Using a separate power supply is perfectly fine.

This will definitely work - just not as 'elegant' looking.

It's the cab resting on the floor or table that's a little weird...