This one is going to be a little bit controversial if you’re an old-school pinball person, but I’m going to make the case for using off-the-shelf switching power supplies for your Custom Pinball Machine…
Here are the specific ones that I have used in the last four games that I’ve built:
Obviously both made by Lamda, one is 36V nominal for solenoid coils (32V – 40V adjustable) at 4.3A output, and the other is 5V nominal for lighting and control electronics (4.7V – 5.5V adjustable). These are typical closed-frame power supplies used in industrial equipment.
I usually set the higher voltage supply to about 38V, which is plenty for flippers, and can drive the heavier loads like resetting drop-target banks. I also usually boost the lower voltage to 5.5V (or 6V even if you use a different version) to add a little extra punch to the lighting. Most of the 5V components either have their own 5V regulators on-board (and thus may require a slightly higher voltage), or can tolerate a slight boost.
Here are some points to help justify this decision, and convince the die-hard transformer crowd:
- Most games these days only require two different voltages, and thus the cost savings of an all-in-one multi-tap transformer are no longer realized. Older Solid-State games had as many as five different voltages…
- Most people now use LED lighting, at much lower currents. Older games with incandescent lights had huge power draws, and required large supplies. General illumination was the main energy consumer in older games.
- The idea of having lots of continuous current available for driving solenoids is counter-intuitive. Most older machines fused their 43VDC power at 5A max. Having excessive current available only makes it more likely to burn out solenoids (or fuses if you’re lucky). A power-limited supply makes it virtually impossible to burn out a coil.
- Most games will usually only have one- or two solenoids firing at any one time. In my games, 4A at 38V is more than enough to fire four flipper coils simultaneously…
- Modern switching power supplies are smaller, more efficient, and not as noisy as their earlier counterparts. In the old days, designers avoided switchers because of conducted noise issues at the high power required for older games.
- Large capacitors are easier to get these days, and can better compensate for surges that previously had to be mitigated by going to higher power ratings.
Buying an off-the-shelf industrial power supply is not only convenient, it can also be cheaper than some of the custom- or purpose-built “pinball” power supplies available, which are usually overkill for what is actually needed.