The Modern Firepower Pinball Project - Playfield Test [VIDEO]

Over the past few years of doing research and development, many times I have had doubts about my ability to build a pinball machine from scratch.

Occasionally a milestone is achieved, like the first time a solenoid is activated from a home-built power supply, or the first time a program you wrote recognized a switch input and energized a solenoid.

Each of these achievements gives you new confidence, but the doubts still linger in the shadows of your mind.  Sure, the individual tests were great, but what happens when you scale up to a full machine?

After a few months of careful assembly and wiring, I was finally able to put all of my doubts to rest.

In mid March I was able to play my first pinball game on my 'Modern Firepower' playfield, and the early results were fantastic.  I put together a multi-angle video to show off my hard work, I hope you like it.

Make the jump for the video...

The Modern Firepower Pinball Project - Power Supplies

WARNING:  THE CIRCUITRY DESCRIBED IN THIS POST USES ELECTRICITY AT LEVELS DEADLY TO HUMANS.  SEEK PROFESSIONAL EXPERTISE IF YOU ARE NOT SURE HOW TO SAFELY USE THE PRESENTED INFORMATION.

One of my very first achievements on my long pinball quest was a home-built solenoid power supply.  Though it was many years ago, I still remember clearly the first time Troy and I activated an old, used and abused solenoid with my home-built power supply.  At that moment I felt like a magician harnessing an invisible, mystical power.

The bottom half of this Williams 'High Power Solenoid Circuit' actually describes most of the power supply design.  J102 is the signal coming from the Transformer, which runs through a Bridge Rectifier (BR3), and a small Capacitor (100uf) and Resistor (10KOhm) provide a small amount of line conditioning.  Not shown here is the circuitry (Switch, Fuse, Line Conditioner and Varistor) that are in the circuit between the AC power source and the Transformer.

But as with most things pinball, for the DIY enthusiast there is a great void of information for what should be a relatively simple topic.  I had spent months researching and building the power supply from scratch, and had no idea if it would really work with pinball solenoids.  It was at that moment, hearing the BAM BAM BAM of the happily activating solenoid, that I first felt capable of overcoming the challenges of building my own pinball machine.

I wish I had all the answers, but to be honest there's still several aspects of pinball power I haven't had the opportunity, or the need, to solve.  But many of the answers I will be providing here I have never seen published anywhere else.  And trust me, I looked.

Power supplies in and of themselves are not complicated beasts.  Any number of books and resources will teach you how to build any of the many types of various power supplies.  If you are interested in building a power supply, I highly recommend you read up before tackling your own project.  In case you're curious, I read 'Building Power Supplies' 2nd Edition by David Lines, which I had picked up years ago at RadioShack for other projects. 

I do not provide enough info here to guide you through the process; rather my goal here is to help you choose the correctly sized power supplies that are needed for a modern, DIY pinball build like my Modern Firepower Pinball Project.

Power supplies are needed for several items in a modern pinball build, primary among those are the solenoids and the bulbs.  In my modernized pinball build, I'm also using a power supply for an industrial USB hub (which in turn powers four connected USB peripherals), and for the ball trough opto-switches.  If you're using any special anima-tronics with motors, you might also need a different voltage power supply just for them.  Every build can have unique requirements, so your choice of components and features will ultimately drive your power supply requirements.

Since I'm using an 32" LCD TV for the backbox (which also powers the speakers), I didn't have to worry about backbox lighting and audio amplifiers.  Obviously the TV came with it's own power supply (built in).  The only other device in the pinball machine is the small PC running Windows, which came with its own power supply.

Since the only real challenging power supply is the solenoid power supply, I'll discuss the other power supplies first, and save the best (worst?) for last.

Read on for more info...

The Modern Firepower Pinball Project - Lighting Demo

The lights are fully wired up and tested, and I thought it was time to show them off.

Switches, Lamps and Solenoids are all wired up.  The playfield is almost ready to go into the cabinet.

In the picture above, not only are the lights wired up, but so are the solenoids.  The playfield is almost complete, ready for installation into the cabinet.  I've simply fallen behind on updating the blog.

The only wiring left to complete is the switch and solenoid wiring for the very top eject hole.  I won't be able to install the eject hole assembly and switch until the playfield is removed from the rotisserie, so for the moment wiring is complete.

Click on through to see the pictures and video...

The Modern FIrepower Pinball Project - Shocking Discoveries

Though overall progress has been slower these past few weeks, wiring is coming along nicely.  48 lamps have been wired up, and I have about 30 more lamps to wire.

Lighting wiring:  Red wire is shared 5v power, green wires are ground control lines that run back to the LED-Wiz.

In the pictures, the red wires are providing shared 5v power to the bulbs, and I used all green wires for the individual grounds that run back to the LED-Wiz.  I have no idea which lamp connects to which port, and I don't need to know since my software will map the lights.

Yes, pinball bulbs are typically powered by 6.3 volts, but I already had a 5 volt 2 amp power source handy, and I found that the brightness was just fine using only 5 volts.  I will cover the power supplies in a later post.

For now, read on to discover the shocking oversight I made in my electrical design...

The Modern Firepower Pinball Project - The New Solenoid Power Driver

In the previous update on the Solenoid Power Driver I explained that I had submitted the new PCB design to manufacturing, and also ordered new transistors.

The PCB's came in and they look marvelous!  These prototype PCB's were proudly manufactured in the USA, though I'm not sure where ExpressPCB conducts their full-scale production runs.  This was my first time using ExpressPCB, and I am very pleased with the results.

All the various components fit perfectly onto the ExpressPCB manufactured prototype PCB.

The new design is revision 3.0 of my Pinball Solenoid Power Driver, and is optimal for use with the LED-Wiz as the controller.  Compared to my original design, the new circuit board is not only smaller, it upgrades all outputs to High Power circuitry, and adds fuses for each output as well as the main power source.

My original prototype (brown) had 4 High Power and 12 Low Power circuits, and no fuses.  My new design is much smaller, yet it provides 16 High Power outputs. Every output is fused, along with a separate fuse for the power supply.

The new transistor came in as well, and it... was promptly fried.  Faster than corn in hot oil, these transistors popped as soon as a solenoid load was introduced.  Lowering the voltage to 25V from the normal 50V, these transistors worked just fine, but the solenoids fired weakly.

So now I had a new challenge, to find an even better transistor, but in the same package with the same pinout, and electrically compatible with my freshly milled PCB boards.  The task seemed impossible.

I'm happy to announce that I was successful in my search.  Instead of trying yet another BJT transistor, I went with a Power MOSFET transistor.

Power MOSFETs are different from BJT transistors in that MOSFET's use a small voltage to control a large current, whereas BJT transistors use a small current to control a large current.  Lucky for me, they are available in the same TO-220 package, and the pinout is fully compatible with my existing circuit design.

Testing the new Power MOSFET transistor.  Worked perfectly each and every time.

In preliminary testing the Power MOSFET transistor has performed perfectly.  From a technical standpoint, this transistor even appears to be superior to the MOSFET that Stern Pinball uses, or at least used at one time.  I haven't bothered to research if Stern has chosen different MOSFETs for their more recent games.  Not only is my chosen MOSFET capable of handling more power than Stern's counterpart, it also has quicker response times - roughly twice as fast.

Now the the PCB is assembled, it's time to do some testing.

I've soldered up the first PCB, and it will soon undergo performance and endurance testing in the Modern Firepower pinball machine. 

The new Pinball Solenoid Power Driver v3.0 is small enough to fit snugly on the Modern Firepower playfield.

Wiring for lighting, and now solenoids, continues.  More updates soon...

The Modern Firepower Pinball Project - Switch Wiring

During the week I completed most of the switch wiring.  It was rewarding to hook the switches up to the PC and monitor the inputs, and every switch tested perfectly!

Switch wiring is 80% complete and tested!

Click on through to check out the details...

The Modern Firepower Pinball Project - Prep for Wiring

In prep for wiring the playfield, I'm test fitting all of the various circuit boards and components onto the underside of the playfield.  I have to find a place for three LED-Wiz output driver boards, one U-HID switch input board, one Pinball Solenoid Power Driver board (of my own design), and a USB hub to tie them all together.

From the original design concept, I intended to install the circuit boards directly to the playfield.

It is not a requirement that I install any of these components to the playfield.  Alternatively I could have installed the circuit boards in the backbox, like a normal pinball machine.  To install the boards in the backbox would require me to fashion up several wiring harness connectors, as there would be around 150 wires connecting to the playfield.

But since my circuit boards are so small and fit on the playfield, I will only have 3 wires connecting to the playfield:  The 50v power supply, the 5v/12v power supply, and a single USB cable.

Now that's the definition of Modern.

The Modern Firepower Pinball Project - Cabinet Assembled

I finished painting the cabinet, and with Troy's help we got it mostly assembled.  For now I'm going to leave off any artwork, I find the all black cabinet to be classy and different.  The paint is a semi-gloss, so those are soft reflections you see on the side of the cabinet.

The cabinet looks classy its black and chrome motif.

I haven't painted the backbox.  The front wood panel that covers the monitor and holds the speakers needs to be designed, routed and installed before I paint it.  The speakers that are dangling from the monitor are the original speakers that came on the 32" TV.  Since they are not very good, I will replace them with either 6 1/2" or 6" x 9" car audio speakers, which I haven't yet picked out.

The Modern Firepower Pinball Project - Lights Installed

All of the lights have been installed on the playfield.  At this time, the underside hardware installation is 99% complete.  There is a mechanical beauty to an un-wired playfield.  If only it could stay looking this nice.

Take note of the open areas that remain on the playfield.  My selection of modern components have freed up additional room around the slingshots and eject holes.  This will allow me to do something pretty special - I will be mounting the circuit boards to the playfield itself.

I installed the lights in a tidy fashion to minimize wasting of open space.

More pics after the jump...

The Modern Firepower Pinball Project - Solenoid Power Driver Design

WARNING:  THE CIRCUITRY DESCRIBED IN THIS POST USES ELECTRICITY AT LEVELS DEADLY TO HUMANS.  SEEK PROFESSIONAL EXPERTISE IF YOU ARE NOT SURE HOW TO SAFELY USE THE PRESENTED INFORMATION.

During the course of The Modern Firepower Pinball Project, I've had to don many different caps.  At various times I've been a researcher, analyst, designer, carpenter, painter, mechanical engineer, programmer,  electrical engineer, project manager, financier and accountant.  Now that I think about it, since I'm writing this blog I'm also the writer, photographer, and publicist.  No wonder it has taken me over four years to get this far.

While all of the various tasks interest me (why else would I be doing this project), I understand that many pinball enthusiast, even diy hobbyist, just want to get to the good parts with videos of pinballs bouncing around.  To those readers, fair warning, this is not that post!  As if the title didn't already give that away.

This post is about circuit design and theory, and for most people I would expect this is an extremely boring topic.  Even worse, I plan to share some technical details that many won't understand, including me.  I have no formal education in electrical engineering, and I'm self taught outside of one class in college.  As I share this information, I'll be presenting it in mostly layman terms, not EE terms, as this is how my brain works - I suppose I have a layman's brain.  If you want to understand more about transistor design, usage and terminology, there's plenty of other resources on the web that cover those topics.

If you're a brave soul, you might find this post informative even if you don't have a real interest in electronic design.  I found many forum posts online where people were trying to figure out how to get an LED-Wiz to control pinball solenoids.  Well, this is how.

Now, to the topic at hand...

Rottendog Amusements makes modern replacement Driver Boards like this Williams WPC89/WPC-S replacement.    While it is better than the originals, this board is still rather large, though it does handle more than just solenoids.

The Modern Firepower Pinball Project - The Electronics

I have already provided many posts detailing the cabinet and playfield progress (with many more to come), and now it is time to talk about something different, the electronics of the pinball machine.

Anyone who has seen the inner workings of pinball machines is familiar with the large, complicated circuit boards hidden inside.  These electronic boards are custom designed for pinball machines - often specific to a single game design.  Hundreds of color coded wires run from these boards to other boards, the playfield, and other areas of the cabinet.  It's an electronic nightmare.

Found on the web, this ActionPinball.com image shows many of the common circuit boards hiding in a pinball backbox.

When I first started the project, I briefly considered using these original pinball circuit boards - after all, if it already works why re-invent the wheel.

But using 30 year old circuit boards, possibly designed for an incompatible game and running hard coded firmware, just didn't align with any of my goals.  Nothing modern about that approach.  Rather, I wanted to use off the shelf, generic circuitry where possible.  Besides, these pinball specific circuit boards are expensive.

I also looked at programmable microcontrollers like Arduino and Parallax.  +Ben Heck had chosen the programmable microcontroller path for his pinball machines, and I knew it was cost effective and functional, but I found this approach was too limited for some of my goals. Sure, these devices were powerful, and could easily control lights, solenoids, switches and audio, but I wanted video too.

More importantly, I wanted a solution that could adapt to any pinball machine without writing new code.

From this point forward I will begin to show you what makes the Modern Firepower Pinball Machine so special, and unique in all the world of pinball.

The Modern Firepower Pinball Project - Ablaze 9-LED #89 Flasher Lamps

In the previous update I showed that the Ablaze 9-LED flasher lamps, which run on 12 volts, would not light up at all on 5 volts.  I dug out my 12 volt power source and tried again, this time to spectacular results.

With 12 volts now running through its veins, the 9-LED #89 bulb shone brightly.  On the left is the 4-LED #44/#47 bulb.

The Modern FIrepower Pinball Project - Lighting Issues

The curse of incorrect parts has reared its ugly head again.

I can't blame the vendors, as I've always been delivered exactly what I ordered.  I don't really want to accept blame myself either, as you can't deduce everything from photos of individual parts.  I guess once again I'll blame the parts ecosystem that simply isn't designed to support the diy pinball hobbyist.  I've never seen any write-ups detailing the correct style bulbs to use when making your own pinball from scratch.  I guess it is up to me, then.

So here's what I chose for lighting, why it was wrong, and what I chose to replace it.

The Modern Firepower Pinball Project - Painting the Cabinet

Since I had some downtime waiting for replacement parts to come in (more on that later) I decided to go ahead an paint the cabinet.

First I finished cutting the ventilation holes and the hole for the ball shooter.  I post later about how I lined up the ball shooter.

Then I sanded, puttied, sanded, puttied, and sanded some more.

Finally, I primed the cabinet.  Primer reveals all kinds of imperfections, so I then spent another day applying wood filler and sanding everything down.

First of many many coats of primer.  I'm using Rust-Oleum Painter's Touch white spray primer.

The Modern Firepower Pinball Project - Targets & Switches

The various targets, stand up leaf switches and rollover switches were all very easy to install.

The targets took the most work, since they are visible and I wanted their alignment visually correct.

The leaf switches I installed by tapping the rubber rings (simulating a pinball hitting them) while positioning each switch - when correctly positioned I could hear the small metallic tap tap tap of the switch contacts.  I then marked and drilled the holes.  The rollover switches I simply visually aligned.

 

Read on to see more pictures...

The Modern Firepower Pinball Project - Playfield Machinery

After installing the various posts on the playfield, I turned my attention to the playfield machinery.

I had already decided that there was a correct order for installing all parts on the playfield.  Posts first, simply because they are small and on the top.  Then machinery, because there's normally only one correct way to install these large metal assemblies.  Next come targets and stand up switches, as they too can only be installed one way.  Then come the rollover switches, which have a little more leeway in installation location.  Last come the lights, as they have the most flexibility in installation location - so long as they are under the correct insert or hole, you can mount them however you like.

I installed the pop bumpers first.  These are standard Williams style pop bumpers.

The Modern Firepower Pinball Project - Playfield Posts Installed

It should be quite obvious by now that I did not achieve my goal of having a playable pinball machine by New Year's.  The factors were twofold:  missing or incorrect parts, but more importantly a massive underestimation of the work it takes to assemble a playfield.

I foolishly expected assembly to be somewhat plug and play, and thought I would crank it out in a few hours.  Reality is that you have to carefully check every part, align every hole, drill every hole (making sure not to drill all the way through the board!), and then screw in very carefully each part.

The posts alone were taking about 10-20 minutes each, and there's a lot of posts.  Part of the challenge is making sure the right post, or post screw/bolt, is being used at each location.  Make the wrong choice and you might drill the hole incorrectly.  There's really only one shot to get everything right, so I took my time.

I also learned the hard way to make sure to drill the pilot holes to the correct size.  I was slightly small on many of my holes, and actually snapped a screw post off in the playfield!  The post broke off flush with the playfield, and my attempts to simply remove or drill out the post, without damanging the playfield, were unsuccessful.  I finally drilled small pilot holes all around the sides of the broken post until I could free it.  To fix the playfield, I drilled a larger hole to permit the use of a bolt post and T-Nut.  Then end result is even better than stock, so I consider myself lucky.  I really wish all post holes used T-nuts and bolts instead of wood screws - they install faster and seem more robust.

The Modern Firepower Pinball Project - Playfield Support Rails

Progress on the cabinet is coming along nicely.  Time to make sure everything fits correctly and install the playfield support rails inside the cabinet.

Test fit of all cabinet hardware.Time to install the playfield support rails.

The Modern Firepower Pinball Project - Coin Door Luck

While I spent a lot of time and effort measuring, test fitting, and reverse engineering how all the various cabinet components had to be installed, on a few occasions lady luck was on my side.

I got really lucky when I installed the coin door.  It never occured to me that the coin door and the lockdown bar retention bracket bolt together.  When I cut the hole for the coin door, I simply centered it left to right, and arbitrarily picked a height that looked appropriate.  Sure, I stared at dozens of pictures before deciding where to locate the coin door, but the pictures below show luck was on my side.

The coin door is installed with four bolts, centered on the bottom, sides and top.  The top hole goes through the bracket.

The vertical alignment was perfect, and I was able to install the bolt and nut without issue.

 Now that you know, you don't have to be lucky like me.  Plan ahead.

The Modern Firepower Pinball Project - Stern Backbox Hinges

The parts for the Stern Backbox Hinges came in from Marco Specialties.  I took plenty of pictures, so I'll let the pics do most of the talking this time.  Note, I did not have the washer in the photos, nor did I install the washer.  Everything seems to work without the washer, and as rarely as I will every pivot the backbox, I probably will never use a washer.  If I change my mind, I can always install it later.

The Stern Backbox Hinge Bolt assembly includes a Hex Spacer Nut, a Carriage Bolt, a plastic spacer, and a washer (no pic).

Click through for all the details...