Thursday, June 29, 2017

"The Black Knight Rises" - Week 5 Progress

Though The Black Knight Rises missed the show, the work must go on...

Days 29 & 30 - Saturday & Sunday at the 2017 SFGE:
For me, one of the best things about attending the Southern-Fried Gaming Expo is hands-on time with hundreds of machines, including some custom machines.  Sure, I was having fun playing, but this was also work, research to be specific.

As I would play each game, I would make note of any unique features, not just from a playfield design standpoint, but more importantly from a software capabilities standpoint.

For example, I got to play American Pinball's freshly assembled Houdini.  At one point during gameplay, I triggered a mirrored and reversed flipper mode, in which the right button controlled the left flipper, and vice-versa, plus the flipper bats stayed in the upright position, and you had to press the buttons to lower them, releasing to hit the ball.

With a few lines of code, I could certainly add such a routine to the Chameleon Pinball Engine.

It was also a treat to see under the hood of Scott Danesi's most excellent Total Nuclear Annihilation custom pinball machine.  I learned some simple things, like how a drop target can be both raised and lowered by adding a second solenoid to "hit" the target and make it drop, and that there is a stock Williams flapper style one-way ball gate that includes a solenoid to raise the gate, opening a passageway to both directions of travel.  Scott also has developed his own Computer Startup and Shutdown Controller, allowing the standard power switch on the bottom of a cabinet to directly, and safely, power cycle a PC.

I came home with a mind overflowing with ideas, and it will take a while to work through them.

Day 31 - Monday:
I finally rested.  Well, and wrote in this blog.

Day 32 - Tuesday:
While my CNC router has been nothing but problems, my Original Prusa i3 Mk2 3D printer has been beyond amazing.  It finally occurred to me that perhaps I could simply print the speaker/DMD mounting panel, instead of routing it from MDF.

The panels dimensions, at 6" high by 26" wide, extend far beyond the build plate of the Mk2, at 9.8" x 8.3".  I would have to divide the print into 3 smaller sections and assemble later.  Since I already had my 2D CAD model, it was quick and easy to recreate it in 3D on the TinkerCAD website.

Within an hour the 3D printer was churning away the first segment.

3D printing the left speaker mount.  With a 20% infill, the entire assembly should weigh less than a pound.

While the printer was doing its job, I pulled out the Chameleon Power Drivers to do some more testing.  I had the 5 additional boards that I had baked the previous week that were ready to be tested - perhaps one of these would work.  In the back of my mind, a familiar itch told me I was still missing something obvious.

The five power drivers weren't completely assembled.  Solder paste had been applied, the surface mount components positioned on the paste, and the boards baked.  But the fuse holder, power connections, and big daddy MOSFETs were all through hole components that needed to be hand soldered.  Thinking this was a perfect opportunity to isolate components for testing, I soldered on the fuse holders and power connections, but left the MOSFETs off for now.

On the test bench I hooked up the 38v solenoid power supply, and the 5v signaling power supply.  With my multi-meter, I probed the voltage at the MOSFET Gate connection.  As I manually triggered the channel, I watch the voltage drop from 38v, indicating that the first and second stage transistors were working perfectly as designed.  The problem, it seemed, must be with the MOSFET.

I inserted a MOSFET into the power driver and continued to test.  No matter what I did, it continued to remain in the "On" state.  Maybe I had it in backwards?  Rotating the MOSFET around, it now steadfastly remained in the "Off" state.   I ignored the itch telling me I had seen this before, and thought to myself that the MOSFETs were bad.

I tested several more, and each behaved the same way.  How in the world had I received a bad batch?

I gave up for the day, pushing the familiar thoughts away.

Day 33 - Wednesday:
The first 3D printed speaker mount took nearly 11 hours to print.  I woke up to find this waiting for me:

The left side speaker mount finished printing successfully.
I immediately did a little cleanup and placed the part in the backbox to check alignment and sizing.  Satisfied, I started printing the mirror image for the right side.

Checking alignment, the speaker mount fit nearly perfectly - good enough to continue without tweaks.

Next I turned my attention back to the Chameleon Power Driver.  I visually compared a working MOSFET to a miscreant.  The part ID matched, but there were lots of other little numbers and letters printed on the package, what do those mean?  Examining the data sheet, these indicated production year and week, manufacturing line, and a lot number.  Obviously, these MOSFETs had been made on different lines, years apart.  Did the specs change?  The data sheet didn't reveal anything unexpected.

While the problem still seemed familiar, I certainly never had a bad components before, so this seemed unlikely.  I needed to do more thorough testing.  I pulled out my prototyping board, last used years ago, and to my surprise I still had the exact same power driver circuit configured on the breadboard.  How convenient.

Before I began testing, I traced through the entire circuit making sure everything was right.  While it seemed mostly right, I thought it odd that I had the fuse holder on the output side of the MOSFET, instead of the input side.  It was almost as if I had wired it backwards...

Immediately my brain lit up - the itch was being scratched into oblivion - and a memory long forgotten returned to me.  Now I remembered that I had two versions of the same power driver board.  The memory became clearer in the passing moments, and I could recall that when I received the first shipment of power driver boards, they had the same issue.  I had traced the problem to a couple reversed pins on the MOSFET.  Because it was expensive to have boards manufactured, I struck a deal with the company to have them made again at a discount, reusing the same silkscreens and drill patterns, just replacing the copper layer with the corrected traces.  Visually, the replacement boards looked almost indistinguishable.

Holding the boards at an angle and following the trace lines through the silkscreen, I could barely make out the trace coming from the center pin on the MOSFET.  On the working board, this went to the solenoid connection, but on the bad board, it went to the power supply.

Bad PCB on the left, good on the right.  Can you spot the difference?  Don't feel bad, neither could I...
 In my haste to be ready for the SFGE, I had grabbed PCB's from the wrong box.  This is also one of the challenges of putting such a complex project on hold for a couple years - you simply forget some of the important details.

For the first time in a week, my brain fully relaxed.  The mystery was solved, and it was a simple, obvious mistake, just as I expected.  I should have labeled the bad boards as defective.  Where's my Sharpie...

Day 34 - Thursday:
I finished printing the other speaker mount, and almost successfully printed the middle DMD support brackets.  This last print failed just short of completion when thunderstorms rolled through Atlanta and the power blinked just long enough to reboot the printer.  Considering that these print jobs are taking 10+ hours, I really should have the printer on a UPS.

First try at printing the middle section:  the "tongues" were too large to fit into the groove in the outside panels.  Reprint...

Luckily the print was far enough along for me to check fitment.  While the width was perfect, I found that the "tongues" on the middle section were a hair too large to fit into the "grooves" on the side sections.  After a quick adjustment in the design software, I left it to reprint overnight.

Day 35 - Friday:
Today I head out to the beach for a hard-earned summer vacation.  In between packing and loading the car, I spare a few minutes to check out the new 3D prints.  This time, everything fits perfectly... well, almost.  Seems I didn't account for the cabling pass-through when I added the middle screw mount. 

The middle screw tab won't work with the cabling pass-through - doh!  I'll cut it off instead of reprinting.

I'll simply cut it off, as it doesn't seem necessary.  The three sections fit together tight enough even without glue, and since I plan to epoxy the sections together the entire assembly should be very stable without the additional screws.

I did a quick test fit of the speakers and the DMD panel.  Everything fit perfectly.  The upper slot is for the monitor buttons.

I went ahead and mounted the speakers and test fit the DMD panel, and was happy to find that everything fit perfectly.

Before final installation, I'll paint it flat black so that the mount isn't visible through the acrylic panel.

Amazing little 3D printer, dwarfed by the new speaker/DMD mount.

Week 5 Complete - Time for a break:
After the first four weeks, working up to 16 hour days 7 days a week trying to finish the project (while holding down a day job, no less), week 5 was a blessing.  I didn't accomplish much on the project, mostly I just recovered my strength.

Figuring out why the Chameleon Power Drivers were not working was huge, and really embarrassing when I discovered that the problem was using the wrong PCBs.  At least I wouldn't have to redesign again.  I'll assemble some replacements once I return from the beach.

Even better, having my trusty little 3D printer succeed where my CNC router failed is a big relief.  I was really dreading trying to fix the router once again.

I'll be back in a few weeks with the next update.

Tuesday, June 13, 2017

Modern Firepower returned to the Southern-Fried Gaming Expo

Three years ago, Modern Firepower made its public debut at the first annual 2014 Southern-Fried Gaming Expo.

While schedule conflicts prevented return appearances in 2015 and 2016, Modern Firepower was able to make the trip again for the 2017 Southern-Fried Gaming Expo.  A big thanks to Dan and Joe for making room for Modern Firepower.  An even bigger thanks to Troy, without whom the trip would not have been possible, and Steven, who also assisted with moving duties.

This year's expo itself was a smashing success, with a reported 270+ pinball machines and arcades.  The show was a lot of fun.  If you missed it, be sure to attend next year.

Firepower vs. Modern Firepower at the 2017 Southern-Fried Gaming Expo
Read on for show highlights...

Monday, June 12, 2017

"The Black Knight Rises" - Week 4 Progress

With less than a week remaining until the 4th annual Southern Fried Gameroom Expo, I was now in overdrive working 16+ hour days.  The lack of sleep was beginning to take a toll on my ability to work.  I began to notice that even small obstacles would completely derail progress as I struggled to think through solutions.  I'm beginning to regret the challenging 4 week timeline.

Still, I pushed forward.  This post is longer than most, as a lot happened this week.

Day 22 - Saturday:
The cabinet felt very close to completion, and I was determined to spend half a day and knock it out.  I had applied the Danish Oil on Monday, and after giving it over 4 days to cure, it was time to apply a polyurethane protective coat.

But first I wanted to finish the trim out.  During parts sourcing, I had stumbled onto reproduction Black Knight cabinet side rails, with the dual flipper/Magna-Save button cut-outs.  Of course, being sized for an 80's style cabinet in which the side rails extend to the very back of the cabinet, they were too long for a modern standard sized cabinet with a pivoting backbox.  To make them work, they would have to be trimmed to length.  I also needed to shorten the backbox hinges.

I put a ferrous metal blade on my compound miter saw and got to work.  The hinges were stamped from thick gauge stainless steel, and cut like butter.  The siderails, while much thicker than modern siderails, were still thin and soft, and more than a couple times I slipped with the saw and bent the rails.  I thought for sure I had damaged them beyond repair, but luckily with a bit of straightening and a more meticulous cutting process, I was able to get them finished.

Cutting the 1980's era Black Knight side rails to make them fit on modern cabinet.

Working again on the cabinet, I aligned and drilled the holes for the backbox hinges.  I also had to notch the side rails for the hinge bolts, and the rails were too tall.  I then assembled and tested the side rails and backbox hinges.  This cabinet build is similar to building a hot rod - merging old with new with unique, plus lots of custom fabrication.

Metal cutting finally done, the backbox pivots!

Read on to see how the final build week turned out...

"The Black Knight Rises" - Week 3 Progress

It felt like I was beginning to turn the corner in week 3.  With the fabrication and restoration steps complete, and reassembly underway, it seems I might just make my self imposed deadline.

Day 15 - Saturday:
With the playfield clear coat happily curing without me, I turned my attention back to the cabinet.  I measured and cut out the coin door and bottom panels, then glued it all up.

Clamps, a woodworkers best friend.  Plus heavy stuff to weigh down the bottom panel while glue sets.

Once it was assembled, I was able to then measure for the top shelf and the playfield backstop (not sure what else to call it), cut them out and glued them to the cabinet.

Read on for the day by day recap...

Saturday, June 3, 2017

"The Black Knight Rises" - Week 2 Progress

Week 2 was more challenging than the first, and as some tasks took longer than anticipated, my goal of readying The Black Knight Rises for the 2017 Southern Fried Gameroom Expo begins to slip away.

Day 8 - Saturday:
Troy arrived early and we set off to sawing some wood.  Previously I had hoped to use my 3' x 6' Shapeoko 2 DIY XL CNC router to cut the cabinet.  Unfortunately, over the past half year I've had nothing but issues from my CNC, ranging from bad power supplies to sloppy belts and uncontrollable backlash.  I simply couldn't trust the CNC router for this job.

Especially since I was using expensive walnut.  No paint for this build.

Troy and I spent all day, and got the cabinet sides cut out, and the backbox sides planed and cut out.  The backbox was being fabricated from solid walnut, since the cut sides would expose plywood, and since it was about 7/8" thick, it had to be planed down to 3/4".  For the cabinet I used 3/4" walnut plywood.

Setting up the mobile woodshop in the driveway.

Read on for the day by day recap...

Monday, May 29, 2017

"The Black Knight Rises" - Week 1 Progress

While a lot was accomplished in the first week, a sense of satisfaction is not present.  The road seems long from this end of the journey.

For the  non-electrical aspect of the restoration, I've been referring to the excellent "Vid's Guide to Ultimate Playfield Restoration", written by VID1900 about 4 years ago.  This being my first playfield restoration (Modern Firepower was built new), I'm not qualified to give any tips, merely point you in the direction of the information I've been using.

Day 1 - Saturday:
Though playfield evaluation and parts ordering had begun a few days earlier, I decided to mark Saturday as Project Day 1, since this is where the hands on fun begins.

Troy came over and assisted me in the full disassembly of the playfield.  Every part was tagged and bagged (or boxed).  Plenty of pictures were taken along the way, at various stages of disassembly, to document where various parts should be reinstalled.  We took our time to make sure no mistakes were made.

During disassembly, all the wires were cut off of the lights, switches and solenoids - except for those related to the Magna-Save magnets and solenoids.  We took special care to examine the Magna-Save wiring to reverse engineer the power flow - a task made harder because the flippers had already been forcibly removed and their wires cut free, and the flippers were wired in series with the magnets.  Eventually I came to understand how they were wired from the factory.

With the playfield stripped of parts, it was then cleaned with Naptha, Novus, and Magic Erasers.  This was many hours of back breaking work.

It's a dirty, naked playfield...
Read on for the day by day recap...

Saturday, May 20, 2017

Project "The Black Knight Rises" - Introduction

A few years back, around 2014, I came across a scavenged Williams Black Knight playfield for sale.  Many of the mechanical assemblies had been removed, and the wiring harnesses were cut and ruined, but the playfield itself was in okay shape, plus it had most of the hard to find game specific bits like rails, ramps, scoops, and the plastics.

This Black Knight, destined for the scrap heap, needs help.

I immediately realized that this was a perfect candidate for not just restoration, but a Pinball Chameleon upgrade, adding advanced sound, enhanced multi-ball, full DMD animations, light shows, an LCD monitor backglass, customize-able game rules, and more.  This is the Modern Firepower concept, but now applied to resurrecting a trashed playfield from the junkyard.

Black Knight also presented some new features for me to test and implement in my code.  Drop Targets, Magna-Save, a 3-ball Ball Lock, and four flippers.  Actually, my code already has partial support for these features, though a few tweaks would be necessary to tie them into the game rules.  For example, the Magna-Save would function just like a regular flipper, only the game would now have to disable and enable them as part of normal game-play, plus implement a timed limit on their use.

Parts that I would replace anyway, like the flippers, were already missing from this neglected playfield, so I wasn't paying for parts I wouldn't be able to use.  Plus, since I would completely rewire the entire board to connect it to my own electronics, a damaged wiring harness didn't matter one bit.

Trashed harnesses and missing assemblies... someone tried to murder this Black Knight.

One man's trash is this man's new pinball machine.

I was able to score the playfield for $200.

Another reason I jumped at this Black Knight is that, eons ago when I was first researching how pinball machines work, my buddy Troy scored a nearly worthless Black Knight playfield for about $50.  Though it was not salvageable, that playfield revealed many pinball secrets, from simple things like the dimensions of the wood side-rails, and how pop bumpers, flippers and kickers work.  Having tangible parts that I could inspect and measure, even if they didn't actually work, was game changing for someone who had never been exposed to pinball machines before.

Eventually I tossed that first Black Knight, but not before salvaging the ramps and plastics.

The remains of that first Black Knight playfield:  some metal ramps and rails, a spinner and siderail piece.
Various plastics from that first Black Knight.

Life then got busy, so this playfield has been kicking around for a few years, just gathering dust and generally being in the way.  Now, a mere month away from The Southern Fried Gameroom Expo 2017, I've decided to try the impossible: a playfield restoration and upgrade to the Chameleon Pinball Engine.

Read on to see how I prepped for the project...