Hybrid Solid State Controller in an Electromechanical Pinball Machine

Pintastic New England·video·55m 41s·analyzed·Nov 28, 2023

Analysis

claude-haiku-4-5-20251001 · $0.028

TL;DR

Engineer John Day reveals hybrid EM-to-solid-state controller retrofit preserving original machine soul while modernizing gameplay.

Summary

John Day presents a detailed technical deep-dive on a hybrid solid-state controller retrofit for a 1970s Gottlieb electromechanical pinball machine. The project preserves the EM's original character while adding modern solid-state rules, addressing chronic reliability issues with the mechanical bonus unit found in games like Target Alpha. The presentation covers a two-phase development approach, AC/DC domain interfacing challenges, custom PCB design using KiCAD, and firmware implementation using Microchip microcontrollers.

Key Claims

Target Alpha and Solar City games have notoriously unreliable bonus units that skip bonus, give extra points, and delay gameplay
high confidence · John Day, describing the mechanical issues he solved
The bonus unit replacement eliminated bonus delay and allowed target reset during gameplay, which wasn't possible in original EM
high confidence · John Day discussing Phase 1 improvements
Three machines (two Target Alphas and one Solar City) were converted and ran flawlessly for approximately two years without failure
high confidence · John Day on Phase 1 testing outcomes
EM machines run on 25 VAC with no common ground; the microprocessor ground rides on the AC waveform, requiring optocouplers and relays to interface with DC logic
high confidence · John Day explaining AC/DC domain separation challenges
5V relay outputs rated for 250 VAC at 10 amps failed despite being rated well above the 25 VAC requirements, requiring mitigation strategies
high confidence · John Day discussing unexpected component failures in relay implementation
AC optocoupler inputs pulse at 60 Hz, requiring firmware to detect pulsating signals rather than stable DC logic states
high confidence · John Day explaining firmware debugging challenge with AC inputs
One of the three converted machines is currently in the wild, sold to multiple owners, representing a one-of-a-kind hybrid EM
high confidence · John Day reflecting on the fate of converted machines
Phase 2 design uses a single PCB layout populated differently for playfield and relay controller, reducing manufacturing costs
high confidence · John Day describing Phase 2 design optimization

Notable Quotes

“I promise you will not fall asleep”
John Day@ 0:36 — Lighthearted self-aware introduction to technical presentation
“I didn't want to just rip out the EM soul of the game”
John Day@ 1:31 — Core philosophy: preservation of EM character while modernizing gameplay
“If you had no targets down the score motor wouldn't even spin it would just kick the ball out”
John Day@ 17:24 — Demonstrates how hybrid controller solved blank playfield problem
“The game's tilted so why is it telling me it's tilted and it's not tilted”
John Day@ 10:47 — Key debugging challenge that revealed AC pulsation at 60 Hz
“I've lost it, it's been sold to two or three different friends, I don't even know who owns it now”
John Day@ 18:57 — One original hybrid EM now in circulation among collectors/operators
“The solenoildwould burn and so this eliminated all that because now there's a separate microcontroller doing nothing other than managing all the relay timing”
John Day@ 23:01 — Safety architecture improvement preventing hardware damage from code errors

Entities

John DaypersonDavidpersonJillianpersonTarget Alphagame Solar CitygamePintastic New EnglandeventEl DoradogameFAST Pinballcompany

Signals

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design_innovation: Novel approach to retrofitting 1970s Gottlieb EM machines with solid-state rules while preserving original mechanical components, relay boards, and game soul. Maintains full reversibility.
high · John Day's Phase 1 and Phase 2 designs show intentional architecture to keep all original EM systems intact while adding solid-state capabilities through non-invasive interfacing.
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restoration_signal: Solution to chronic mechanical bonus unit failures in Target Alpha and Solar City games through solid-state replacement of the stepper unit, eliminating skipped bonus, extra points, and gameplay delays.
high · John Day documented bonus unit problems and demonstrated Phase 1 improvements: contiguous bonus counting, no missed bonuses, faster gameplay, three machines tested for two years without failure.
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technology_signal: Adoption of Microchip PIC and SAM C20 microcontrollers for EM retrofit projects, with custom PCB design using open-source KiCAD tool. Demonstrates accessibility of modern electronics for hobbyist/restoration community.
high · Phase 1 used PIC 16F15345 (8-bit); Phase 2 uses SAM C20 (32-bit ARM, 256K RAM, 48 MHz, intentionally 'overkill'). All designs done in KiCAD.
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product_concern: Standard 5V DC relays rated for 250 VAC at 10 amps unexpectedly failed despite operating well below rated specifications (25 VAC, <1A). Issue identified but mitigation strategy mentioned without details.
high · John Day stated relays 'failed anyway' despite official ratings, required mitigation, but presentation was cut off before explaining solution. Significant reliability discovery for others attempting similar projects.
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Topics

Electromechanical pinball machine restoration and modernizationprimaryAC/DC domain interfacing and signal isolationprimaryCustom PCB design and microcontroller firmware developmentprimaryBonus unit mechanical failures and reliabilityprimaryHybrid solid-state retrofit philosophy and reversibilityprimaryReal-world hardware debugging and unexpected component failuressecondaryTarget reset and gameplay modernization of classic EMssecondaryEngineering design phases and proof-of-concept methodologysecondary

Sentiment

positive(0.82)— John Day is proud of his engineering work and enthusiastic about sharing technical details. He demonstrates satisfaction with solving long-standing EM reliability issues. Humor is present throughout (promise not to fall asleep, ball mocking you after draining). Minor frustration expressed about unexpected relay failures, but framed as valuable learning. Positive about community engagement and future plans (potential return in April with further enhancements).

Transcript

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local resident John Day who's been uh more distinguished to pantastic for judging the art of games in the past has stepped out to reveal his true engineering self uh so take it away John well thank you David really appreciate it thanks everybody so um so we get the slides going Jillian that'd be great so uh first off everybody thanks for um for spending the next hour of time I promise you will not fall asleep how's that so uh so uh my name is John day I'm a very serious pinball you know collector restoration dude I've owned a pinball machine since 1985 which I had in my dorm room in college so um so uh so this has really taking me on a very interesting Journey uh today what I'm going to talk about is um a adding solid state rules and capabilities to a traditional 1970s gotle em and we're going to go over all the details um I'm on pin side I'm a pin engineer 77 um with that move on to the next slide oh ah thank you uh so agenda first off um exactly why would you add a solid state controller to an em so I'm going to go over the sort of the reason why I developed this project in the first place and then some of the objectives like you know preserving the EM Soul uh I do a lot of restoration work on EMS solid state games and I didn't want to just rip out the EM so of the game and I'll explain exactly how that's preserved but yet adding solid state rules uh there are a lot of technical challenges uh pinball em machines run on alternating current they run on different voltages uh if you're familiar with solid state games they're all DC you cannot match the two so you have to deal with interfacing between those two domains um also talk about project phases this phase started with just a bonus unit only replacement and then uh later on I uh a second revision of board set was developed to do a full rule set implementation that was the plan all along actually uh we'll talk about all the circuit implementations so um exactly all the circuits we'll go into the schematics and how it um stitches into the uh em itself and then um we'll also uh slides uh and then we'll also go over the uh uh the firmware development so the software that is running on this game and then U like everything if you've ever developed has anyone here developed electronics at all um in their career so I see a couple hands have you ever had a failure that you didn't expect um so we'll talk about that so anyone who has ever developed Electronics you will uh you'll certainly appreciate some of the failures that I I encountered um then we'll go into a deep dive of the implementation and a live demo of the game with that we'll move on to so uh the why like why would you ever do this develop a you know hybrid es em uh controller um so I had two target Alpha machines at the time so I restored both of those and if you've ever worked on a Target Alpha has anybody worked on Solar City or Target Alpha at all and Dave I know you guys have owned them and if you've ever worked on those games you'll notice there's the bane of those games is something called the bonus unit and it's this stepper unit that resides under the Playfield and it basically scans all of the targets whether they're down or not and then that Awards your bonus at the end of ball and those those units are notoriously difficult to work they they are unreliable sometimes they'll give you an extra thousand points sometimes they'll skip a thousand uh they it'll like give you a bonus and then it will skip skip skip bonus skip skip because it's basically scanning the targets uh and it takes a long time and you have to wait for the entire 15 target scan even if you have no targets down so it actually delays the you know the ball time for the next ball uh and um there's another real major problem that this game has has and that is when you drop the drop targets down so good players or if you have a good ball guess what you are actually have nothing to do so you knock all the targets down and now there's nothing to hit you have this blank Playfield and you're just like okay I guess I'll get extra ball and drain it because there's nothing else to hit there's no points on the Playfield and the reason for that is because the state of the targets themselves are actually uh are actually how the unit the bonus unit scans so if it were to reset the targets you would actually lose the context of the bonus for those targets so like the so it wouldn't be able to give you bonus if it reset them so the only way to really solve this is to do a full solid state controller or you'd have to add a ton of em logic so um so I chose the former of the two that next slide so uh here are the design objectives and um first thing I wanted to do is maintain the sole of the EM uh it could have been been really easy I could have just ripped out all the EM stuff and then just done a standard off the shelf like Fast pinball controller or whatever that is not this project so I wanted to really retain everything relay boards score motor all the relays uh player unit everything is totally intact and working on this machine as original um also want to make sure that the the modifications are easily reversible um this game could very well outlive me I don't know so there may be some future owner that maybe wants to bring the game back to an originally m I have no idea but I wanted to make sure that all of those modifications could be uh reversed at some point um if that was ever desirable by a future owner um so we only just remove the um bonus unit and obviously I have that and then um all of the interfaces are just anything that's changed I'll explain what um what's unsoldered and then what's put in its place was all designed so it' be very easy to reverse that bring it back to its original form uh but this drastically enhances gameplay so now you get Target reset set during gameplay just like you do with El Dorado um you get inst unlimited bonus now so you could have 50,000 bonus if you want to if you hit 50 targets down in that in that uh particular ball uh you have things like Target hunt now so you have uh skill shots that are available and those are worth more points those are things that that can be added to the game um you have a much faster game play because now you don't have to wait for the bonus unit to scan for targets that aren't even down um so that's sort of another enhancement that you get as well um and we've added some other things there's um a vacuum fluorescent display that was added in the lower right hand corner can give you some rule guide information um and also like the high scores and all that kind of stuff or or not high scores but the uh free play uh scores are listed there as well and then um also you get a track mode you know EMS are kind of you know kind of a little boring you know when they're just sitting there they're just the lights are on and that's it and now you've got all kinds of animated light shows and such um that you get in the solid state State Games and obviously you get that here as well so next slide um so there are some interesting technical challenges so the first is that um modern solid state games they have a common ground and so um anyone here restore Solid State game um so I was hoping to see a lot of hands that's great so you're familiar with you have um Common Ground you'll have you know 43 volts if it's a valley you'll have a 12volt power supply and then you'll have a down regulator to 5 volts in a typical Bally Solid State game got leaves are like 28 volts DC but it's all the same and there's a common ground but with an em that's not the case with an em you have 25 volts ac not DC um and then you have 6 which that's for all your solenoids and then you have 6.3 volts ac which is for all of your lamps which are both insert lamps and also your Janos Kiss so the microprocessor which runs on 5 volts DC that has to be able to transition from sensing a 24 uh 28 or rather 25 volt AC signal it has to be able to sense if that's there or not and then it has to translate that down to 5 volts so it can sense it and then you have to take 5vt outputs and bring that back to 25 volt solenoid signals or relay coil signals we're all at 25 volts ac so so also you cannot have a common ground so there is no so the ground of the microprocessor is actually riding up and down on the AC waveform of the EM so there is no actual common ground and I'll show in the schematics of how that's implemented so to get to AC inputs I used opoc couplers um very similar to the opto couplers you might see on a on a DMD game and then to get from the DC domain back to the AC domain I used uh 5volt relays and uh so there's a bank of eight 5volt relays in the system and then there are um two optocouplers in the system as well so next slide so this is the AC power supply and and it's pretty straightforward if you're familiar with um any you know standard Solid State game this is a 3. a 6.3 volts uh GI lamp and there's just a standard Bridge rectifier it's implemented discreetly you can see there and then that is using a um mic uh 29300 that's a 3 amp uh low Dropout regulator not that different than you know the like 7805 class game uh Regulators you'd see on a b Solid State game this one has very low Dropout voltage because when you Rectify 3 6.3 volts you you actually lose like 1.4 volts you're already down to close to 5 volts at that point so you need really low drop out on that regulator but that's about it so you know power supply is pretty simple and um that's just connected to the 6.3 volt uh winding of the EM Transformer so the Transformer has a 25 vac and a 6.3 volt winding and it's just connected to that winding at the relay board so U so then there's the optos so this is the way that um let's say for example it has to sense if the game has tilted it has to sense when uh it is the last ball for double bonus so those are two of the sensing signals that are required and those are at 25 vac and so um so there is basically a circuit which is basically a diode a series resistor and you know kind of a load resistor and what that does is that turns on the LED of the opto and then in the 5vt domain the microcontroller can then sense the photo diode and then see whether that photo diode is actuated or not and this is one of the things that um was not actually very obvious like when I was first doing the firmware development on this I was actually getting unreliable results I was like Hey the signal is kind of coming in and out why is it doing that the game's tilted so why is it telling me it's tilted and it's not tilted and what I failed to realize when I was first doing the firmware is it's AC so it means that the opto is is going on and off at 60 HZ so if you you looked at the signal you would see it would be on for you know for like maybe 7 milliseconds and it would be off for 7 milliseconds then on so I had to realize that so I had to change the firmware to be able to deal with this pulsating 60 HZ input in order to be able to detect those inputs so um so just some of the weird things like you know you're used to dealing with DC stuff and you suddenly realize that you have to contend with some of these um you know these AC domain issues so um pretty simple so then the um DC to AC interface so which is you know how do you get back to actuate a relay or actuate the target Bank reset for example um that's implemented with uh four Bank um standard 5vt DC relays and so these are normally open contacts um we bought them in you know Banks of four and uh those were rated it's kind of interesting so you know you buy these relays out of China or whatever like you know Al Express and such and um they have all these great ratings right 250 volts vac at 10 amps so you're like hey I'm in great shape you know I'm only doing 25 vac and it's maybe less than an amp for triggering a um a typical relay coil and um the target Bank resets those are 125 vaac but those are at um maybe an amp amp and a half so so you're well below the rated the official rated current of those relays but I'm going to share something with you um in a few minutes and that is those relays failed anyway and so uh so we'll talk about that and maybe how that was mitigated so um the relay outputs um these boards are pretty cool they have they have isolation I didn't use that but uh they do have status LEDs you tell when the relays are asserted or not and then here's the eight signals that you have to connect to and so it is the 10's relay so that's the L circuit um there is the hundreds relay which is the m relay if you're familiar with that in the head and then the thousands relay which is the n relay um and then there is a extra ball signal that you have to connect to in order to latch the extra ball condition so that you'll get you won't advance the player unit and then there is a another um solenoid that you need to actuate for special if you want to give the give a um player a an extra game and then um then there are some other additional outputs that you need to deal with so one of the magic of all of this is that this em the solid State Controller intercepts the ball trough switch so if you're familiar with the or goly BMS there is a ball trough switch that the ball resides in and that's what kicks off the score motor to advance the player unit to the next ball and that is intercepted so the microprocessor is scanning that switch now and now there is a relay that is in the relay board that will assert that switch locally so now the microprocessor can do whatever it feels like the ball is drained it can do animation for bonus it can tick off all of your bonus and the EM thinks that the ball is still in play right now actually and then when it's done then it kicks off the um ball trough relay and then that now causes the score motor to advance player unit to advance and now the the game moves on to the next ball and the last two which are super important and one of the major reasons for this controller in the first place is to be able to reset the five Target and the 10 Target bank and um and I'm directly controlling those so those solenoids are in Direct Control of these relay you can reset them at any time you feel like it so um so there were a couple phases of this project and um if you're familiar with um engineering a lot of times you um it's always a good idea to do proof of Concepts and sort of break a problem down into you know multiple phases because sometimes if you tackle the problem the whole thing all up front um you may be discouraged might be a little bit too much to you know to so we always plan on things like revisions you know rev a REV B this was a phase one and a phase two of the project so uh phase one was basically bonus unit only so the objective there was to eliminate the mechanical bonus unit Implement a solid state controller and that and then play the game and just see does it fail does it have reliability issues I mean how well does it work like what do you learn from that so the whole that was the whole objective there so that was a custom board I'll show you what that looks like in a minute it was powered from the GI circuits and then there were two onboard there was one onboard opto which was used for the scanner if you um if you've looked at like a Target Alpha the original bonus unit there's a solenoid that advances the 15 positions that kicks that um that um it's basically a stepper unit so you know steps through it so that particular solenoid input is the opto input for that controller so it knows when the relay board is advancing to the next Target and then there was two other relay outputs so there's the opto input and the two relay outputs and those emulated the switch contacts that you had that it was scanning and they emulated the 15th position on on that bonus unit there's a set of uh read set of uh switches that you'll see switch contacts and when it hits the 15th position they they get closed and that's what causes the game to finish bonus and advance to the next ball so there's a relay that basically emulated those contacts and a relay that emulated the wiper that is wiping across the 15 positions um and that was it so um that actually improved the gameplay quite a bit so this proved out power supply the AC to DC domain and DC to AC domain so it kind of proved out all of those circuits and then it made a significant Improvement in gameplay because like it was cool like let's say you have a bad ball and it drains and if you ever play that game by the way it sucks because it drains and then it goes for 15 positions it's almost like it's making fun of you you know and it's like it's like dude I just want the ball to come out so I can play another one hopefully better next time and um so it eliminated that issue like right off front so like if you had no targets down the score motor wouldn't even spin it would just it would kick the ball out and then just spin to advance the player unit that's it so it was much faster game time it also eliminated um the bonus count was completely contiguous so um so if you had the if you had like targets if you're familiar with the way the scanning works it's uh it's done in a linear fashion so you might have some targets down some targets not down and so in the original game it would go you know bang bang and then it would do nothing because you don't have any Targets down and then all a sudden bang and then bang bang bang it would Al it's almost like it was doing Morris code sometimes you know um so uh so it eliminate all that so now when it decided it was going to dispense bonus it would just bang out the bonus all in a linear fashion regardless of where the targets were that had fallen um it guaranteed that um that you didn't miss any bonus because it's dead on so there's no more like missing bonus or getting an extra bonus which again is common in these games and uh and then uh it would eject the ball basically after every five targets down which was really nice to it eliminate one extra oneir score motor spin as well so uh so I actually had two target Alphas at that time and I had another friend he's not here actually but he had a a Solar City and we converted those three games to run this bonus unit hardware and we wanted to run it for a while see if there'd be any failures so we kept that in the game for about two years and uh they work perfectly and in fact one of those Target Alphas is out in the wild I've lost it it's been sold to two or three different friends I don't even know who owns it now so someone owns a game with this bonus unit in it it's a one-of a kind I don't know if they're In This Crowd right now but uh it'd be interesting to see who owns it these days so next slide this is the bonus unit schematic and um just to go over this briefly this is a AC todc power supply very similar to what I showed earlier um and then there's a single scan opto so you can see that opto that's implemented there and then uh there is the um score and 15th position relays you see those two relay outputs there that emulate the switch contacts and emulate the um wiper scanner essentially and then there are 15 DC's Target switch inputs and you can see those down at the bottom and uh those all connect to a uh microchip it's called a p 16f um I think it's a 15345 so uh full disclosure actually worked for micr chip so as a as a apps engineer so so I kind of get the I guess I get the tools for free or whatever so I didn't had a lot of experience with these parts too so uh so anyway so that um so that was really a fun project got that up and running ran for about two years or so and then uh um and then at that point was starting to really plan out the next phase once I had some good confidence that this was a solid way of dealing with an em so um next slide you'll get to see some pictures of it so I used a tool called key CAD anyone here use key CAD at all do board designs so yeah it's an awesome tool so uh this is all done in kycad it's free tool if you ever need to do a PCB Des highly recommend it it's called key cad.org um and then if you look at the next slide you'll see it actually implemented in the game and it's kind of cool like the 3D pictures represent what the real thing is which is kind of fun too um but to show you some of the wiring here you'll see the 6.3 vac so that's just connects to a GI lamp for example and then the scan that's the solenoid that would that would increment the stepper that's just that solenoid connection and then you see the relay connections and the upper one is the 15th position those are all the wires for the switch stack that's at the 15th position when it hits the end of scan and then the lower one is the two contacts that's the represents the wiper contacts um and then you have your 15 targets you see at the top so that's what the wiper contacts would have been connected to and you'll see that those are connected there which is pretty simple so you can see how this is not really that invasive in the game you know you can see they just tap on the six the 6.3 vac the target the bonus units removed but the wires that were connected to that now connect to this board and then um same with the switch Stacks are connected to it as well so so that was phase one and then uh at that point we kind of moved on or I kind of moved on to phase two so which was a full hybrid with custom rules and this was really where I wanted to take the project in the long term so now I got a lot of confidence in you know the circuits you learn a lot from implementing like a REV a you know you kind of learn like what you do differently and so now that you know you got that experience and time to move on so um this in this particular case I ended up deciding to do a single print circuit board design that could be used for both the Playfield and also for the Relay board and I'll explain that architecture in a minute but um one of the things if you look at a lot of modern games like a like a Stern you'll see that there's a data cable basically it connects between all the spike boards so I Implement something very similar so there's a simple rs45 data cable that goes between the Playfield and the relay board itself and that really reduces the number of wires cabling is nice and simple very easy to diagnose and there was some significant advantages when writing the game code because now the real-time things like asserting a relay where let's say if you asserted a relay or you turned on the selenoid to reset the drop targets if you halted the code or the code went hey wire the solenoid would burn and so this eliminated all that because now there's a separate microcontroller that is doing nothing other than managing all the relay timing and so you can now develop all your game code on the primary Playfield microcontroller and now um You can halt it you can screw up the code whatever you want and there's no risks of you know causing your game to catch fire so I think that's pretty important so um so it was a single PCB and that was done mainly because it saves me some cost that way I get the pcbs manufactured and I can just populate them differently based if it's Playfield or if it's the relay board and I'll show you that in a moment uh 45 between them use an old USB cable so I don't know if you've ever cut the ends off a USB cable but it's a nice data cable with power so just reuse that it was perfect um and then the Playfield controller scans all of the switches uh it drives the RGB LEDs so for all the um all of the animation and such and then it has a apron display which we show in a minute and that shows you game status and um has like a track mode type of information uh uh where the replays are set all that kind of stuff is there so and uh the relay controller itself contains the uh DC power supply we'll go into the details of that in a moment um scans all the AC isolated which is tilt and ball relays um or last ball which is basically ball number three in a three ball game and drives all the relay outputs um and also provides all the timing there's also a place for a MP3 player that's there as well and um so we I do plan on adding uh uh MP3 so we'll have a speaker in this game and be able to play you know background music and all kinds of call outs and stuff like that so if I return in April uh I would expect you'll see quite a few modifications and enhancements uh um by that time so so this is the Playfield controller and uh the main microprocessor is a at microchip it's called a Sam C20 which is a it's a 256k rmm z plus part runs at 48 MHz way overkill for this application so it's totally Overkill which is appropriate for an Em Right if you're going to put a micro processor you should put a big one in there and uh so um so it it basically scans the 10 drop targets that you see in the upper Port of the Playfield it scans the five um lower drop targets so those are all just direct signals into the microcontroller uh it has pop bumper and standup switches so it can see if the standup switches have been hit by a ball or the pop bumper is asserted um it scans the rollover switches on the left and right for special and extra ball and then it's scanning that ball return that I mentioned earlier has the ball returned then it knows that the ball's no longer in play it can dish out the bonus so it can you know send out the bonus do animation whatever else it feels like and then when it's done it can close the ball return relay at the relay board which will then Advance the player unit and continue the game so it also has um some outputs too there is a uart which is the uh display uart in the lower apron and um currently I'm not doing a ton with that that has some statistics some internal variables when the game's in play it tells you the uh scores are required for a replay you know typical stuff that you would have hardcoded on a game uh there's some rule um um sort of in track mode there's some uh some rule suggestions you might see there as well that pop up so I think there's an opportunity to do more there and then it also drives the ws2812 uh B LED so that's how it's doing all of the color generation for that and then it's got a rs45 which is basically that USB style cable but it's just a standard serial cable and uh that connects to the relay controller which I'll show next and the relay controller you'll notice that the print circuit boards the layout is the same you'll notice they're populated very differently so you'll notice on the left you'll see like the 15 pins up top I'll show you the details of that in a minute but you can see how the connectors are populated differently you might notice a couple jumper wires are in there as well so I I kind of designed it so I could just repurpose this board for both purposes which you know kind of helped in some of the manufacturing costs so and now um this is the relay controller so this controller so Playfield controller was mounted to where the um where the original bonus unit was the relay controller is mounted down on the relay board next to the Transformer so that's down there and the relay controller itself has two inputs those are AC so they have to be optically isolated and that has to know when the last ball is occurring so that it can properly show double bonus so that's really important it also needs to know if the game's tilted or not that's useful information also so it needs those two bits of information from from the relay board in order to make some decisions um then it um also has it connects you can see through 485 to the Playfield controller and so uh that we showed in the previous slide and then it has outputs so uh first off you'll see the uh 6.3 vac lamp circuit which is the power supply so that's how it's generating 5 volts and where all the 5 volts is available for the Playfield as well and then that also contains the eight relay outputs you see and you can see you know two sets of four and just to review those one more time it's you know the nml which are all your scoring um those all go directly to the head and then it's you know ball return Five bank reset 10 Bank reset and extra ball and special so those are all your relay outputs and that's it so so these are um the detailed pinouts or pins you know connector assignments just to just to kind of make this presentation complete and uh we'll start on the left with the relay board and what you'll see on the relay board is um you'll see the uh chip ol up here on the right is a rs45 transceiver driver and you'll see the you know four pin connector it connects between the Playfield and the um relay PCB and then you'll see a last ball and tilt those are the um 25 BAC signals to know when it's the game's tilted or if it's in last ball mode so let's go through the optos the opto isolators that you see there and then there's the 6.3 vac which is the 5volt power supply you can see that regulator down there and then there's two connectors which have four outputs on each and each of those Drive the relay boards so those are your four outputs for the Relay boards that map to that uh there's another connector it's not shown populated here but it is on my game which which um does the apron display that you see and you'll notice some uh USB connector like why would you need a USB connector and the reason is because um we have plans to be us using a dfr um two I think it's 299 which is an MP3 player so we'll be populating that writing some firmware drivers for that that'll give us the ability to do call outs and you know speaker and do all kinds of you know fun um solid state music whatever else we decide to do there so that'll be fun um on the right you'll see the Playfield controller and so the Playfield controller again it's the same PCB you'll see that like the regulator's not populated um you know a lot of stuff is not populated there um it doesn't need the optoisolators but U same microcontroller is there but now all of a sudden the the 15 pin drop carget connector is populated uh and then you'll see the driving to the RGB insert LEDs and so that's where the RGB inserts are connected um that's where the again the uh 45 interfac is the upper right and then this is where the standup targets connect and the rollovers and and and pop bumper uh input switches connect as well and that's it that's all the hardware so uh that's involved for this this so and uh this is the actual um Playfield we're going to we're going to get some cameras in here um that can show some of this stuff live but this is just a quick snapshot of the uh Playfield controller PCB mounted um you can't really see it very well but this is that 15 pin connector that was originally to the bonus unit so it's connected down there and then you'll see like the pop connector you know for the pop bumpers and standup targets there that connector there is for the um ws2812 SEL your RGB LEDs and then uh same for up that connector as well so pretty straightforward actually so and next slide thank you it turns out that the inserts needed some custom boards too you know once you start designing boards sort of your life becomes designing boards it seems so um so one you may as well keep going right so there is uh two different sets and unfortunately gotle did not use the same spacing between the 10 bank and the Five bank not may not be very obvious to you but it will be after this seminar now and you won't be able to unsee it but it turns out that the top 10 actually have a 1in spacing and the lower five have a one and a/4 inch spacing so I had to do two different pcbs so you'll see the 1.25 PCB um and that just you remove the lamps and then you just screw that PCB down and you're up and running very similar to the way like a modern Stern game would would implement it and then you'll see the two pcbs at the top which represent they're in series and those represent the uh 10 drop targets there and then there's a bunch of single um insert um RGB LEDs and those go under the extra inserts in various places that you couldn't really have them collocated so um and this is the the actual um series Drive of it when you drive these LEDs you send a like a data packet out and that data packet is formatted where you send the data for the last LED first and then it just gets serly sent to each LED down the down the line and that's how it works so you have to know what this order is in order to get the programming correct in order to get all the right places and this is how it's wired on this game so it goes to the five Target first then the you know 10 Target right 10 Target left then you know extra ball left and right and then special double bonus and shoot again so those are all of the inserts that we have RGB control over which is pretty good and I I think it actually might exceed a modern Stern has I think a modern Stern has like 13 rgbs so I think there's more than that on this which I think is kind of hysterical actually so with that uh we'll move on to the next one this is the actual um schematic itself and uh so again you'll notice that power supply is kind of carried forward that you'll see in the upper leand corner just from the original you know bonus unit you know like phase one implementation so that just got carried forward same thing with the optoisolator that got carried forward as well you'll see the same Target inputs you'll see in the lower Le hand corner there that all go into you know microcontroller inputs and then um you'll see in the upper right hand corner that's the rs45 driver chip uh that connects to a a uart connection on the microcontroller um I have some relay stuff that you see there those relays weren't needed so I I kind of envisioned that they would be needed but in the end decided they weren't even needed so they were never populated in either of these boards but um they're on the schematic listed as do not populate and then you've got outputs to like the ws2812b and then you'll see the MP3 player at the bottom that we have a place for it and uh expecting to kind of work on code on that probably this winter so um so pretty straightforward not a lot to the schematic there um you know take a look at it's not really there's really not a lot of Active Components it's just the microcontroller regulator and rs45 transceiver and that's the whole thing really so there's not much to it so so let's talk about how you connect to what so now you've got the pcbs you've got the RGB LEDs but how do you wire it all together so we'll talk about that next and so first thing the 15 drop targets the standups you know rollovers pop bumpers all that stuff those are all disconnected from the Playfield so anything that is a switch input like the drop targets a rollover pop bumper B relay the original connection is UNS slaughtered put some heat shrink tubing on it and then zip tied it so it's still there not no wires are cut or anything but the the solid state controller has to take has to own those because you got to bring it into the DC solid state domain so all of that is um this connected so there's roughly I'm going to say like 20ish or so um connection points that you have to unsolder and then you know solder onto wires in some case you got to run your own wires essentially to those switches um all the insert lamps were removed and then uh the RGB boards that you saw were just screwed down in their place and then next thing then you're then you're done with the Playfield believe it or not that's all that's involved and then now you pop the relay board out and then uh you have to connect the LMN extra ball and special relays those are all in the head actually so there's a wiring harness that goes into the head connects to those relays directly and then um then you have the five Bank reset 10 Bank reset and and um the uh ball drain you know the trough switch those all are on a Jones plug that you have on the relay board you just tap into those and then uh lastly you just connect to the Five bank and 10 Bank um which are on the Jones plug as well and you're up and running and that's it and the 6.3 volt AC which is right there at the Transformer so that's all the connections so on the relay board there's virtually there's like no wires cut whatsoever you're just kind of ta in onto the existing nodes that are there and then in the play field there's roughly about 20 connections that were disconnected and wires were provided separately so with that this is what the relay board connections look like so you can see the board there um that's mounted and you can see the the um relays the two sets of four relays and um you can see some of the wires that sort of go along there you can see a couple of them that tap off to the Jones plug on the five and and 10 Bank solenoid connections uh and then it the last ball relay is the one in the lower um you can see that lower right hand corner it just connects to the relay coil itself just Taps right on top of it so it can monitor if that coil is energized or not so it knows the state of the game so and that's it and in the head connections are very straightforward there's a relay common in one of the Jones plugs you just kind of tap onto the soldering point of the Jones plug and then same thing with you know LM andn those are all available on Jones plug connect nections and then in the case of Target Alpha and Solar City there's a jumper between where you adjust between extra ball or special turns out those are the places that trigger those solenoids so or relays so all you have to do is just connect to those and you're up and running so this is what the Playfield looks like underneath it after it's completed uh so you'll see the controller board there uh which is where the bonus unit would normally be mounted but you can see all the original em wiring all that stuff is all there nothing's really removed uh and if you look at it closely enough you can start start seeing where the uh where the RGB boards are mounted you know underneath the um underneath the inserts and then if you look at it even closer you might see situations where you know the EM wires for the switch are disconnected and then you can see a couple of wires that are brought in its place so it can scan it but that's kind of all it's involved so and um I I I Dave suggested that we go into em who here reads em schematics regularly I love that so I guess that's why we're all here so uh this is the got Le BM schematic for a Target Alpha and I just want to show the points where things are tapped in so uh so you can see that for the 10 and the 100 point you just have to connect to you know the common hot that's an energized when the game is ball in play and not tilted and then you just connect to the other side which is the relay itself so in some cases you're just going straight across a switch like there's a thousand Point switch on target Alpha so you just have to get across that switch you're up and running um in this case I just got it all at the head because at the head you know the Playfield you might remember on these games there's a smaller Jones plug from the Playfield directly to the head on these games and that Jones plug contains actuation for like the tens the hundreds and the thousands so I'm just kind of stealing I just connect right to the heads a lot easier to get to it there and then you can control each one of those relays so that's your fives tens I think the thousands the same way I just ran out of space on the slide but it's done the same way and then with extra ball and special uh those are oops I'm sorry go back one slide thank you so uh with extra ball and special same thing those are available on the head so there were tap points that were available and that just shows you where those are tapped in on that Jones plug and then again they get to the common um you know power when the game is is on and and ball and play is is valid so and then next slide and the last is you have um the five and not second to last that is you have the 10 and five Bank drop Target reset relays so this is 110 volts so this is probably the most dangerous part of working with something like this because this is line voltage now and um so in this case I actually did disconnect I wanted to make sure that like the score motor was no longer powered and I didn't have to worry about like back feeding or anything like that so this is one situation where I disconnected the the uh 110 from from the path going to the score motor cuz cuz I wasn't didn't need it and then just biased these relays off of that and then connected directly to the Jones plug cu the Jones plug itself has to provide 110 to the Playfield in order to actually actuate those solenoids and so I just tapped right onto the Jones plug disconnected it from the score motor which is what would normally access that and then the relays now take over that connection so and then I think there's one last thing which is ball return and as I mentioned earlier the bonus unit's removed right it's not there anymore and it turns out that ball return is a lot of that complexity in this schematic that are all those 15th Point switches that I you know the 15th position switch I mentioned earlier that's part of your ball return mechanism and so when you remove the ball return mechanism you sort of return removed all of the connections to that already so it was quite easy to just tap onto the net result of that at the Jones plug and be able to emulate the ball return so and then the last thing oops one more sorry back so last the last ball and tilt optoisolated inputs so these are just optos that you have they connect directly to the Tilt hold relay and the uh last ball relay so they just tap onto there now you know when it's last ball you know when their tilt occurs and that's it that's all the wiring so for the game and this is the firmware development so uh there's a uh this is a mlap x IDE and a a c compiler that works for the arm parts and a simple snap debugger and uh basically all the code was developed with that and uh and so you know it's a standard IDE code's all written in standard C it's 100% like groundup so it's just something I wrote myself um I have a a CO do you mind if I introduce you so I have a Cod developer in the audience here I'm Dave Henry so you might notice that there is a solar city that is next to where the target Alpha is and uh we converted Dave's game in the last month so we'd have two games here and uh Dave's actually helped me with some of the cool new rules as well so the two of us are going to kind of co-develop the code going forward so um so anyway so that's the IDE that we used for you know all the source code development and stuff like that this is not based on any like standardized game platform whatsoever it's it's a pretty one-off unique thing so um so that's it and I think at this point oh let's talk about failures so so the game was uh running for about four months like I I got this game running in I think it was January of 2022 so roughly a year and a half ago I was so excited like it actually worked right off the top like perfectly and I played it was having a blast with it and then all a sudden like the hundreds weren't scoring all the time like you know I'd be like wait a minute I should get 300 points there and I got like 100 and then it would like not score anything and then it would score at some days and not score at others then the thousand points started doing that too and I'm like what the heck is going on with this and you know the controller was fine and you know put some scopes on it I'm like I think these relays failed but why would they fail you know I mean I'm not they're not really um loaded much so I had the m and the end relay both start giving me trouble after maybe about four months maybe probably maybe 500 games or something like that but the load is only 1 amp at 25 volts but the relay says it's good for 250 volts at 10 amps so why are these relays failing I mean I'm only using at 10% of their rating um so I actually disassembled the relays and and um this is a microscope um picture of it and the contacts were burned so that's why the relays weren't working and um here's one of the interesting problems that I just had never thought about and everybody familiar with the flyback diodes that you have on solenoids and relay coils and and if you know the reason for that I'll just explain a minute the physics why you need those and that is when you when you energize a coil whether it's a solenoid or a relay coil there is a magnetic field that surrounds that coil and Life's good when you energize it but the problem is when you de-energize it the coil collapses the um that energy collapses and what it does is the coil does everything it can in its power to keep that current flowing and what does that mean it generates whatever voltage it can to do that it's how your ignition system works in your car that's how your spark plugs work they're just a coil it gets fired and uh and the Magnetic collapses it'll generate 30,000 volts if it has to to keep that current flowing so that's why diodes are added there so the diodes are basically called flyback diodes and what they do is they short that voltage out because it's in the opposite direction that's great that works in a DC system but in an AC system you cannot put flyback diodes in that's not an option so instead I used a uh did some research and ended up putting a an RC snubber circuit um and it's in this game so far I think this game has exceeded the failure time of the latest failures but I don't know that for sure we'll see if it makes it all through pantastic without relay failures so but there are RC summer circuits that we added or added to each of the re of the uh coils I didn't want to do that for the really high voltage coils like the 110 so I put a a mauve there a metal oxide veristor which is the same thing you have on your um typically on your line filter if you've uh if youve ever taken a part a solid state game you'll see a mob there so that was it and uh I think we're probably on the last slide so at this point I'd like to move on to uh demonstration and I'm just going to if we can get the screen switch that would be great thank you and so everybody can see a track mode that's happening right now so you can see all the you know lamps are flashing um you can see that we have U display information the lower right hand corner um so that's pretty good so now we'll hit reset and you can see this is a standard em it's doing all the standard reset stuff that you would see score motor spinning all that kind of stuff I'm not a good enough player to do this accurately so I'm going to probably use my finger to show off some of the features so first thing that you'll see is a flashing blue here and that's indicative that this is a skill shot and so if we hit that skill shot oh this is that's too funny there it is and that's funny okay so I missed the skill shot there we go and so now that so now it's reset and um you'll see that that Target resets after the fifth Target drops and now you'll see the extra ball is flashing and so if we hit that so now I'll get extra ball flashing here and this is actually going to energize the extra ball and now um now we're going to drain the ball and you can see an animated bonus so everybody see how the targets all turn green there so you saw everything turned green so now I'm going to try to get this correct so now you'll notice that I I got the skill shot now so now this this has turned um blue now instead of red um or was purple I guess before and we get a second skill shot which is pretty cool now so now I'll hit this second skill shot and now um we'll get a second a third skill shot so we could now hit that third skill shot if we wanted to and it'll continue on the skill shots continue on where you're getting an extra you know I think it's 4,000 points is that correct Dave 4,000 for the first 4,000 for the second and then 2000 beond oh there you go so that's the rule so thank you and so uh so I think I'm only going to get so you'll notice you get the 300 and you'll notice I'm getting 2,000 points now for the skill shot so now let's say I screw it up so it's down here notice it's moved from the upper Playfield now to the lower play field for skill shots but let's say I screw it up and I knock this one down and so now it's over so the skill shot's done I only got 300 points for that and now I'll drain it and you'll see the you'll see the animated uh so now let's show some other things so now I'm going to I'm going to just so now I just did a sweep so so every Target was now so try that on a regular em so we got all 300 points for all 10 targets we got 3,000 points like we were supposed to you'll notice the targets reset instantly when the 10th Target and it continued like sending the score out it was fine you know so it did that immediately and um and all of that's remembered too by the way and you'll notice that now we have extra ball and special which are part of the original so we got our knocker like you would expect and then you know I could get my uh extra ball here as well and now I'll drain and watch the uh let's watch the animation so if you watch the um so see how it see how it's doing green so it does a animation countdown which I forget what games got Le did can someone named some of the games that do animation during bonus EMS I I know I've seen it the ladder counting down it's like a ladder countdown yeah so it's kind sort of emulated like that exactly so um so that's that's kind of that's a good demonstration of the of the of the rule set and as I said you know I'll do a quick uh and again you can see it resets instantly and you know we can knock it down a second time if we want to and keep going on and on and uh some other things you know we animated when the target drops flashes um goes into the purple State all that kind of stuff so um with that I think we want to uh do we want to yeah I got five minutes okay 10 okay so um do we have time to show the bottom of the Playfield or should we do questions what would ah thank you so um so here's so you can see the controller here and uh there is a status LED that sort of gives us some indication about you know what's going on in the game and stuff like that there's another one down at the bottom as well I didn't really talk about that but you can see the connections are really really simple um if you follow some of the wiring like this is the cable that goes to the um that goes to our uh apron display just three wires uh you can see some of the RGB inserts here that you'll see you know each of the inserts you'll see the custom board down here for uh the five drop uh Target Bank drop and you'll see uh similar boards down here where the uh 10 are and you'll see two different boards that are wired in series with each other and then here's an example of like where we take off this is the B relay so I think a lot of folks are probably familiar with the B relay if you ever worked on a got Le I'm sure you've dealt with this one and and just two of those contacts are taken that's it just remove two of those we get two of the outer contacts and now we know whenever the pop bumpers are getting asserted so that gives us the information about when the pops are asserting um very similarly you'll see our standup targets again this is another good example of you'll see the wires that are you know taped off to the back and then you'll see the two connections to the uh standup Target so that gives us when the standup Target gets hit you'll see a similar standup Target connection here as well and then um some other places that you'll see where it gets stitched in is um you'll see like these rollovers here so if you take a look at the those rollovers you'll see again you know some custom wires the original stuff is is you know tapped back here you'll see how it's you know how it's uh heat shrinked back and then you'll see the original wire there as well and then uh lastly there is uh you'll see this is the rs45 cable that you'll see and that just sort of snakes down here and then that connects down to the lower relay board and now once we have the relay board you'll see the uh controller and the relay board and you'll see that's doing a rgnb that means that there's you know proper connection thank you I got it so oh yeah yeah no worries so you'll see the rg&b uh connector there you'll see this is the status LEDs for those optos which is um last ball and also um Tils and then you see the connections here to the um relay boards so you'll see the two different relay boards and if we were to um do a rollover for example that's involved with that you can see the LED flash you can see the LED flash down there you know with one of these relays that's getting actuated and you can see a couple of the connections that are that basically connect if you sort of follow it closely enough you can see how the wiring connects to a couple of the Jones blug connectors and you'll also see the cable down there um you'll see a cable down there which is the one that goes up to the head and connects to the LM andn relay so uh but that's it I mean the rest of this game is all completely preserved um so I'll show I'll show you an example of like so this time if you watch the score motor so watch this notice I just did you know 500 points notice the score motor did not spin but now I'm going to do now I'm going to do a regular em one so there are still a few switch contacts that we left as em connections and you'll see the score motor spin in order to dispense that code but if it's a solid state controlled then um score motor doesn't need to spin for that so those are the shinest seen oh are they thanks yeah yeah you know it's a OCD it is OCD yeah I've been accused of that in the past yeah yeah I think us OCD people know each other when we see each other in the field so I'm going to stick in one remark revealing something I've never revealed before that I've kept secret for over 50 years in the mid 70s Williams was thinking along these lines they were they had a whole experiment of changing over to ID State module by module probably inspired by the way jukeboxes if you might remember from about 1968 to 1976 jukeboxes changed to solid state module by module and Williams had been thinking of that same thing on pinball like let's do a Credit Unit that's just a modular Credit Unit and then let's do a modular score display later and and then work in bit by bit so this is very very much in that spirit so yeah Steve cordek would approve of what you're fantastic yeah I I have a feeling if the got Le guys were here they'd to proove it to yeah it was a nice way to kind of transition it you know I mean it's uh the next one dick Dick Hamill's doing the next seminar by the way um I've actually implemented seven games with his codebase so um you know I can't wait to see his presentation I'm a huge fan of that so if you have time highly recommend you attend the next uh the next session so and you'll be hanging out most of the weekend in the custom game room yeah yeah absolutely so answer questions get chance to play it too cuz you know and hopefully it continues to work hope I don't have any more relay failures but you never know it's pinball after all right all right thanks very much John thanks everybody appreciate it