Cover art for Interview With Ken Graham, showing a photograph of the marquee for the arcade game Mystic Marathon

Interview With Ken Graham

By A.T. Gonzalez




On December 13th, A.T. Gonzalez interviewed Kenneth Albert Graham via Zoom for ninety minutes. A wizard with hardware and software, Ken Graham worked at Williams Electronics from 1982 to 1983. Williams was not only the leading name in pinball, but also a top American video game developer; their biggest hit being Defender. After buying out Bally-Midway, their biggest competitor, they had a monopoly on the American arcade.

Ken worked on Bubbles, Sinistar, Splat, Star Rider, and the arcade oddity Mystic Marathon during his time in the games industry. Ken used his knowledge to help maintain and repair several classic games in the Houston Area arcade community. He passed away on December 31st, 2021. We will all miss him greatly.


Screenshot of the arcade game Defender.

A.T. Gonzalez (ATG)

Can you elaborate on how much of a success Defender was for Williams?

Ken Graham (KG)

Williams used to be owned by a company called Seeburg which made jukeboxes. Because of how well their SS pinball games were doing, and taking into account the wild numbers Defender was pulling, they were able to buy themselves independent. Ironically, Seeburg went bankrupt a few years later and was bought by Stern, one of Williams’ main pinball rivals.

Williams had an entire building dedicated to producing nothing but Defender cabinets for a year. They made a few thousand a week. The earlier units were made with cannibalized pinball parts, which caused great resentment from their pinball division. The sound boards were plundered from pinball games. The coin doors in the front of the first run (or first few runs) of Defender were the exact same ones being used on Williams pinball games of the time. The later editions of Defender had coin doors made by Chicago Coin.

Defender is something like the fourth-most produced arcade machine of all time and is one of the top-ten grossing arcade games ever. Most of that gross came from the early Eighties. Williams could never live up to the success of Defender.


Can you elaborate on what kind of technology/equipment the art department used to create the sprite animations and attract modes of the games you worked on and games that were made during your tenure [1982-1983]?


We were using a Williams 6809 board. That’s all it was! Which revision, I’m not sure. It probably could have been a modified Defender that we were drawing sprites with. I’m sure of it. I’m sure that’s what it was because they had a few thousand Defender boards laying around.


Why is [the Defender board] called Williams 6809 Rev. 0 anyway? What’s so “zero” about it?


It’s the very first one and was a little bit different from the others.

A few websites think Defender’s hardware is identical to the other classic Williams arcade games, but it’s not, so I classify them differently. I call the Defender one “Rev. A.” Rev. B has the battery in a different place. The graphics and sounds are similar but there’s all of these subtle little differences.

I consider the Revision 1 Williams games to be: Stargate, Joust, Robotron, Bubbles, Sinistar and [Splat]1. Even Sinistar is a little special. It had a special sound chip. It’s quite an animal.

6809 Rev. 0 was licensed to Taito to make a Missile Command knock-off called Colony 7. People think Taito copied from Williams, but Williams sold it to Taito. Colony 7 was one hundred percent Williams hardware.

Moon Patrol and Make Trax have different guts from other Williams games because they were someone else’s stuff. They were licensed from Japanese companies and Williams just slapped their name on it.


Were there any responsibilities on those games we talked about that we didn’t cover in the call?


A little known fact is that I was brought in super late to be a playtester for Bubbles. That actually wasn’t very fun. That’s not a slight at Bubbles, playtesting is just not as fun a job as it sounds. You’re not allowed to leave or take a break. They want to see how you react to the game. I played it for about three hours straight while they watched me like a hawk and took notes. It was unsettling.

Photo showing the screen of the arcade game Bubbles.


Do you know anything about the hardware used in Williams pinball games? Williams Solid Slate, DMD or Pinball 2000 games?


One of the Williams SS platforms was called Williams System 7. Black Knight was a System 7 game, perhaps the most famous one. They used System 7 up until 1984. I don’t remember the specs.

Williams System 7 was succeeded by Williams System 9. I don’t know what happened to “8”, ha ha. Williams System 9 had very similar capabilities to some of the video games they made at the time.

The Williams and Bally DMD and WPC games all ran on 6809-based hardware. I think the DMD games were stacked 6809 boards. The pinball games were all some variation of 6809 until about 1998, I think. Maybe 1999.

The soundchips were some Yamaha thing from 1984. This was all old hardware they were working with. There was nothing bleeding-edge about the WPC hardware. They’re just big, dumb circuit boards. They had eight kilobytes of RAM and were running at two megahertz. Do you have a sports watch? Even the cheapest modern-day sports watch is thousands of times more powerful than any of the Williams DMD games. The fact that those DMD pinball games are so entertaining despite these limitations is a testament to what geniuses the pinball designers and engineers were. I don’t know how they were able to get so much out of so little. These games have stood the test of time. They’re sturdy and fun. People want to play them and they want them in their garage, basement, living room, whatever.

Pinball 2000 is PC-based hardware. Those babies are from 1999 and they can connect to the Internet. I heard they have Attack from Mars tournaments and post their scores online directly from the machine.


I’ve heard you mention more than once that you’ve had trouble repairing Blaster boards? I’ve been trying to film one for a few months. There was one in the workshop at the Game Preserve Woodlands. Why is this game so damn hard to repair?


I classify Blaster as “Williams 6809 Rev. 1.5.” I don’t know anyone else who does. The performance is almost identical, it’s very similar to Rev 1 games (Williams Second Generation) but different enough. You can’t just swap out the ROMs.

They made a few thousand Blasters. Most of them are in a cabinet called the Duramold. They did a Duramold for Bubbles, one for Sinistar, I think, and a Duramold for Blaster. The Duramold Bubbles is very uncommon. Most of them are falling apart.

Duramold can warp and break over time causing the PCB to snap which can require traces to be redone. I had a Blaster board (probably from a Duramold) that I spent two years trying to repair. I had to send it back to the owner in defeat. That was one of the very few video games I wasn’t able to bring back to life. There was another Blaster I couldn’t fix. It was completely ruined. It was torn apart and the metal was extracted from it.

Photo of the marquee for the arcade game Mystic Marathon.


I don’t think we covered what your major programming duties on Mystic Marathon were?


I did the foreground and background art system and did some of the character animations. The title screen animation is all me. That is half a screen of pixels in one refresh cycle. It was one of the best looking games of its time. It is to my estimation the first game that could show thirty-two different colors simultaneously. That didn’t become the industry-expected standard until about five years later.

And I did a couple of other clean ups. The main game programming was mostly done by Kristina Donofrio.

A screenshot from the arcade game <i>Mystic Marathon</i>


You mentioned that you try to keep an eye on all of the working Mystic Marathon cabinets in the world?


Yes. Earlier, Mr. Gonzalez, you said KLOV estimates there’s twenty-nine Mystic Marathon cabinets running. By my numbers, there’s only nineteen still going.

They made three kits: K1 is a Defender conversion, K2 is a Joust/Stargate/Robotron conversion, K3 is a Bubbles/Moon Patrol conversion

The dedicated cabs were the five prototypes.


Do you know why Mystic Marathon struggles to emulate properly in MAME? The physics seem fine, but the graphics are all wrong. The game looks too purple.


Emulations can’t quite nail Williams third-generation hardware (Williams 6809 Rev. 2). They haven’t figured out how to get the timing right. Of the Rev. 2 games, Mystic Marathon suffers the most from this issue. Mystic Marathon actually was the first of the Generation 3 boards. Some parts of it used discrete logic chips that were replaced with ASICs for later Generation 3 games.


Is that why it’s never been re-released?



Another possibility is that a bad ROM dump got out there on the Internet and has been spreading around like wildfire for decades. Since there were only 500-505 of them made, the game was never easily accessible.

The devs who made the home collection compilation cartridges and discs could probably never find the official ROM. Or maybe the producer for the collections didn’t think it was worth porting or emulating. I don’t know.

The source code for Mystic Marathon is probably lost. I certainly don’t have it. I don’t know anybody who has it. Back in those days, the companies didn’t see the value into hanging onto the source code. They could be short-sighted like that.

Another issue is that because the game was a low-earner, they cast it aside. Players either like Mystic Marathon or hate it. The Mystic Marathon audience is small, but dedicated. If anyone ever sees the game, please give it a try.

A screenshot from the arcade game Splat.


Can you elaborate about Splat and the other Williams 6809 Rev. 2 games? (Joust 2, Inferno and Turkey Shoot?)


They’re all pretty rare. I heard that [Splat] had a dedicated cab, a cocktail and a kit but I don’t know how many were made. I heard only ten may still be running. I believe it. It was of a lesser priority. It wasn’t successful. They probably made about two hundred of them.

Joust 2 was delayed for about a year, maybe longer, because they weren’t sure whether to make it a kit game or a dedicated cab. The videogame crash spooked Williams. They only made about a thousand of them.

Turkey Shoot is a funny idea. You’re fighting turkey aliens. When you shoot them, turkey feathers come out of the machine. I’ve never seen all of the pieces for it in one place. They sat on that game for about a year.

I’m not sure if Inferno got a wide release or not. I don’t think it did. I know they produced a dedicated cab. It’s quite rare. Maybe it was a prototype. It’s a neat idea for a game. You’re a fireman in Hell fighting demons and putting out the fires of Hell. What an idea. It had some of the Joust team and even used some of the same sound effects.


What about Devastator?


Some people don’t think Devastator is real. It’s real. They made a video tape promoting it. They wanted to release it. I think that was a prototype that didn’t go into production. Somewhere between three and five were made. Some guy has one of them in his basement. He thinks he’s sitting on buried treasure. He won’t share things.


What were your responsibilities on Star Rider?


I wrote the POST routines used in Star Rider and helped with the code used for the graphic renders. When I saw that screen boot up, it was like saying “hi” to and old friend.


When we called on Zoom, you mentioned “working with Python” on Star Rider. I initially thought you meant Python, the programming language. Someone pointed out to me that Python, the programming language, didn’t exist until 1991. My co-editor theorized you might have meant Python Anghelo. Is that what you meant?


Yes. Yes, I did. Sorry for the confusion.

God, I miss Python so much. Python was one-of-a-kind. He was an amazing artist and designer. He was a genius.

Python was from Romania. He claimed that he had a better education than most people on pinball because he played pin games in a poor communist country before he came to America. He left an animation job at Disney to go work for Williams. He was making $68,000 a year at Disney and gave that up for a $32,000 a year job at Williams. He didn’t care. It wasn’t about the money for him. He took a 50+% pay cut because he thought that video and pinball arcade games were the future of art and entertainment. He called pinball games “little amusement parks.”

Python understood how to make a pinball game from both an artistic and a mechanical standpoint. His desk was always surrounded by art and pinball schematics. To my knowledge, he never wrote a line of code, but understood game and pinball programming enough to carry a conversation about it.

The knight riding the ostrich on Joust? Python drew that! The bubbles on the side of the Bubbles cabinet? That’s Python! Python one of the co-designers for Bubbles. He wasn’t the project head, but was the biggest proponent of that game. He really believed in that game, especially because women seemed to respond to it during the play testing. He thought we were tapping into a female demographic.

Python cared deeply about giving the player the best possible experience. He would always ask “How could we improve this and that and whatever to make the player have more fun?”

Python co-designed Star Rider. Very few websites give him credit for that.

Python always had big ideas. He was pushing to have a game with 3D graphics in it. He wanted the game to be stable and run at what he deemed to be an acceptable framerate.

I helped him convert the pictures we got from the third party that did the CGI renders. Keep in mind this was over a decade before Pixar with Toy Story. If more people saw the game, it would have blown their minds.

Funny story: the third party was taking forty-five minutes per image, especially the Star Sailer. So, Python asked them to increase the resolution. It was taking two hours per image and it wasn’t helping, so I asked them to drop the resolution to one-fourth so it only took fifteen minutes to build a page and it was better than 3D high resolution. We had been going the wrong way. That sped up page production significantly.

The third party was Grey and Associates. If you are old enough you will remember a Levi’s commercial about rocket jeans that was very stylish for the time.

Python also made a contribution to Mystic Marathon. The apple-throwing tree enemies were his idea. Not a lot of people know that.


By the way, I did go to the Game Preserve Spring and applied the tips you gave me. I got to Level 7. I got it all on camera.


Glad they were useful.


Alright, thanks for the clarification!


Thank you for your interest.


Ken Graham died on December 31st, 2021. In accordance with his wishes, The Game Preserve is raising donations for the American Cancer Society. You can donate here.



Ports for Joust, Defender, and Robotron (this project was cancelled).


Bubbles (1982) Attract mode, sprite animation for enemies, debugging, playtester

Splat! (1982) Attract mode, playtester

Sinistar (1983) A.I. routines, debugging, playtester

Star Rider (1983) Start-up diagnostic (POST routine), code for graphics rendering

Mystic Marathon (1984) Attract mode, second programmer (main responsibility was sprite and background scrolling)


Joust Pinball (1983) Playtester, debugger, “knowledge of game code”

TEXT © A.T. Gonzalez




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1 Ken kept referring to Splat as Food Fight. Food Fight is a different game by Atari with a similar premise to “Splat.”

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