Thursday, November 26, 2015

Mirco's PT-109 - the first microprocessor-based video game??

The introduction of the first microprocessor games in 1975 revolutionized the coin-op industry. For both video and pinball games it lowered production costs, simplified the design process, and allowed for additional gameplay options and diagnostic functions. For pinball, it had the added benefit of lowering shipping costs by substantially reducing the games’ weight.
(NOTE that with pinball games, the transition to solid-state technology [the use of semi-conductor-based components such as ICs] and the transition to microprocessor technology generally occurred simultaneously, unlike in coin-op video games, which had used solid-state technology before the transition to microprocessors)

As most of you probably know, Midway's Gun Fight is almost universally acknowledged as the first coin-operated video game with a microprocessor. One thing I have learned while researching video game history, however, is to be skeptical of any claim that a video game was the “first” to do X. Such claims are often made on the basis of little or no research and turn out to be incorrect, or at least incomplete, when the evidence is examined. Such is the case with the first microprocessor videogame.

I posted about this subject earlier and suggested a few possibilities, one of which was Mirco's PT-109, which was introduced at the same 1975 MOA show as Gun Fight. At the time, I was not entirely certain that the game used a microprocessor. Since then, I have found that it did use one – the Fairchild F-8 (interestingly enough, the F-8 was also used in two other early microprocessor video games – Jerry Lawson’s Demolition Derby and Innovative Coin Corporation’s Spitfire). I have also unearthed a little more information about the game, including the identity of its designer, Cash Olsen. In this post then, I take a closer look at the game and discuss some other early microprocessor coin-op games (for more information on Mirco, see my earlier post)


That Mirco developed one of the first microprocessor video games is not surprising. Not only did it have extensive experience developing microprocessor-based test equipment, but a number of its employees had come from Motorola, where they had worked on its 6800 microprocessor. Chief among them was Mirco’s President Tom Connors. Known as “Tiny” because of his immense size, Connors had headed Motorola’s Semiconductor Products Group. Surprisingly, however, PT-109 did not use a Motorola microprocessor. Instead, designer Cash Olsen, chose to use a Fairchild F-8, due to its development system, sales support and ability to transfer large amounts of data efficiently. (Olsen 2015; EDN 3/5/76). Integrating the F-8 into the game’s hardware was a challenge. Olsen recalls that F-8 consisted of separate chips to support memory, Input/Output, and other functions. In addition, PT-109 was one of the first games to make use of a new component called a Field Programmable Logic Array (FPLA) – an Integrated Circuit whose logic of “ands” and “ors” could be reprogrammed in the field. In total, the game used about 300 chips – 50 for the video and the rest to support the microprocessor (Olsen 2015). If creating the game’s hardware was a challenge, so was programming its software. Though the F-8 shipped with an assembler (a program that translates low-level assembly language into machine-readable binary code), it had no native assembly ability. Instead, code had to be written on a GE time-sharing system then uploaded to a central mainframe, where it was compiled into binary and sent back – a process so time-consuming that the developers were sometimes able to get only two “turnarounds” a day. (Olsen 2015)

After a laborious effort, Mirco was able to get PT-109 ready for the 1975 MOA show, where it drew a good deal of attention owing to its use of a microprocessor. Ultimately, however, despite its innovations, the game sold poorly. Though this may have been due to technical issues, another potential problem was that PT-109 was only available in cocktail table format. By the time it appeared, the cocktail video boom had passed and the same doctors and lawyers who had purchased TV Ping Pong and Challenge were unwilling to buy another video game. As a result, PT-109 is all but unknown today, and even the most ardent video game collector is probably unaware that it had a microprocessor, much less that it was one of the first video games to use one.

The above article on PT-109 appeared in the  March 5, 1976 issue of EDN

So which was first, PT-109 or Gunfight? Both were introduced at the 1975 MOA show (for some other contenders at the same show, see my earlier post) but I am not sure exactly when they began shipping to distributors. The release of both games was announced in the trade magazines in November but I don’t know which came first. Whether or not PT-109 was first on the market, its sales were dwarfed by those of Gun Fight. As far as priority goes, let’s call it a tie for now.

What about other coin-op games?

I am not sure what the first coin-op game to use a microprocessor was. The first one I know of was Bally’s Bally Alley, a wall-mounted bowling game released in 1974 that used an Intel 4004. I have not done nearly enough research, however, to state with any certainty that it was the first.

As for pinball, a number of companies had experimented with microprocessor pinball games in 1973 and 1974, including Atari, Ramtek, Bally, and Allied Leisure. I am not sure which was first, but my guess is that it was Atari, which produced a prototype game based on Bally’s Delta Queen at its Grass Valley skunk works (when Williams and Bally later went to court over Bally’s microprocessor pinball patents, engineers from Grass Valley testified as friends of the court and Bally’s patents were ruled invalid).

It’s a bit ironic that PT-109 is so little known since the one Mirco game that anyone does remember is the pinball game Spirit of ’76, which is generally considered the first production pinball game with a microprocessor, despite that fact that it may not have been.

Spirit of ‘76

The initial idea for Spirit of ’76 had come from Dave Nutting, who had approached Mirco after Bally passed on the Intel-4004-based Flicker prototype he and Jeff Frederiksen had developed in 1974.

[Dave Nutting] When I did the first microprocessor pinball game, Bally at first didn’t want to pay the price I wanted for the patent so then I went to Mirco and had a contract with them and we came out in 1975 with a game called Spirit of ‘76. (2001)

The use of a microprocessor (in this case, the Motorola 6800) offered a number of advantages over electromechanical pinball games. One the biggest was that it allowed machine to track each player’s game state so that they could pick up from where they left off. It also allowed for the creation of more sophisticated sound effects, such as drums, whistles, and cannon fire, along with providing automated diagnostic routines and a host of operator-adjustable settings. Like PT-109, Spirit of ’76 caused a buzz at the MOA show and the games also drew the attention of the press – at least the electronics press – with articles appearing in Electronics, EDN, and Electronic Design. Mirco, however, was ultimately unable to capitalize on the publicity.

[Cash Olsen] Interest was very strong and we were riding on a big bubble after the show. Apparently, large orders were written and unrealistic delivery dates promised. We went back to Phoenix with a great deal of pressure because both games were still in prototype status; nothing was finalized and ready to turn over to manufacturing. The next several weeks were spent readying a couple of more prototypes of each game for delivery to the first customer; I believe it was [C.A.] Robinson in California. The [sales] price that …[Mirco] committed to was well below the cost of manufacturing the games as they currently existed…the silkscreens of the glass and …[playfield] of the pinball machine were of particular concern. Sourcing of the plastic and electro-mechanical parts of the play field was not firm and Bally/Midway seemed to control most of them. As shown at MOA, they used seven screens, …[which] caused the cost to be excessive, (2015)

Spirit of ’76 also suffered from technical problems. After shipping the first units in November, Mirco had to halt production until March as they worked out the issues (Walker 1976).

[Cash Olsen] I think that 2-3 months had gone by and the customer was making threats of cancellation and maybe worse. After days of all-nighters two pinball machines and one video game were readied and loaded onto a Cessna 205 to be flown to California to meet the deadline. When the pinball machines were setup on location we got a panicked call back that the machines had both played for less than two days before they could not be played anymore. The report was that all of the solenoids were hanging by their wires. (2015)

So though Mirco may have led the microprocessor revolution, it did not reap its rewards. Spirit of ’76 reportedly sold an abysmal 140 units and it remained for Bally/Midway to popularize the concept of microprocessor pinball machines and video games. Even if Mirco had been able to meet the initial demand, it may not have mattered. Technical issues aside, Spirit of ’76 was an ugly game. The dull-as-dishwater backglass consisted of little more than a stylized American flag and the playfield art was virtually nonexistent, possibly because no one at Mirco had any experience with pinball games

[Cash Olsen] Mirco knew absolutely zero about dong a pinball machine when they started Spirit of 76…they could have hired the janitor at Bally and he could have bought more corporate knowledge about pinball…than…all of the people involved at Mirco. (2015)

Like Olsen, Spirit of ‘76’s designers had come from Motorola, where they had worked as applications engineers on the 6800 microprocessor family. Neither of them had ever designed a pinball game before. Not surprisingly, Mirco made just one other pinball game – the 1978 cocktail pin Lucky Draw.

So was Spirit of ’76 the first microprocessor-based pinball game? As with Gun Fight it was introduced at the 1975 MOA show and as with Gun Fight, there were other games released at the same show that apparently also used a microprocessor.

One, Allied Leisure’s Dyn-O-Mite - which featured the likeness of Jimmie Walker from Good Times – is fairly well known. The other, Invasion Stratogy from Komputer Dynamics, is not.

Based in Indianapolis with a production plan in nearby Spencer, IN, Komputer Dynamics was organized in 1974 by Richard Payne, Chad Zulich, Ronald Young, and Charles Russell (whose father Louis was at the time the longest surviving heart transplant recipient). Invasion Stratogy (no, that’s not a misprint) was a two-ended pinball game in which two players could play head-to-head (a concept that had been tried in 1971 with Gottlieb’s Challenger). Two balls were in play at the same time and each player had four flippers. The game does not appear to have done any better than Challenger, which sold just 110 units, and Komputer Dynamics quickly disappeared.

So should these three games be considered co-holders of the “first microprocessor pinball game” title. Maybe not. As it turns out, Allied Leisure also produced a four-player version of Dyn-O-Mite called Rock On, which may have been released in September – though this too appears to be uncertain.


  1. Any recommendation on who would be a good choice to takethe cocktail pinball Lucky Draw by Mirco in for repair?

    1. I forgot to mention I’m in California and recently acquired Lucky Draw by Mirco. it lights up but does not seem to function. I’m not sure if it will be a major or minor issue but was wondering who in CA might be a good choice for expertise on this type of machine.