Exidy 440 Dev Kit on Cheyenne

On Saturday I spent much of the afternoon installing the Exidy 440 Dev Kit that adds another 9 games to an existing game board, so basically all the Exidy shooting gallery games can be played on my Cheyenne cabinet, such as Crossbow, Combat, Chiller, Clay Pigeon, Catch-22, Crackshot, Hit ‘n Miss, Combat, WhoDunit, and Showdown.
That is pretty awesome, and as. with the Millipede multi-game installation, this one went pretty smoothly, although quite time consuming given the total number of chips I needed to remove was over 50!

I documented the process fairly heavily and uploaded the photos to Flickr as an album because I want to remember everything I did should I ever need to revert the board back to a stand alone Cheyenne. This is the second of four multi-game mod kits I’ve installed, the other two are for Gyruss (happening later this week) and Pac-man, which will have to wait until next year given that game is still in Virginia—in fact there are quite a few that need to make the jump over the pond 🙂

That’s a cool wall! pic.twitter.com/47r3XFoXTr

— Jim Groom (@jimgroom) November 9, 2021

I will spare you a play-by-play here of this project given HighScoreSaves has documented it well in their Exidy 440 Dev Kit Installation Guide. That said, the project reinforced a few things:

• The value of taking a lot of pictures of edge connectors and chip placement given I was continually come back to what chip was placed how when adding the daughter cards.
• How awesome socketed chips are because the do not require any soldering—learned this lesson the hard way with desoldering the Phoenix CPU.
• Patience is always a virtue when removing chips, and I spent well over an hour listening to music and slowly and methodically removing dozens of them
• Preserve anything removed given originals are always valuable—a saved all the EPROM chips I removed and organized them accordingly so I can replace them if need be

I also think the game board in Cheyenne is a Crossbow board, at least the date 1983 suggests as much, and I imagine Crossbow was the earliest of this group and then the various variations were just modifications. But I have heard that swapping boards between these Exidy games can create serious issues with the power supply, which concerned me after buying a Crossbow back-up board for this game. But now I know it is a Crossbow board I think I might be in good stead.

Above is the orginal board before removing EPROMS and chips and adding daughter boards, and here is the Crossbow label on the sound board:

That 1983 copyright makes me think it is a Crossbow board with Cheyenne chips given Cheyenne was not released until 1984. The main board also has a date of 1983, but I’ll have to do a bit more digging to confirm this.

Above is a look at the main game board will all EPROMs removed and the daughter card inserted in the 6809 CPU as well as the PROMs K7 and H9.

And the picture above has a visual of both the main board as well as the sound boord installed above it with the two daughter boards over the EPROMs and the 6809 CPU with a ribbon cable connecting the two.

I did run into one issue on the first attempt at installing the board, the ROMs read cleanly but never booted beyond a check. Turns out I did not turn off the dip switches on the main board, but after doing that it loaded cleanly to the boot-up menu and allowed me to change cabinet, high score save kit, and game settings. You can pretty much do everything from that menu, include adjusting sound, deciding which game you want to be the default at boot-up, custom sound settings (stereo versus mono), turn on/off attract sounds, save all high scores, and much more. I really love the culture around modding these old 1980s video games to both keep the original experience while at the same time providing you a bit more convenience along with a few more games to play. It is a perfect balance between the absolute purism of all original serial numbers and the undignified generic LCD cabinet with MAME games galore.

And I now get to play my favorite of the Exidy shooting gallery games: Crossbow!

Projects like this that keep on giving after they’re finished really do make this hobby quite rewarding!