bavacade Update 1-19-2025

This week was pretty productive on the bavacade front by making real headway on the plan to start cleaning up the small things. I knocked out quite a few things on the list prepared in the last update:

  • Switch Robotron 1P and 2P button
  • Fix Millipede’s extra Matsushita chassis
  • Took apart Pole Position and add wheels
  • Investigate issues with either power board or inline power brick for Stargate
  • Test non-working Super Cobra board with game roms from working board
  • Check chassis power plugs and clean-up any electrical tape monstrosities (ongoing, but partial progress)
  • Try 440 Exidy kit on non-working Crossbow board for Cheyenne (in-process, waiting on daughter card from America)
  • Take apart Cheyenne and add wheels
  • Fix Make Trax yoke connector
  • Check and clean-up wiring for Venture
  • Fix back-up Hanterex 20″ Polo chassis
  • Fix K4600 back-up interface and main chassis boards
  • Fix wheels on Dig Dug and Bagman

Robotron

Robotron Player 1 and 2 Button Switch

The swapping of the Robotron player one and two buttons was quite easy. I just had to unscrew and swap the housing for the contact strips. Nothing’s better than a simple fix.

Robotron Player 1 and 2 Button Swap

Player 1 and 2 button assembly for Robotron

Millipede

Testing the back-up Matsushita chassis for Millipede was a little more involved. I swapped out the original chassis given it was playing blind and I had easy access to a new, working chassis. That said, while installing the new one I realized that the pots for brightness and screen on the original chassis might need to be re-soldered. I promised to return to it, but given the new chassis was working great it fell to the bottom of the list.

Millipede Backup Matsushita Chassis has Washed out Red

Millipede back-up Matsushita chassis has washed out red

But I’m now chasing down all these lingering issues, so figured it was time to swap in the original chassis to see if I can get it working again, and I did. Turns out I was right about the brightness and screen pots, and a little reflowing of solder joints there got the chassis back-up and running. That said, the red on this chassis is definitely washed out compared to the new one, so may need to do some color adjustment should it be used in the future. For now it’s a good bet for a working back-up, which is always nice. The new chassis looks so good that I had to swap it back in. What’s more, I realized that the way to fix the high score going off screen at the top with the new chassis is to adjust the horizontal width coil. I ran out of time, but I will return to it this week and knock another small issue off the list.

Super Cobra

Super Cobra Main Board

Super Cobra main board with 6 game roms I had burned and added to no effect

I dug in on testing why one of my two Super Cobra boards was not working. Quick back story, I bought a Super Cobra board with a high score save kit that never worked right; there were so many glitches it was unusable. So I took the save kit out, but turns out the original graphics and game ROMs had been removed, so I needed to have a new set burned. When adding these new ROMs, the game was still throwing garbage to the screen—so nothing doing.

Super Cobra Main Board

Supper Cobra main board with the 6 original, working chips that will be copied

I was still convinced it was the game ROMs, so to test that theory I took the working 6 ROMs from the working board I have and added them to the non-working board and lo and behold it worked. So, the new plan is to have the 6 working ROMs copied to new chips, given the other copies might have been corrupted or just bad files, etc. I’m thinking 1-to-1 copies of the working chips should solve this issue, but we will see.

Stargate, Robotron, and Defender

Investigations into why Stargate restarts after a period of time continue. I’m not sure if it is solved, but it has led me to discover and clean-up other issues, so for that I’m thankful. The issue is Stargate runs fine with the original power board and brick for several hours, but then out of no where restarts. When the board is connected to the switching power supply this never happens, which leads me to believe it is an issue with original power board. The power bricks seldom have issues in these games, so I started by troubleshooting the power board. To do this I swapped out a board from another Williams game I have that are compatible (namely Joust or Robotron) with Stargate.* I went to Robotron to get its power board when I discovered a pretty bad hack job that had wires individual soldered to the back of the board rather than using a connector. I sign of some shoddy workmanship:

Robotron Power Supply Board with Bad Soldering

Back of the power supply board in Robotron with wires directly soldered on the board, a big no no.

This is unacceptable. I removed the board and gave it to Roberto to work on, along with the Super Cobra chips. It was obvious the power board burned up at some point, and rather than addressing the issue they just worked around it for the pieces they needed. Not bavacade, Roberto will get to the source of the issue and give this power board a new lease on life.

Robotron Power Supply Unit Issues

Top of Robotron power board where you can see signs of burned connections

With the Robotron power board unusable, I grabbed the Joust board which was in much better shape.

Joust PSU Board

The Joust power board is like new comparatively.

So back to Stargate, the idea was to take the power board out of Stargate and put it in Joust and vice versa. This way if Joust restarts after several hours I’ll know it was the power board, and if Stargate restarts I’ll know it was the power brick. Well, after many hours of keeping them both on neither restarted. So it’s inconclusive, yet with each game working cleanly without restarting we arguably have a temporary fix, right? Maybe, but if experience is any lesson these things always re-emerge. Nonetheless, for the moment I’ll let it ride.

Robotron power board with wires soldered right to back of board, pretty freaking ugly

The work that will be done on the Robotron power board counts toward the broader goal of going through each game and looking for any wiring issues, and I think this will prove one of the worst offenders.

Defender Power Supply Board

Defender power supply board

On the topic of Williams power boards, while looking for potential power boards to swap I realized another issue I never dealt with was a problem with the Defender power board (very different from that of Stargate, Joust, and Robotron, even though a Williams game). When I was refurbishing Defender I came across an odd ROM error that I ultimately fixed by swapping out the old power board for a back-up I had (there are a lot of back-ups in bavacade 🙂 ). Finding the Defender power board I’d noted masking tape with +5V written on it, so figured there was an issue with the +5V? That’s what happens when the metadata is sparse. I re-tried it and this time it worked without any problems. More gremlins, for sure, but it’s also another back-up part I can mark as working until it inevitably doesn’t.

Pole Position

Pole Position

As a way of coping with the stress of a large, complex migration at Reclaim Hosting this weekend, I disassembled Pole Position. This was a long time coming, it’s one of the last games to get on wheels before relocating to bava.studio. I created an album of images for reference when it’s time to reassemble after fixing a few structural issues and getting it mobile. I’m gonna see if Alberto can document a bit of his process when adding the wheels given: a) it would be good to know, and b) Tim is looking to get some of the cabinets at Reclaim Arcade on wheels—which would be a huge win and put his word working skills to the test 🙂

Cheyenne

Finally, I have the missing daughter board for the 440 Exidy multi-game kit being shipped to me after a year of chasing that down. A chip on that kit went bad (this is why proprietary chips suck), and as a result the 440 kit was useless. I already have two Cheyenne boards, but one of them stopped working. Before I embark on a repair, however, I want to see if adding the 440 kit brings it back to life. We will see….

_______________________________

*They all use the Revision B power board in my case.

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3 Responses to bavacade Update 1-19-2025

  1. Eric Likness says:

    Blog or Die. Narrate the Work. (And Snake Plisken’s camera skills documenting the existing condition of Pole Position, ). A dual purpose, a full BEFORE series, but also the semi-schematic for re-assembly when the time comes.

    Do not stop now! Keep on Bloggin’ (insert Keep on Truckin’ t-shirt graphic here)

    • Reverend says:

      I like that you are the only one that appreciates these posts! Keep the comments coming, and the bavacade will live on. Without you all these games would be in the. dump 🙂

  2. Eric Likness says:

    And the thought of those circuit boards, those decorated particle board cases, those CRT’s buried under tons of e-waste, or (worse) unsorted trash, water bottles, Pampers, IKEA boxes, McDonalds bags,… would break my heart. These are the Saturn V rockets, Supermarine Spitfires, the B29 Superfortresses, the Ford Model T, the Conestoga Wagon what built the West. WITHOUT these, there would be no now. Not the way is now.

    Let’s celebrate those giants and consider those shoulders upon which we trod.

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