Bait & Switch

The Atari Roadblasters I picked up is in good overall condition, and the major parts are working, but most of the controls have problems of one sort or another. The steering yoke was half disassembled when I picked the machine up, with a pile of parts rattling around in the coin box. A few of the trigger and thumb button switches had been replaced, with incorrect parts, and one of the actuator buttons and several screws were gone altogether.

I brokered a deal with another local collector and got my hands on a second mostly complete yoke and pedal assembly… I still needed the right switches though…

I knew I recognized the switches from somewhere… That somewhere turned out to be the mechanical switch keyboards all the nerds are going crazy for nowadays (self included). I happened to have such a thing lying around, one of the cheaper and more commonplace of its kind, a Dell AT101W.

This model comes populated with Alps black keyswitches of the non-clicky variety. The one I had was also fucking filthy. As a rule, if you haven’t personally cleaned a keyboard in the last year or so (and I mean really, complete disassembly involved, cleaned it) it probably looks like this inside. Thought you all might appreciate that knowledge…

The other side of that mess is a PCB like this, to which each of those keyswitches is soldered.

Some quality time with my desoldering pump later, I was able to peel the PCB away from the keyswitches and their mounting plate. If you desolder the connections well, they’ll come apart much like this. If you do it wrong, you’ll either get nowhere, or rip the guts out of all of the keyswitches. Don’t try to do this with wick or a manual pump, is all I can say.

Even exercising some care I ended up breaking a pin or two on several keyswitches. Seems like they’re fairly brittle. Even with some loss I still ended up with plenty for this project though.

Removing the switches from the mounting plate was tedious but straightforward. Each switch has four tabs that secure it to the plate. I used a steel ruler to push in one side of two tabs at a time. It took a while but I was able to remove all of the switches without damage.

Alright, this is what really matters… On the left is one of the Omron B3G-S keyswitches that came out of the yokes originally. On the right is one of the black Alps from the Dell keyboard. Below is the small PCB the switches mount too and ride on inside the yoke assembly.

We can see a few differences right off. For one, the Omron switches have three pins, while the Alps have only two. The extra pin on the Omrons doesn’t matter, it only comes into play if you want to use these switches in a normally closed configuration, which is not the case for the Atari yoke. The small PCB the switches will be installed on is set up for a variety of different pinouts, so the slight difference in alignment doesn’t matter either.

There are two differences that *do* matter though…

First, the Alps switches have slightly larger pins than the Omron ones. This was easy to handle by enlarging the holes on the PCB with an appropriately sized drill bit in a pin vise.

Second, the Alps switches have a different setup for mounting then the Omron switches, and the yoke body halves assume you’re using the Omron type. To get the Alps to fit I had to clip off the tabs, and file down the remaining plastic to match the profile of the Omron switches while retaining the rectangular protrusion that keeps the switches from being pushed down into the yoke assembly.

The above picture shows an Omron switch on the left, a modified Alps in the middle, and an unmodified Alps on the right. A small straight file is sufficient to mod the Alps switches to fit, they should end up around 14mm wide when all is said and done.

Here we can see one of the original Omron switches installed in the lower position with the white actuator pin, and a modified Alps switched installed in the upper position with a black actuator pin.

It’s a bit of work, but considering the high failure rate of the Omron switches, and the fact that used replacements start at six bucks each and only get higher from there, I found it to be worth the effort. A single mechanical switch keyboard should have me covered for several lifetimes as far as replacement switches for this style of yoke go, and I know this style of standard key switch is used in other games as well.

If you’re another Roadblasters owner coming upon this information be advised that this is only confirmed for the kit style Roadblasters yoke. The dedicated Roadblasters yoke is a different assembly entirely and may use different switches. If anyone has pictures of the internals of a dedicated style yoke, or information on the switches used therein, please send them to me and I’ll update the post to include that information.


Zenith Avanti console television with Space Command ultrasonic remote, Gemini Colorgem VHF/UHF rabbit ears antenna, Atari Pong console. May not get the channels you want, but has all the woodgrain you can handle.

I got the TV gratis from a guy doing some spring cleaning in a super rad dome house out in SW Portland. I think it was probably a period fixture from around when the place was built, along with the the electric blue shag carpet in the room it came out of. Was almost sad to be taking it out of its natural habitat.

Flying High Again

Back in September of last year I picked up this Atari System 1 cabinet from a guy down in Salem.

Originally an Indiana Jones, at some point it received a Hydra conversion kit. The two axis flight yoke controller installed for that is similar to the one used in several other Atari games, Star Wars most famously. It uses a 5k potentiometer for each axis, and has a trigger and button in each hand grip, which makes it one of the more versatile yoke style controllers (others lack the second axis or the thumb buttons). The Hydra kit also added a foot pedal with another 5k pot which adds to the games the cabinet can potentially support.

I decided I’d like to wire it up so it could easily be swapped between different games using the Hydra yoke and pedal. I started out with installing a new unhacked JAMMA wiring harness, and running the wiring for player 1 and 2, and the pedal, straight up to the control panel area.

Then I built some adapters I could place in line between the control panel and pedal wiring and the JAMMA harness to adjust the pinout for different games.

I struggled with the wiring for the potentiometers initially. Not having worked with them before I didn’t realize that they need to have power run across them and then have a reading taken from the wiper. I tried wiring them up with just wiper and ground pins and was stymied for an embarrassingly long time by the odd values I was getting trying to calibrate the controls.

Once I ran a 5V feed up to the control panel and modified my adapters to accommodate power I got things working as expected. Then I turned my attention to the yoke controller itself. It’s definitely seen some hard use and questionable maintenance. I reworked the wiring inside the yoke and fixed the shameful soldering quickly enough.

The bad part was this bodge job. At some point the original screws holding the left handgrip in place were broken or lost, and replaced with square drive carpentry screws, one of which itself ended up breaking off. Messed around with that situation for too damn long, in the end I couldn’t remove the broken screw and just drilled out enough of it to allow the handgrip to come off.

Unsurprisingly, wood screws left the assembly with considerable play allowing the parts to abrade horribly.

I put it back together as best I could and greased the bushings and springs. The hex head screw isn’t exactly what belongs there but at least the threading and length are right. Good enough for now. I need to take the whole thing apart more thoroughly later on to rewire the left handgrip buttons and replace the broken centering spring. That was a little bit more project than I cared to bite off at the moment though since none of the remaining flaws impede gameplay.

Did some testing with the new adapter for Hydra, all looks good…

…then with Road Riot 4wd which runs on very similar hardware.

Success! That takes care of the major to do item for this cabinet. I still need to fabricate a new front door for the compartment with the power supply and PCB, and perform the rest of the yoke repairs. After that I want to build another adapter for the Vapor TRX board I have, and set up that PCB with a flash drive replacement for the failing Quantum Fireball hard drive it came with.