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Let's Make a Test Rig

Updated: Sep 13, 2021

There is a certain point in any hobby I guess when you need specific tools and/or devices to advance in the hobby. I will freely admit I was probably way beyond needing to build a test rig of some kind before I finally broke down and did it over the winter break. Having a test bench (or rig) allows you to easily test game boards, controllers, and monitors without having to dig into working games or drag things all over the place. It's also a bit safer... plugging in a partially working whatever into a known working game can be a bit of a disaster waiting to happen. Having a test rig means never having to say you're sorry.... well maybe not, but let's take a look at how I built mine.

For the last few months I have been doing a lot of monitor repair. And while working on the restoration of my Simpsons I realized what a huge pain in the neck it was to drag this huge 25 inch monitor around to other games while I was in the process of working on it. Boy I thought... a test rig would make this a lot easier. I've seen some rather fancy test rigs other collectors have (both handmade, and commercial ones) but I decided to keep mine pretty simple. I wanted a set on controllers, coin up buttons, voltage meters, and a JAMMA input. I essentially was building an JAMMA arcade game with no dedicated monitor in a small case.

To build your own super happy fun test rig you will need the following....

  • A switching power supply

  • An isolation transformer

  • A JAMMA harness

  • Some wire

  • A power cable

  • A speaker

  • A single fuse holder

  • Power block

  • Joysticks and Buttons

  • Tools

  • Some coffee, and some deep breaths

I like to keep my wiring neat and clean so I also recommend getting some quick connectors, wire tie downs, and a label maker if you want to be super fancy. I also recommend shrink wrapping your wires. It looks neater, and allows for a stronger... more professional looking connection.

You also need something to put all this stuff together in, and a control panel of some sort. I decided to make my life easier by using an old used control panel I had no use for anymore. The control panel was already populated with buttons and joysticks. Since it was previously used on a Nintendo style cabinet... I used the dimensions of the Nintendo control panel cabinet area to make the measurements for my test rig "box". I just added a bit more space in the back for the power supply and other goodies.

After some measuring and planning we started cutting out the pieces that would become the test rig case. My wife did most of the work at this juncture, since woodworking isn't really my forte. You could pretty much use anything to make the box for the rig if you wanted to I guess... wood is nice since it's cheap and somewhat easy to work with overall. Plus if you mess up a part you can always cut a new one before the final assembly.

At this point, the box was really starting to take shape. You can see our holes in the back of the box. These are for the power cord and JAMMA harness wires. I decided to add handles on the side to make it easier to move the test rig around when I wasn't using it .... or so I could take it wherever I needed to take it too. You never know where an arcade emergency might break out. Keep watching the skies.

Our first attempt to cut out speaker holes in the front panel proved to be terrible, so we decided to redesign the front a bit before final assembly and paint. (AKA... we redid the whole front panel from scratch because we hated it) I also found a better donor control panel, this old Nintendo VS. Control Panel was just perfect. Even the joysticks and buttons were still in great shape.

AHHHH second time is a charm. The new front panel turned out fantastic! Here we switched to a bit more artistic angled cut for the speaker grill, and added a rocker on/off switch to the front. Also we moved the voltage meter readouts to the front in a nice row. I used some generic silver spray paint for a bit of flair. Not exactly up to Bob Vila standards but pretty good in my opinion.

Once the case was assembled, I went ahead and built the power supply and connected the JAMMA harness. In the above photo you can see a fairly typical design for an arcade game power supply system including an isolation transformer. If you are not super familiar with doing this, there is a lot of great information here. Normally an arcade power supply would include power outputs for other things like a marquee light but I don't need those here. Now in a perfect world I would have a six bottom layout on my control panel for the JAMMA harness. Since almost every game I am interested in has two or fewer fire buttons... I decided not to worry about it.

On the side of the test rig I added two buttons for credits, and another for a test button. Again these were old buttons from some long ago restoration project. I love all this up cycling. I tend to keep a lot of parts from games I restore, but they never really get used. But this time.... it all paid off.

For the monitor inputs I made generic "plug and go wires" for the red, green, blue, ground, and SYNC so I could plug my rig into any normal CRT monitor I may want to test. I made the monitor power the standard quick connect that is seen in many CRT monitors. If this plug doesn't work for a particular monitor I can always use insulated alligator clips.

At start up you can see the voltage meters measuring +5, -5, and 12 volts from the power supply directly. This is extremely helpful since some PCB's are much more fuzzy about the over and under they can handle from the 5 volt line. Since I finished this project, the test rig has already proven itself to be a very valuable tool in the workshop. I have fixed two monitors and a PCB using the rig. I wish I had made the voltage pot on the switching power supply more accessible but I guess I can save that for the next design.

As a huge fan of the TV show Halt and Catch Fire (and as just a huge nerd overall) I had this badge made for the test rig as a tribute to the mighty Cardiff Giant Computer crew. What is the point of any hobby unless you can have fun with it right?

So there ya go.... when will you need to build a test rig of your own? It's hard to say. But having one of these would have made my life easier during any part of this crazy hobby that is for sure.

Happy Hunting!



UPDATE September 2021

After the requests for more information on the power system used on this project, I made this video which gives a step by step instruction on how to make a new power system for most arcade games.

3,501 views2 comments


Yes, Please publish the wiring diagram


Francis Paixao
Francis Paixao
Jun 20, 2021

Hello Cassie,

This is great but how did you hook up the voltage displays specifically?

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