If you have been following our content for a while, you’re probably somewhat familiar with the JAMMA standard. Basically, it’s a wiring standard that was created by arcade manufacturers in order to make swapping game boards into cabinets an easier task. We’ve recently seen a rise in boards that use what’s being referred to as the CHAMMA (or Chinese JAMMA) standard. While the two are similar, there are some notable differences that you should be aware of. In this post, we will discuss the CHAMMA standard and what makes it different from the JAMMA standard.
The CHAMMA standard is a wiring standard that shares a lot in common with the JAMMA standard. Both use the same size harness and the same number of pins (28 pins on both the parts and solder sides of the board). The CHAMMA standard also features the same key in the pin 7 position. So, if the size of the harness, number of pins, and key position are the same, what makes CHAMMA any different from JAMMA? Well, it comes down to the wiring of the pins.
Before we move on, we would recommend that you check out our post entitled Buying A New JAMMA Harness? This One Is The BEST! if you are looking to buy a CHAMMA or JAMMA wiring harness. As we mentioned above, the two harnesses are indistinguishable from each other except for their wiring schemes. This means that a standard JAMMA harness will work for either a CHAMMA or a JAMMA setup. With that said, not all JAMMA harnesses are the same. Save yourself some time and trouble and get a good one.
The original version of the JAMMA standard only had support for three action buttons per player. Many fighting games (such as Street Fighter, Mortal Kombat, Tekken, etc.) got around this limitation by using a kick (or additional) harness that hooks up to a separate connector on the board and allows for the addition of more buttons. While this was a good workaround, it did take away some of the convenience of the JAMMA standard as additional wiring changes needed to be made any time you swapped a board into a cabinet that used more than the three action button slots that were available on the harness.
Another workaround to the “three action button problem” of the original JAMMA standard was to use the additional pins near the end of the harness for the extra action buttons for each player. Companies like SNK were the first to start adding action buttons to these pin positions. While that worked great for SNK (whose games typically use 4 action buttons), it was not enough to accommodate the Street Fighter II six button style since there were only enough pins for five total action buttons. The JAMMA standard features ground wire positions in the last two pins of the harness the first of which would block you from adding an additional sixth action button.
In order to get around this limitation, some manufacturers started using this first ground position at the end of the JAMMA harness (or the pin 27 position) as the sixth action button position and that’s pretty much how the CHAMMA standard was created. The CHAMMA standard has greatly grown in popularity recently due to the rise of multigame boards such as the Game Elf series, Pandora’s Box series, and various other Chinese multi-fighter boards. It’s easy to see why the companies that manufacture these boards decided to go with the CHAMMA standard over JAMMA. The CHAMMA standard saves them from having to include an additional header on the board and harness for the extra buttons. It also helps that converting a JAMMA cabinet to CHAMMA is a relatively simple procedure.
Converting a JAMMA wired cabinet to CHAMMA is really just a two-step process. First, cut the ground wires that are going to pin 27 and connect them to pin 28 (or another ground pin on the harness) with the existing wires. Second, wire your sixth action button to the pin 27 location previously used by the relocated ground wire. When you cut the ground wires at pin 27, you may want to leave a bit of wire there to connect your sixth action button for each player. Of course, you can always just crimp a new pin on to the sixth action button wires and insert them into the harness directly. The choice is yours.
There are also adapters available that will convert JAMMA wired cabinets that have specific kick harnesses installed to the CHAMMA standard without having to modify the wiring. For example, MikesArcade.com has a Game Elf/Pandora’s Box/CHAMMA to JAMMA adapter for cabinets that currently have a JAMMA harness with a CPS-1 kick harness installed. The adapter will also work with a CPS-2 kick harness provided that you use their CPS-2 to CPS-1 Kick Harness Adapter.
Buy the CHAMMA to JAMMA adapter from MikesArcade.com now!
Buy the CPS-2 to CPS-1 Kick Harness Adapter from MikesArcade.com now!
We have printable versions of the both the JAMMA pinouts and CHAMMA pinouts for your convenience. These pinouts will come in very handy if you need to use either of these standards in the future. Please click the links below to access the documents.
JAMMA pinout sheet – http://www.arcaderepairtips.com/jamma.html
CHAMMA pinout sheet – http://www.arcaderepairtips.com/chamma.html
With multigame boards such as the Game Elf series, Pandora’s Box series, and various other Chinese multi-fighter boards becoming more and more favored among arcade enthusiasts, it is safe to say that the CHAMMA standard is here to stay. Familiarizing yourself with the difference between the CHAMMA and JAMMA standards will help you when trying to make that wiring conversion between the two types in the future. Please leave any questions or suggestion in our comments section below.