Updated: 2/24/2002 MultiJAMMA FAQ/README 1.2

MultiJAMMA Important Information:
  • Experience: The MultiJAMMA requires a moderate level of understanding in hooking up power supplies and JAMMA type game boards. Please DO NOT purchase the kit if you are uncomfortable doing something like wiring up power to a game cabinet. If you do things wrong you can destroy the MultiJAMMA and the game boards attached to it. If in doubt, hire a local video game electronics technician. I will only be able to give "generic" suggestions-- I will not help with your particular installation. It's too easy to misunderstand things in e-mail!
  • AS-IS: Due to the "do-it-yourself" nature of the kit and the dangers of hooking up the power wrong, the MultiJAMMA is sold AS-IS with NO RETURNS OR REFUNDS. Each kit is fully tested before shipment. If any MultiJAMMA component fails I will be happy to repair or replace it, but you will be responsible for parts and labor charges.
  • Monitor Type: The MultiJAMMA will work best with an "auto-sync" type game monitor. (In general this is most any monitor made after about 1994 or so, and most any that came in a factory-built "JAMMA cabinet", but there are other ones as well.) It is possible to use the MultiJAMMA on an older manual-sync monitor, but depending on your game boards the display on some games could "roll" or not sync without manually tweaking the monitor controls when you switch games.

To test your monitor you can do the following:

  1. Collect the game boards you would like to use with the MultiJAMMA.
  2. One at a time, plug in each game board and turn on your game. Make sure the picture looks "normal" without having to make any adjustments on the monitor.

If the monitor did not sync on one or more of the games, or if you had to manually tweak the monitor to get it to sync (I warned you not to!), the MultiJAMMA will act the same way. (So if one of the games "rolls" on the monitor without the MultiJAMMA, it will do the same through the MultiJAMMA too!)

You may be able to set an older manual-sync monitor to a setting that will sync for all the games through trial and error. It will depend on the monitor and the games however.


  • Power Supply Part 1: You will need to add an additional power supply (or two) to your game cabinet to supply power for the game boards. The power supply is not included in the price of the MultiJAMMA. The MultiJAMMA will use the power supply in your JAMMA cabinet for its own power, but additional power is needed for game boards connected to the MultiJAMMA. The switching power supplies used in personal computers are recommended for use with the MultiJAMMA.
  • Power Supply Part 2: Power requirements for the additional power supply(s) will vary with your games, but in general you can use the following guideline:
  1. Assume 5 Amps of +5 Volt power for every game board.
  2. Assume 1 Amp of +12 Volt power for every game board.
  3. Some -5V current (for some games only).

When in doubt, go with bigger power supplies.
Following this example, a full 8-game MultiJAMMA would require:

8 * 5 Amps = 40 Amps of +5 Volt power

8 * 1 Amps = 8 Amps of +12 Volt power

Some -5V supply

Since most "PC" power supplies are rated for about 20A of +5 Volt power, a "safe" configuration would be two PC power supplies-- one for every four games. (The 5 Amp per game "rule of thumb" already has safety margin calculated in, so being right at the rated limit of the power supply is OK since the rating should be "overkill" already.)

Users with electronics experience can measure the current being drawn by their games and select a power supply more specifically suited for their application if so desired.

Remember-- if in doubt, just buy a power supply that you know is larger than you need.

  • Cables: The MultiJAMMA includes the cables to connect to the game boards. The MultiJAMMA switchboards include connectors that plug into PC-style disk-drive power connectors-- those will be adequate for most games. If your game board is particularly power-hungry, or if it requires -5V power (usually for Audio output) there is a high-power 8-pin .156" header connector that you can cable your power supply to. You will need to make (or buy from someone else) any power supply cable that goes to the 8-pin header.
  • Screen orientation: The MultiJAMMA doesn't do any sort of screen-flipping or rotating. Most JAMMA games have a dip-switch setting to "flip" the screen, but not all do. Lots of older "classic" era games do not allow the screen to be flipped without flipping the monitor. Take this into account when selecting your games. The MultiJAMMA will not make a "vertical" game play on a "horizontal" monitor. (Other than by turning your head sideways...)

Frequently Asked Questions:

Q: How do I use the MultiJAMMA with fighting games (etc.) that have extra buttons?

A: The MultiJAMMA supports the three "standard" buttons for each player on the JAMMA connector. It also support the fourth semi-standard button on the JAMMA connector. To use the MultiJAMMA with fighting games you simply connect the extra buttons on the control panel directly to the extra buttons inputs on each game board. The buttons do not need to go through the MultiJAMMA at all.

Q. Will the MultiJAMMA work with JAMMA based driving games or paddle-type or gun games?

A. Similar to the question above, if the controllers used are non-standard the MultiJAMMA won't know what to do with them. On the other hand, the control signals don't have to go through the MultiJAMMA, so as long as the controls are compatible with the games you want to use, you can generally hook them together in parallel without any problems. (Gun games might have problems if there are too many games on one gun, you'll have to experiment.)

Q: How long have you had this available? Is it reliable?

A: The MultiJAMMA has been shipping since June of 2000. During that time I've only have two systems returned for repair. In both cases they were damaged by improper hook-up.

Q: How much is it?

A: The MultiJAMMA with two Switchboards is $125 + shipping/handling. Additional Switchboards are priced at $22.50 each.

Reseller/ System Integrator Information:

I welcome anyone that wants to resell or build systems using the MultiJAMMA to contact me. Due to the narrow margins on the product there will not be particularly deep volume price cuts, however by pre-building power cables and including power supplies into a complete solution for novice users there should be ample opportunity for good profit margins. In addition, for retail or eBay sellers multigame machines are a great way to improve the bottom line!


Updated: 2/24/2002

2002, Clayton Cowgill info@multigame.com