First, here is a bit of history behind the meaning of the acronym, JAMMA.
In the dark ages of the Golden Age of arcade video games (1984 and earlier), game makers operated in small exclusive domains where they designed game components in a way that best served their own interests.
Consequently, each had its own proprietary circuit boards, power supplies, and wiring harnesses. Basically, there was no component interchangeability between a game cabinet from one manufacturer and a game cabinet made by someone else.
Thanks to the Japanese, around 1985, all that exclusivity was deeply buried. The Japan Amusement Machinery Manufacturers Association (JAMMA) created some industry standards, in particular for the design of game printed circuit boards (PCBs). And things changed forever.
The most important and influential of these new standards was the standard PCB pinout. Any gaming PCB that meets that pin assignment standard is what we now call a JAMMA board. You can see the JAMMA logo stamped near the pinout section of a JAMMA board. Almost all JAMMA boards sport this logo.
The wiring that connects the game components: monitor, power supply, control panel, speaker, etc. – the PCB is called a JAMMA harness. The 56-pin edge connector of the wiring harness sits on the pin fingers of the PCB.
There are many JAMMA terms that we have come to hear and use frequently: JAMMA board, JAMMA harness, JAMMA edge connector, JAMMA cabinet, etc. At the root of its meaning is nothing more than the concept of PCB interchangeability between cabinets different manufacturers.
And it’s JAMMA’s standard PCB pinout (shown below) that has made this possible.
The following JAMMA pinout chart is basically a map of the 56-pin edge connector of the JAMMA wiring harness. When properly seated on the PCB, the edge connector connectors will line up with your fingers on the PCB and your set will work.
When you get tired of a game, you can plug in and play the JAMMA PCB for your next favorite game. Plug-and-play simply means unplugging the edge connector from one PCB and plugging it into another PCB.
And that plug-and-play process can go on over and over again, because there are now thousands of JAMMA game PCBs that you can play in your JAMMA cabinet. Thanks, Japan.
JAMMA PINOUT TABLE
Solder Side – Alpha Characters – 28 Pins – AZ, af
The solder side is the bottom side of the PCB. It is the side where the welded connections of the parts are exposed. Few parts, if any, are located on the weld side. The solder side pinout is identified by alphabetic characters.
Parts Side – Numeric Characters – 28 Pins – 1-28
The parts side is the top side of the PCB. It is the side where the pieces are located. The pinout on the side of the pieces is identified by numeric characters.
Usually the PCB is printed and the edge connector is engraved with the alphanumeric characters.
EARTH – A, 1
EARTH – B, 2
+ 5VDC – C, 3
+ 5VDC – D, 4
-5VDC – E, 5
+ 12VDC – F, 6
KEY SLOT – H, 7
COIN COUNTER # 2 – J
COIN COUNTER # 1 – 8
LOCKING COIL # 2 – K
LOCK COIL # 1 – 9
SPEAKER (-) – L
SPEAKER (+) – 10
N / C – M
N / A – 11
GREEN VIDEO – N
RED VIDEO – 12
VIDEO SYNCHRONIZATION – P
BLUE VIDEO – 13
SERVICE SWITCH – R
VIDEO GROUND – 14
TILT SWITCH (SLAM) – S
SWITCH TEST – 15
CORNER SWITCH # 2 – T
CORNER SWITCH # 1-16
PLAYER 2 – HOME – U
PLAYER 1 – START – 17
PLAYER 2 – UP – V
PLAYER 1 – UP – 18
PLAYER 2 – DOWN – W
PLAYER 1 – DOWN – 19
PLAYER 2 – LEFT – X
PLAYER 1 – LEFT – 20
PLAYER 2 – RIGHT – Y
PLAYER 1 – RIGHT – 21
PLAYER 2 – BUTTON 1 – Z
PLAYER 1 – BUTTON 1 – 22
PLAYER 2 – BUTTON 2 – a
PLAYER 1 – BUTTON 2 – 23
PLAYER 2 – BUTTON 3 – b
PLAYER 1 – BUTTON 3 – 24
N / C – c
N / A – 25
N / C – d
N / A – 26
EARTH – e
EARTH – 27
EARTH – 28
Understanding the JAMMA pin board:
N / C – Without connection.
Key slot – A keyed slot that aligns with an omission in the PCB pinout section.
This safety feature is provided to ensure that the power section sits at the correct end of the pinout section. If the edge connector is reversed and the power section is seated on the wrong or opposite end, irreparable damage to the PCB can occur.
If the key has been removed from the edge connector, mark the connector as “parts side” to help ensure proper seating.
Power section – Pins AF, 1-6, e, f, 27, 28
Video section – Pins N, P, 13-15
Corner section – Pins J, K, T, 8, 9, 16
Controller section (joystick) – Pins VY, 18-21
Button switch section – ZB pins, 22-24