Arcade Edge Connectors Explained: Dedicated PCB Connectors, JAMMA, and Adapters

By HighScoreSaves Technical Team

Reviewed and updated August 22, 2026

Many classic arcade PCBs connect to the cabinet through a row of exposed conductive contacts along the edge of the circuit board. The cabinet wiring harness mates with those contacts through an edge connector.

That connection can carry several of the signals required for the game to operate, including power, ground, video, audio, player controls, coin inputs, and other game-specific functions.

Although arcade edge connectors may look simple, they are not universally interchangeable. Dedicated pre-JAMMA boards, JAMMA PCBs, conversions, adapters, and reproduction hardware can use different pinouts even when connectors appear physically similar. Understanding that distinction is important before connecting, testing, or upgrading vintage arcade hardware.

What Is an Arcade PCB Edge Connector?

An arcade PCB edge connector is an electrical interface formed by conductive contacts—often called fingers—along an edge of the circuit board.

A mating harness connector slides over the PCB edge. Internal contacts inside the harness connector press against the appropriate board fingers, creating electrical connections between the arcade PCB and cabinet wiring.

Depending on the hardware design, these connections can include:

• Ground
• DC power such as +5V and +12V where required
• Video signals
• Audio signals
• Player controls
• Start buttons
• Coin inputs
• Service or test functions
• Other game-specific signals

The exact assignment of every contact is called the pinout.

Physical Connector Size Does Not Determine the Pinout

One of the most important rules when working with arcade hardware is that a connector fitting physically does not prove that the electrical connections are correct.

Two arcade boards can have edge connectors that appear similar while assigning completely different functions to corresponding contacts.

A position carrying ground on one board could potentially serve another function on different hardware. Connecting an unknown harness based only on physical fit can therefore create an electrical problem rather than proving compatibility.

Always identify the PCB and verify its pinout before applying power.

Dedicated Pre-JAMMA Arcade Connectors

Many classic arcade games were produced before JAMMA became a widely used arcade wiring standard. Manufacturers developed hardware around their own requirements, so cabinets commonly used dedicated wiring arrangements designed for a particular game or related hardware family.

These systems are often described today as pre-JAMMA or dedicated arcade hardware.

A dedicated harness may connect directly to a PCB edge, use several separate connectors, connect multiple boards together, or combine several connection methods.

There is no universal pre-JAMMA pinout. The correct schematic, manual, or reliable documentation for the particular arcade PCB should be used.

What Changed With JAMMA?

JAMMA established a standardized connection arrangement that made it much easier to use compatible arcade PCBs with cabinets wired to the same standard.

Instead of every compatible board requiring a completely different cabinet harness, the standardized JAMMA edge connection assigns common functions to established positions.

That does not mean every arcade PCB is JAMMA, nor does it mean every game function fits within the basic JAMMA standard. Games requiring additional buttons, players, stereo audio, or other features can use supplemental wiring.

For a complete introduction, read What Is a JAMMA Arcade PCB? JAMMA vs. Pre-JAMMA Classic Arcade Hardware .

What Is an Arcade Harness?

The wiring harness is the group of wires and connectors that carries electrical connections between components inside the arcade cabinet.

Depending on the cabinet, the harness can connect the game PCB with the power supply, monitor, speaker, control panel, coin door, test switches, and other equipment.

The edge connector is therefore only one part of the complete cabinet wiring system.

What Does an Arcade Adapter Do?

An arcade wiring adapter allows hardware using one connection arrangement to interface with a cabinet or test setup wired for another arrangement.

A common example is an adapter that allows a dedicated pre-JAMMA arcade PCB to connect to an appropriately configured JAMMA-based test bench or cabinet.

The adapter routes each required signal from its position on one connector arrangement to the appropriate position on the other.

An adapter does not change the underlying PCB into a JAMMA PCB. The original game board still has its original electrical design and pinout; the adapter only provides an interface between the two wiring arrangements.

Connector Orientation Matters

An edge connector must be installed in the correct orientation. Reversing a connector can route power and signals to locations where they do not belong.

Some arcade connectors or adapters may use keys, blocked positions, labels, markings, or physical construction to reduce the chance of incorrect installation. Older or modified cabinets may not always retain those safeguards.

Before disconnecting an unfamiliar original PCB, photograph the existing wiring and connector orientation. Do not rely solely on memory when reinstalling it.

Why Edge Connectors Become Dirty or Unreliable

Original arcade hardware can now be several decades old. PCB edge fingers and harness contacts may have experienced years of heat, oxidation, contamination, repeated connection cycles, mechanical wear, or previous repairs.

Poor contact at the edge connector can contribute to intermittent or unstable operation. A connection carrying significant current can be particularly sensitive to excessive resistance caused by damaged or contaminated contacts.

Connector condition should therefore be part of the inspection process when evaluating an original arcade cabinet or troubleshooting a board that behaves inconsistently.

Burned or Heat-Damaged Edge Connectors

Some vintage arcade boards and harnesses show darkened, discolored, or heat-damaged contacts around power connections.

Heat damage should not simply be ignored because the game still operates. A damaged PCB finger, loose harness contact, poor previous repair, or high-resistance connection can require proper evaluation and repair.

Do not attempt to solve an unknown connector problem by repeatedly reconnecting and powering the hardware. Identify the board, inspect both sides of the connection, and determine the cause first.

Edge Connectors, Conversions, and Bootleg PCBs

Conversion cabinets can make arcade wiring identification more complicated. A cabinet may have been rewired, fitted with an adapter, or modified several times during its operating life.

Bootleg and reproduction boards can introduce additional differences. A board that plays the same game as an original PCB may use a different physical layout, connector arrangement, processor configuration, or pinout.

For this reason, identify the actual PCB rather than assuming compatibility from the cabinet artwork or game title. See Will an Arcade Upgrade Kit Work on a Bootleg, Conversion, or Reproduction PCB? .

Inspect the Connector Before Removing an Original Arcade PCB

Before removing a board from a cabinet, document how every connector is installed. Take clear photographs showing the complete PCB, the edge connector, additional plugs, ribbon cables, grounding wires, adapters, and connector orientation.

Never pull an arcade PCB out by tugging on its wires. Grip the connector body where appropriate and work carefully so the wiring, contacts, and PCB are not damaged.

The complete procedure is covered in How to Safely Remove and Reinstall an Original Arcade PCB .

Does an Edge Connector Determine Upgrade-Kit Compatibility?

No. An edge connector is useful when identifying arcade hardware, but connector style alone does not determine whether a HighScoreSaves upgrade kit is compatible.

Compatibility can depend on the original PCB design, board revision, CPU, CPU socket, ROM configuration, previous repairs, adapters, modifications, and the requirements of the individual kit.

Before ordering an upgrade, use How to Identify Your Original Arcade PCB Before Ordering a Kit as a hardware-identification checklist.

Verify the PCB, Connector, and Pinout Before Applying Power

Arcade edge connectors are the physical bridge between many original game PCBs and the rest of the cabinet, but physical compatibility and electrical compatibility are not the same thing.

Identify the PCB, verify the documented pinout, inspect the edge fingers and harness contacts, confirm orientation, and understand any adapter before applying power.

Those checks are especially important when working with pre-JAMMA hardware, converted cabinets, unfamiliar adapters, reproduction boards, or machines that have accumulated decades of repairs and modifications.

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