JAMMA Wiring & PCB Guide for Arcade Machines
JAMMA Wiring & PCB Guide
JAMMA (Japan Amusement Machine and Marketing Association) is the industry-standard wiring harness used in most arcade game cabinets. This guide explains the JAMMA standard, how to connect PCBs to a JAMMA harness, and how to troubleshoot common wiring issues.
What is JAMMA?
JAMMA is a standardized 56-pin edge connector that defines how arcade game PCBs connect to a cabinet’s power supply, monitor, controls, coin mechanism, and speakers. Most classic and modern arcade PCBs use the JAMMA standard, making it easy to swap game boards between compatible cabinets.
JAMMA Pinout Reference
The JAMMA connector has 28 pins on each side (Side A and Side B). Key pin assignments:
| Pin | Side A | Side B |
|---|---|---|
| 1 | Ground | Ground |
| 2 | Ground | Ground |
| 3 | +5V | +5V |
| 4 | +5V | +5V |
| 5 | +12V | +12V |
| 6 | -5V | (Key/Notch) |
| 7 | Coin Counter 1 | Coin Counter 2 |
| 8 | Coin Lockout 1 | Coin Lockout 2 |
| 9 | Speaker (+) | Speaker (-) |
| 10 | Video Green | Video Red |
| 11 | Video Sync | Video Blue |
| 12 | Video Ground | Service Switch |
| 13 | Test Switch | Tilt Switch |
| 14 | Coin Switch 1 | Coin Switch 2 |
| 15 | 1P Start | 2P Start |
| 16 | 1P Up | 2P Up |
| 17 | 1P Down | 2P Down |
| 18 | 1P Left | 2P Left |
| 19 | 1P Right | 2P Right |
| 20 | 1P Button 1 | 2P Button 1 |
| 21 | 1P Button 2 | 2P Button 2 |
| 22 | 1P Button 3 | 2P Button 3 |
| 23–28 | Ground | Ground |
Connecting a PCB to a JAMMA Harness
- Power off the cabinet completely before handling any PCB or wiring
- Align the PCB’s edge connector with the JAMMA harness connector — the key notch prevents incorrect insertion
- Firmly press the PCB into the connector until fully seated
- Secure the PCB with the mounting bracket if provided
- Connect any additional connectors (kick harness for extra buttons, stereo audio, etc.)
- Power on and test all inputs and outputs
Power Supply Requirements
JAMMA cabinets require a switching power supply providing:
- +5V: Main logic power for the PCB (most critical — must be stable)
- +12V: Monitor deflection, audio amplifier, and some peripherals
- -5V: Required by some older PCBs (not all modern boards need this)
Use a quality arcade power supply rated for at least 10A on the +5V rail. Voltage fluctuations can cause game resets or PCB damage.
Common JAMMA Wiring Issues & Fixes
- No video output: Check video ground connection and RGB signal wires. Verify monitor sync polarity matches the PCB output.
- No sound: Check speaker wiring polarity. Some PCBs require a volume potentiometer on the audio line.
- Controls not responding: Verify ground connections on all control inputs. JAMMA controls are active-low — they trigger when connected to ground.
- Coin mechanism not registering: Check coin switch wiring to pins 14A/14B. Verify coin counter wiring if using a counter.
- PCB resetting randomly: Low +5V voltage is the most common cause. Adjust the power supply voltage trimmer to 5.1–5.2V at the PCB connector.
Non-JAMMA Arcade PCBs
Not all arcade PCBs use the JAMMA standard. Some require:
- Kick harness: Additional connector for extra buttons (common on fighting game PCBs)
- Proprietary connectors: Some manufacturers use custom wiring (e.g., Sega, Namco system boards)
- JAMMA adapters: Available for many non-JAMMA PCBs to allow use in standard JAMMA cabinets
Frequently Asked Questions
Is JAMMA compatible with all arcade PCBs?
Most classic arcade PCBs from the 1980s–2000s use the JAMMA standard. Modern arcade hardware may use proprietary connectors, but JAMMA adapters are available for many popular systems.
Can I use a JAMMA harness with a claw machine control board?
Claw machine control boards use their own proprietary connectors and are not JAMMA-compatible. JAMMA is specific to video arcade game cabinets. For claw machine wiring, refer to your machine’s specific wiring diagram.
What voltage should my +5V rail be set to?
Set the +5V rail to 5.1–5.2V measured at the PCB connector (not at the power supply output). Voltage drop across the harness means the supply output should be slightly higher than 5.0V.