Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
Click any pin to view its signal assignment, electrical spec, and wire colour.
Supported Systems / Found On — Retro Machine Hubs
This connector is used on the following retro computer systems. Click any colour-coded badge below to open its full board-level repair, diagnostic, and schematic Machine Hub:
Connector Specifications
Connector Type
7-Pin Proprietary Keyed Nintendo Socket (2 columns: 4 pins left, 3 pins right)
Shift Register
CMOS CD4021B 8-Bit Parallel-In / Serial-Out inside controller (+5V, Active-Low buttons)
Bit Order (D0)
Bit 0=A, Bit 1=B, Bit 2=Select, Bit 3=Start, Bit 4=Up, Bit 5=Down, Bit 6=Left, Bit 7=Right
Lightgun / Aux
Pin 6 (D3 = Zapper Light Sensor) & Pin 7 (D4 = Zapper Trigger / Power Pad)
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| 1 | GND (0 V Ground) | GND | 0 V Common Ground Return | Brown |
| 2 | CLOCK (CPU Out) | Out | Shift Clock from 74HC368 / 2A03 ($4016/$4017 read pulse) | Red |
| 3 | LATCH (OUT0 Strobe) | Out | Parallel Load Strobe from 2A03 Pin 39 (OUT0 write to $4016) | Orange |
| 4 | DATA D0 (Serial In) | In | Serial Button Data Output from CD4021 Pin 3 (Q8) to 74HC368 | Yellow |
| 5 | NC (No Connection) | NC | Unconnected on standard NES (sometimes D2 on Famicom expansion adapters) | NC |
| 6 | DATA D3 (Zapper Light) | In | Auxiliary Input D3 — Zapper Photodiode Sense / Arkanoid Vaus / Power Pad | Blue (Zapper / Power Pad) |
| 7 | +5V DC (VCC) | Pwr | +5.0 V DC Regulated Supply (Note: Pin 5/6/7 numbering varies by diagram; corner pin opposite GND is +5V, middle-right is D4 Trigger) | White (+5V) / Purple (D4 Trigger) |
Troubleshooting Dead NES Controllers & Zapper Lightguns
Instead of using one wire per button like the Atari 2600 DB9 port, the Nintendo NES uses a CMOS 4021 (CD4021B) 8-bit parallel-in/serial-out shift register inside each NES-004 gamepad. Every 60Hz/50Hz frame, the 2A03 CPU pulses the LATCH line (Pin 3) for 12 µs to freeze all 8 button states, then pulses the CLOCK line (Pin 2) 8 times while reading the serial stream on DATA D0 (Pin 4) in the fixed order: A, B, Select, Start, Up, Down, Left, Right.
- All Buttons Dead on Port 1 or Port 2: Inside the NES, both controller ports pass through two 74HC368 hex inverting buffers (U7 and U8 on the NES motherboard) before reaching the 2A03 CPU. Static electricity from fingers touching the controller pins frequently blows U7 or U8 — socket and replace the 74HC368!
- Standard NES-004 Wire Colour Code: Brown = GND, White = +5V, Red = Clock, Orange = Latch, Yellow = Data (D0). If a controller acts as if the "A" button or all buttons are held down continuously, check for a broken Orange (Latch) or White (+5V) wire right where the cord exits the gamepad shell.
- Why the NES Zapper Only Works on a 15 kHz CRT TV: The Zapper photodiode on D3 checks that the screen goes black for one frame and then flashes white on the target sprite during the exact CRT raster scanline; modern LCDs and HDMI upscalers add 1–3 frames of latency, breaking the frame-sync window.