Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
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
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| 1 | GND (0 V) | GND | 0 V DC Digital Ground Return (tied internally to Pins 2 & 3) | Black |
| 2 | GND (0 V) | GND | 0 V DC Digital Ground Return | Black |
| 3 | GND (0 V) | GND | 0 V DC Digital Ground Return | Black |
| 4 | NC | NC | Unconnected on C64/VIC-20 (tied to +5 V in some aftermarket PSUs) | NC (or Red +5V parallel) |
| 5 | +5.0V DC | Pwr | +5.0 V DC Regulated Logic Supply (MUST be 4.90–5.20 V DC!) | Red (+5V DC) |
| 6 | 9.0V AC (1) | Pwr | 9.0 V AC Transformer Secondary Winding Leg 1 | Yellow / Brown (9V AC) |
| 7 | 9.0V AC (2) | Pwr | 9.0 V AC Transformer Secondary Winding Leg 2 | Yellow / Blue (9V AC) |
How to Test a C64 / VIC-20 Power Supply with a Multimeter
Used on every Commodore 64 (Breadbin & C64C), the Cost-Reduced (CR) VIC-20 (ASSY 250403), and early production Commodore Plus/4 units, this 7-pin circular DIN carries two separate power domains: a regulated +5.0 V DC rail (Pin 5, 1.5–2.0 A) for the 6510/6502 CPU, PLA, logic, and 4164 DRAMs, and an floating 9.0 V AC transformer secondary (Pins 6 & 7, 1.0 A) used to generate the internal +12 V/+9 V SID/VIC-II rails, the 50/60 Hz CIA Time-of-Day reference, and the cassette motor drive.
- Test 1 (+5 V DC Rail): Set your multimeter to DC Volts. Probe between Pin 5 (+5V) and Pin 2 (GND). A healthy supply reads +4.95 V to +5.20 V DC. If it reads above +5.35 V DC (or 8–10 V DC), retire the brick immediately!
- Test 2 (9 V AC Rail): Switch your multimeter to AC Volts. Probe between Pin 6 and Pin 7. A healthy transformer reads 9.2 V to 10.8 V AC unloaded. If it reads 0 V AC, the internal fuse inside the PSU brick has blown (resulting in no SID sound and no cassette motor on a C64).