Amiga 5 pin power supply connector.
The Amiga 500, 500+, 600, and 1200 all share the same external power connector: a 5-pin square DIN socket (designated CN8 in the A500 Plus service manual) that carries regulated DC rails directly from the external brick-style power supply unit. Introduced with the original Amiga 500 and retained across the budget Amiga range through the early 1990s, the connector delivers +5 V, +12 V, and −12 V simultaneously, unlike the single-voltage designs used on contemporary 8-bit computers. Although the connector is mechanically identical to the one used on the Commodore 128, the voltage assignments are entirely different, making the two PSUs electrically incompatible.
| Pin | Name |
|---|---|
| 1 | +5V |
| 2 | Shield Ground |
| 3 | +12V |
| 4 | Signal Ground |
| 5 | -12V |
Signals
- +5V — main logic supply for the CPU, chipset, RAM, and most onboard ICs; rated at 4.3 A on the A500 PSU.
- Shield Ground — earth reference connected to the metal shell of the DIN connector, providing electromagnetic shielding.
- +12V — secondary positive supply for disk-drive motors and audio amplifier; rated at 1.0 A on the A500 PSU.
- Signal Ground — PCB reference ground for all DC signal returns.
- -12V — negative rail used by certain interface and audio circuits; rated at 0.1 A on the A500 PSU.
Notes
The connector is a 5-pin square (not round) DIN, sometimes described as a “5 PIN SQ DIN POWER” in official Commodore schematics. The shell of the connector carries Shield Ground (pin 2) separately from Signal Ground (pin 4), which is the PCB reference. The A500 Plus service manual (PN-400420-01) designates this connector CN8 on schematic sheet 10.
The Commodore Amiga A500/A2000 Technical Reference Manual notes that the A500 power supply design is “similar to that of the C128”, reflecting the shared connector form factor. However, the pin assignments are completely different: the C128 delivers +5 V on pin 1 and 9 VAC on pins 3 and 5, whereas the Amiga delivers three DC rails. Connecting a C128 power supply to an Amiga 500 (or vice versa) will destroy the computer.
Expansion draw ratings for the A500 Plus internal expansion slot are limited to +5 VDC at 330 mA maximum and +12 VDC at 15 mA maximum, as specified in the A500 Plus Service Manual.