I recently needed a new power supply for an Apple IIc to replace a missing one. It’s easy to adapt a modern laptop power brick to work with an Apple IIc. All you need is a pinout. Here’s an Apple IIc power supply pinout.
Apple IIc power supply connector
While modern laptops use a barrel type connector, the Apple IIc uses a 7-pin female DIN connector. If you need to order one, make sure what you order looks like the picture to the right. You need a full-size DIN connector, not a mini. The Apple IIc-compatible Laser 128 uses the same connector and pinout.
While uncommon today, DIN connectors were very popular on 8-bit microcomputers. Using a female connector is a bit unusual, but it prevented you from inserting the power supply connector into one of the serial ports and damaging the computer.
As for the Apple IIc power supply pinout itself, looking at the connector with the plug facing you and the notch facing up, it needs 12-18 volts DC on the two pins farthest on the right (pins 5 and 6), and GND on the two leftmost pins (pins 2 and 3). The two topmost pins and the bottom pin are all unused. Leave them unconnected.
Looking at the back of the Apple IIc, the ground pins are on the right and the power pins are on the left.
Apple IIc power requirements
Apple used 15 volts in the original Apple IIc power supply. But the voltage regulators in the Apple IIc can work with anything from 12 to 18 volts, which is a good thing for us today. 15 volts is a somewhat unusual voltage to find today. It’s much easier to find a 12 or 18 volt supply. An unexpanded Apple IIc only needs 18 watts, so any modern power supply is likely to supply far more power than the Apple IIc needs. There’s no harm in going over on wattage with the IIc.
On your modern power supply, cut off the connector, then attach its power wire to pins 5 and 6 of the DIN connector, and its ground wire to pins 2 and 3 of the DIN connector.
Toning out the Apple IIc power supply pinout
It’s never a bad idea to double check the connections with your multimeter. And it’s very easy to verify them from the Apple IIc itself. The shield connector is connected to ground. So measure for continuity between the shield connector that surrounds the pins and pins 2 and 3. That verifies which are the ground pins, so you can avoid feeding your Apple IIc or Laser 128 reverse polarity.
Some people prefer using a pinout from the perspective of the computer, and some from the perspective of the connector, so I provide both here.