This Palm-Sized Device Solves the C64’s Biggest Problem

The Commodore 64 is undeniably one of the best machines of all time for gaming. The computer can be emulated quite well on modern hardware, but not perfectly. The sound generated by the SID chip, for instance, is never going to be the same without the real hardware. For this reason, lots of people who grew up with a Commodore are now purchasing one on the second-hand market to relive their childhood.

If that’s you, then you might want to think twice before you plug in that beige beauty you just picked up. While the computers themselves have generally held up pretty well over the years, the power supplies have not aged so gracefully. Truth be told, they were never that good to start with. Commodore power supplies are notorious for failing and frying machines with excessive voltage levels.

The best option for powering a vintage machine is to use a brand-new power supply. Since the originals have an unusual connector and supply both 5V DC and 9V AC, you can’t just repurpose an old phone charger — you’ll need something custom-built for the job. YouTuber Side Projects Lab has just created a modern Commodore power supply called PD-64 that is worth checking out. It is ultra-compact and powered via USB Power Delivery (PD), making it convenient for the twenty-first century.

The biggest challenge in the build was supplying both 5V DC and 9V AC simultaneously. Traditional solutions relied on bulky iron-core transformers to generate the low-frequency AC voltage, which is why vintage power bricks were so large and heavy.

The PD-64 takes a completely different approach. Instead of working directly from mains voltage, the unit accepts 12V DC from a modern USB PD adapter. Internally, that voltage is split into separate power stages. A buck converter efficiently generates the 5V DC rail required by the computer, while a far more creative circuit handles the isolated 9V AC output.

To shrink the design down to a palm-sized device, the creator first converts the incoming DC into a 500 kHz high-frequency signal. Operating at such a high frequency allows the use of a tiny planar transformer rather than a massive traditional transformer. After galvanic isolation, the signal is rectified back into DC and then fed into a Class D audio amplifier configured as an inverter. That amplifier synthesizes a clean 9V AC sine wave at precisely 50 Hz or 60 Hz.

Since the circuit is so small, the PD-64 was not built into a big brick. Instead, the case was designed to plug directly into the side of the Commodore 64 and mechanically hold the computer’s original power switch in the ON position. Users power the system using a switch on the PD-64 itself, allowing the device to control startup behavior and suppress potentially damaging voltage spikes before they ever reach the aging hardware.

Side Projects Lab is planning to offer the PD-64 for sale in the near future, so be sure to check back for updates.