Tidy PSU – PD-64 C64 PSU Brings USB PD to Commodore 64

Summary

Side Project’s Lab returns with the PD-64 C64 PSU, a new video focused on a compact USB PD replacement for the original Commodore 64 PSU. The video explains why the classic brick remains a concern for many owners, then shows how PD-64 supplies the voltages the C64 needs without a bulky external unit. Why the Original C64 Brick Causes Concern The Commodore 64 needs two separate feeds: 5V DC and 9V AC at 50 or 60 Hz. That AC line matters, since the C64 uses its frequency for the internal time-of-day clock. Older PSU designs rely on a transformer to create the 9V AC line. Low-frequency AC requires a larger transformer, which explains the size and weight of many classic and modern C64 supplies. PD-64 takes a different route. How PD-64 Works The PD-64 runs from a USB PD wall adapter and requests 12V DC. From there, it creates the 5V DC output with a step-down DC-DC converter. For the AC side, the board generates a 500 kHz signal and sends it through a small planar transformer. That keeps the AC section galvanically isolated from the DC section. The output then gets rectified to around 13V DC, which feeds a high-output class D amplifier. That amplifier produces the final 9V AC at either 50 Hz or 60 Hz. The result is a small unit that plugs directly into the C64. A rear switch selects the correct AC frequency for the user’s region. Protection Features and GitHub Files The video gives safety plenty of attention. PD-64 uses electronic fuses on both outputs, short-circuit protection, under-voltage protection, over-voltage protection, and thermal shutdown. The front bump holds the C64 switch on, so the rear switch controls startup from the PSU itself. The GitHub page confirms that PD-64 supplies 5V DC at 2A and true galvanically insulated 9V AC at 1A. It also notes that the USB PD wall adapter is sold separately. Schematics and 3D case files are available, though the full design is not public. C64 users interested in modern hardware should watch the full Side Project’s Lab vid...