In his latest video, Hans Campbell embarks on a deep-dive repair of a rare Commodore 64 motherboard, the ASSY 250425. This isn’t just any board—it’s one Hans has long searched for to add to his personal collection. Known as one of the last revisions of the breadbin-style C64 boards, this version was released around 1986–87, near the end of the system’s retail lifespan. With his signature mix of engineering insight and vintage flair, Hans walks viewers through both the history and hardware upgrades of this iconic motherboard.
The Commodore 64 motherboard Hans is repairing has several unique characteristics. It features a consolidated custom MOS chip that replaces several discrete components, improving efficiency but reducing repairability. Notably, Commodore also rotated the VIC-II chip and removed the RF shielding—leading to more heat buildup and potential chip failure. Hans carefully explains common failure points in the ASSY 250425, including the VIC-II and color RAM chips, along with swapped SID and PLA socket positions that could easily trip up the unaware.
Throughout the episode, Hans emphasizes the importance of high-quality components in retro restorations. He swaps out the aging voltage regulators for new ones, applies Arctic Silver for heat transfer, and replaces old electrolytics and disc caps with high-end metallized film capacitors. NEC-made DRAMs on this board earn praise for their durability and quality, with Hans noting their low failure rate.
Of course, it wouldn’t be a Hans Campbell restoration without a little customization. Hans plans to install a Nano SwinSID chip for superior sound quality, swap in a right-angle cartridge port for ergonomic access, and eventually mount this board in a PC-style tower case powered by a modern ATX supply. That’s right—he’s turning a Commodore 64 motherboard into a full-featured tower system, complete with cartridge access from the top, internal cooling, and sleek case mods.
This video offers more than just a repair—it’s a loving tribute to the 250425 revision and a blueprint for building the ultimate modern-retro hybrid C64.
