Someone Built The Commodore 64 Mostly From New Parts.


VTF?! The Commodore 64, the best-selling home desktop computer of all time, remains a favorite even 40 years after its debut. An invariable sign of its popularity is the dedication of the users who today service the C64 hardware and software. A self-made project to rebuild the system demonstrates the depth of this community.

The modder has successfully assembled a brand new working Commodore 64, using mostly new components. The project documentation contains useful information for those who are interested in repairing or other studies of the system equipment.

Modder Celso Martinho built a copy of the C64 almost from scratch to test his skills in a retro computer. Without stopping at restoring the system as it was in 1982, Martinho decided to use as much new material as possible and make his Frankenstein 64 easily repairable.

The printed circuit board, resistors, capacitors, passive semiconductors, board connectors, common logic chips and IC connectors are all new. Most of the new parts were taken from the Commodore 64 parts kit, which users usually buy to repair older systems.

Martinho has found modern substitutes for some other components. He used an alternative to the C64 programmable logic matrix, which connects his processor to memory, because it is one of the parts that usually dies over time. This is also a part that another modder has previously reconstructed so that users can create new models today.

Martinho did something similar for the C64 sound chip and the Philips monitor power switch. In addition, new power supply replacements are safer than the original.

Enthusiasts can buy modern replacements for the C64 case because someone discovered the original shapes in 2014. There are several colors available today, and Martinho chose the transparent version.

However, some parts are no longer manufactured, and therefore they can only be found in old equipment. Martinho either bought them online or saved them from his old, broken C64.

These include two complex MOS 6526 interface adapters, a MOS 6569 Video Interface Chip II (VIC-II) C64 graphics chip, eight 4164 DRAM chips, a Motorola MC4044 and a C64 MSO 6510 processor. There are FPGA-based substitutes for the VIC-II, but Martinho does not consider them ready for prime-time use.

The project also involves three ROM chips without modern replacements: two MOS 2364 ROMs for the Basic interpreter and the Kernal operating system, as well as a ROM with the MOS 2332 character set. To do this, Martinho recorded the original C64 ROM dumps in EPROMS. He also removed and cleaned the key caps from the original C64 keyboard.

Unfortunately, Frankenstein 64 did not reproduce a playable image when Martinho was first turned on. After months of trial and error, he fixed the problem by replacing the 74LS193 divider. Finally, Martinho tested the system with a diagnostic cartridge, which worked flawlessly, as did all the games he played on it.

Casual users planning to return to C64 will most likely want to buy the 2019 reissue of Retro Games Ltd. It comes with all the basic features of the original, 64 packaged games, a USB port for downloading new games and firmware (including home software) and an HDMI output for modern displays.


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