Retrocomputing enthusiast ARC Javmaster has returned with part two of his Adventures in Retrocomputing series, showcasing the rare Mimic Spartan — an Apple II clone that integrates a Commodore 64 as both a functional keyboard and a second computer. This unusual combination allows a user to switch between the Apple II environment and native C64 mode, creating a versatile hybrid that stands apart from standard vintage setups.
After resolving earlier hardware issues, Javmaster’s latest update delivers the first successful test run of both systems, offering a closer look at this rare piece of computing history.
Getting the Commodore 64 Back in Action
The Mimic Spartan relies on a working Commodore 64 to operate as both an Apple II input device and a standalone C64. In the first installment, Javmaster’s original C64 refused to display video, despite showing a power LED. Replacement parts didn’t resolve the issue, so a working unit was sourced.
Once the new C64 was connected, it powered up without issue. Basic functions tested fine, including text input and program loading from an older SD cartridge adapter. While the cartridge exhibited minor graphical glitches, the test confirmed that the C64 hardware was functioning well enough to integrate into the Spartan system.
Connecting to the Spartan
With the C64 verified, Javmaster moved to integrate it into the Mimic Spartan enclosure. The process involved reconnecting internal ribbon cables between the Spartan’s rear connectors and the Commodore. These short cables required careful handling to avoid stress on the ports.
Once secured, a power-on test revealed the Spartan interface on screen. Audio worked, and a newly installed dual-color LED mod switched between green for Apple II mode and red for C64 mode, providing a simple visual cue for active system status.
Switching Between Systems
One of the Spartan’s most intriguing features is its quick-switch capability between Apple II and Commodore 64 modes. Using a combination of shift keys and function commands, Javmaster successfully toggled between the two platforms.
While the Apple II side displayed clean video output, the C64 mode exhibited distortion, indicating a potential cable or connection issue. Despite the imperfect display, input and sound worked as expected, confirming that both environments were operational.
Adding Storage with Modern Solutions
The Mimic Spartan was originally designed to interface with Apple II disk drives, but finding and maintaining these vintage drives can be a challenge. To modernize the setup, Javmaster explored drive emulation hardware.
His first attempt used an XDrive card, a modern storage emulator for Apple II systems. While the XDrive is fully compatible with the Apple IIe and IIgs, it appeared too advanced for the Spartan’s Apple II Plus–class hardware and failed to initialize.
Next, Javmaster installed a Booti drive emulator created by Mark Joitis. The Booti allows Apple II systems to load software directly from USB storage. This test succeeded — the Apple II environment booted, and storage functions worked without requiring legacy drives. The result was a fully functional Apple II mode with solid-state storage, bypassing the need for aging floppy media.
Troubleshooting and Next Steps
The main issue remaining is the distorted video output in C64 mode. Since the Apple II side displays cleanly, the fault may be isolated to the cable between the C64 motherboard and Spartan video interface. Possible fixes include re-seating or replacing this cable.
Future plans include sourcing additional drive emulation hardware, such as the Floppy Emu, to further streamline software access. With a working Apple II setup, Javmaster now aims to fully restore the C64 side, ensuring both systems operate flawlessly within the Spartan chassis.
A Rare Hybrid Worth Preserving
The Mimic Spartan is more than just an Apple II clone — it’s a unique hardware solution that merged two competing 8-bit systems into a single workstation. In the early 1980s, this flexibility offered practical benefits: Apple II users could run Commodore software without owning a second full computer, and vice versa.
Today, surviving units are scarce, making each working restoration an important piece of computing history. By integrating modern storage solutions like the Booti, the Spartan can remain practical for demonstrations, development, and retro gaming well into the future.
Watch the Full Test and Setup
Javmaster’s detailed walkthrough is more than just a repair log — it’s a rare opportunity to see the Mimic Spartan in operation, switching between Apple II and Commodore 64 modes in real time. The video captures the quirks, technical hurdles, and satisfying successes that come with restoring such an unconventional piece of vintage hardware.
Viewers will see the complete process: unboxing the working C64, connecting it to the Spartan, experimenting with storage emulators, and troubleshooting video issues. For those interested in retrocomputing hardware, it’s a hands-on look at a hybrid system few have encountered in person.
To view Part 1 of this series Click Here.
