A vintage computing enthusiast and fan of retro Apple computers has built the first new Apple Macintosh Plus compatible clone in 34 years. The electrical engineer adds it to their previous work cloning the Apple Lisa but says the job’s not done yet.
Posting on Mastodon as DosFox, the enthusiast said they had been trying to bring this project to fruition for years. “Theoretically this project is even older than the Lisa project — I only built the Lisa as I couldn’t build a Macintosh,” they wrote. Apparently, building the Lisa was the necessary jump-start since they successfully booted the Macintosh Plus clone almost precisely a year after first booting up the Lisa.
The project required a fair bit of trial and error, and there’s still work to do. One of the integrated circuits on the original Macintosh Plus board was mislabeled as a 74LS257 when it was a 74F253 IC. They’re also still trying to resurrect the Plus’s Sony SND IC, which handles audio amplification and power-on reset.
More importantly, DosFox discovered that even though their Raspberry Pi Pico scan converter was reported to work with the Macintosh Plus, they could not get any video from it. To boot up and see if the clone was functional, DosFox used AppleTalk remote control software Timbuktu to access the vintage clone.
DosFox still considers the project a success, producing a clone fully compatible with any software or hardware designed initially for a genuine Macintosh Plus. The original Macintosh Plus was launched in 1986 to follow the Lisa. It is widely recognized as the first PC to feature a graphical user interface and be targeted at a mass-market audience.
The original Macintosh Plus came with 1MB of RAM, which could be upgraded to 4MB using SIMM modules. It shipped as an all-in-one design, which placed the computer inside a housing with a compact CRT display. Although all of the original designs have been long discontinued, other enthusiasts have poked and prodded at their components for years.
As a result, the internal components of the Macintosh Plus are understood well enough for DosFox to reverse engineer the design and create the clone, just as they did with the Apple Lisa. Once all the wrinkles are ironed out, DosFox will likely release schematics and instructions for other enthusiasts to duplicate their efforts.
