What started as another piece of the Macintosh Classic II retrofit turned into most of my weekend being spent designing, printing, test-fitting, changing things, printing them again, and eventually getting to the point where this thing is starting to look like an actual computer again.
The whole idea behind this project has been to keep the original Macintosh Classic II case while building a modern internal mounting system that doesn’t permanently lock the machine into one particular Raspberry Pi or configuration. Instead of simply screwing components wherever they happen to fit, I’ve been working on a modular rail system in OpenSCAD that gives me a framework to mount the Raspberry Pi, storage, cooling, and eventually the power hardware inside the original chassis.
Designing the Rail System
A large part of the weekend was spent working through the Raspberry Pi mounting plate and the dovetail rail system.
The advantage of doing this in OpenSCAD is that I can build individual parts as modules, position them where I need them, and then make relatively small changes without having to redesign the entire assembly. That became particularly useful when working out the Raspberry Pi mounting holes and realizing that I wanted the plate to be adaptable depending on which direction the Pi needs to face.
I’ve also been building the system around the idea that the rails themselves become the permanent infrastructure inside the Macintosh. The individual pieces can then slide onto those rails and be changed later.
That becomes important because I’m not necessarily going to leave a Raspberry Pi 4 in this machine forever.
The Pi 4 and Pi 5 use the same basic four-hole mounting pattern, meaning the mounting plate I’ve already designed can also become the basis for a Pi 5 installation. The connectors, cooling requirements, and other components are different, but I don’t have to redesign the basic mounting system just to change boards.
Cooling the Little Macintosh
Cooling has been another part of the design.
I’ve been working with a 60 mm × 60 mm × 15 mm Noctua fan and a printed spacer/chimney arrangement that makes use of the existing opening in the Macintosh chassis. Instead of having a fan randomly circulating warm air inside the case, the goal is to create an intentional airflow path.
That is particularly important if I eventually move this over to a Pi 5 with an SSD. There is plenty of physical room inside an old compact Macintosh, but once you start putting modern hardware into it, you still have to think about where the heat is actually going.
The rail system also helps here because I can keep the computer and storage hardware positioned without blocking that airflow.
And Then the Screen Came to Life
The part that made all of this feel considerably more real was finally seeing the LCD installed from the front with Ubuntu running on it.
From the outside, it is once again recognizably a Macintosh Classic II.
Inside is an entirely different story.
The LCD controller is mounted behind the display, the Raspberry Pi assembly sits farther down in the chassis, and the rail system gives me a way of supporting everything without turning the inside of the machine into one giant permanently mounted assembly.
There is still cable management to finish, but at this stage I actually want some of the project photographs to show that process. A retrofit like this doesn’t magically go from CAD drawing to perfectly finished computer. There are ribbon cables, USB cables, power wiring, test fittings, pieces that get moved, and designs that get changed after you see how they behave in the real chassis.
That’s part of building it.
The Next Problem: Power
Getting everything installed also exposed the next issue I need to deal with: power.
Once I’m talking about moving to a Raspberry Pi 5 while also operating a SATA SSD through USB, the power requirements start becoming much more significant.
The SSD isn’t just storage sitting passively in the machine. The USB interface and drive require power, the Pi requires power, the display hardware needs power, and the cooling system adds another load.
So this has reached the point where proper Pi 5-level power isn’t optional. I don’t want a system that appears to work until the SSD starts doing something substantial and suddenly the Pi experiences an undervoltage condition or the USB device resets.
That’s especially important if the SSD eventually becomes the boot drive.
Moving Ubuntu to the SSD
That is probably another change coming to this machine.
Right now, moving the operating system from the SD card to the SSD would make a lot of sense. It should provide a better long-term storage solution and take advantage of the drive that’s already going to be installed in the computer.
There’s just one minor problem:
I need to get the stuff that’s already on the SSD off the SSD first.
Because naturally the drive that would make the perfect system drive is also a drive I’m already using.
So before I start repartitioning, imaging, or otherwise doing anything destructive to it, the existing data has to be moved somewhere else. Once that’s done, I can look at either cloning the existing Ubuntu installation or setting up the SSD as the primary boot device.
Updating the Thingiverse Project
I’ve also been updating the Thingiverse project with new photographs showing where the design has gotten.
I wanted to include both sides of the project.
One photograph shows the Classic II from the front with the LCD installed and Ubuntu actually running. The other shows what is happening behind the scenes: the controller, Raspberry Pi hardware, wiring, mounting system, and the amount of space that is still available inside the case.
There is also a separate printable adapter being used to mount the modern LCD into the original Macintosh display opening.
LCD Display Adapter:
Macintosh Classic LCD Display Adapter on Thingiverse
Keeping that as a separate design makes sense because somebody may want the LCD conversion without using my Raspberry Pi rail system, or may want to use the rail system with an entirely different display arrangement.
Where It Stands After the Weekend
At the beginning of this project, most of this existed as measurements, OpenSCAD geometry, and an idea of how I wanted things to fit.
Now I have physical rails. I have a Raspberry Pi mounting system. I’ve been working through the cooling arrangement. The LCD is mounted. Ubuntu is running on the machine. And I have photographs showing that the parts I’ve been designing actually work inside a real Macintosh Classic II chassis.
There are still things to solve. Power distribution needs to be finalized. The SSD needs to be dealt with. Cable routing can be cleaned up. And there are undoubtedly going to be more pieces that I decide need to be redesigned after staring at the inside of this thing for another few hours.
But that’s also what I spent the weekend doing:
Design it. Print it. Find out what I did wrong. Change it. Print it again. Install it. Then find the next problem.
For a project like this, that’s pretty much the process.
Short description:
This weekend the Macintosh Classic II Raspberry Pi conversion moved from mostly CAD and individual printed parts to a functioning computer. I worked on the modular dovetail rail system, Raspberry Pi mounting plate, Noctua cooling arrangement, LCD installation, and storage layout while continuing to test everything inside the original chassis. Ubuntu is now running on the installed LCD, and the next major jobs are proper Pi 5-level power, SSD boot storage, and final cable management.
Hashtags:
#MacintoshClassicII #RaspberryPi #3DPrinting #OpenSCAD #RetroComputing #MakerProject