Amiga 500 Mainboard Gets an Open Hardware Remake with the Rämixx500 Project

Amiga 500 fans know there is a dwindling supply of original parts for their beloved platform. Thanks to Open Retro Works, the mainboard may no longer be in limited supply. Using KiCad, they recreated the original circuit board as an open hardware project called Rämixx500.

The process started with redrawing the schematic and then painstakingly recreating the circuit board. Special attention went to placement-specific features like screw holes and the I/O connectors.

The project's motivation comes from existing boards getting destroyed by leaking batteries:

Many Amiga 500+ computers are suffering an early death because of the built-in barrel battery that powers their internal real-time clocks. Such batteries have long exceeded their planned lives and in many cases have started to leak alkaline liquids over the mainboard, corroding copper traces and destroying components.

On the GitHub project, you can find a list of deliberate changes from the original board's layout. One example, which should not affect functionality, is the extended pads for DIP-style chips. A change like that makes (hand) soldering sockets to the board easier.

If you're thinking about building your own Rämixx500 board, there are a few things to know. First, the current board design has not been tested yet. So keep that in mind before you send it out to a PCB house. And second, you may have trouble sourcing modern equivalents for some components. For example, the non-standard DB-23 connectors for the video and floppy may have to come from an older board. And like many computers from the Amiga 500's era, the axial capacitors popular back then, are not usually available now.

Getting a Rämixx500-based system up and running may need some tweaks. Again, the GitHub project page has some instructions that may be necessary. Open Retro Works hopes that anyone who takes on the task will report their success or issues.

Even as complete as this board looks, there is already a laundry list of enhancement ideas available. The next revision, or design, may deviate from the original to include modern features like upgraded RAM, acceleration, activity lights, and USB ports.

It does not appear that Open Retro Works plans to sell the board. Their license allows for others to produce and sell it. Though, keep in mind, you need to test it first.

To keep track of the project, get the KiCad files, and see the current documentation, check out the Rämixx500 GitHub page.