More than once I've talked about the existence of alternative PCBs to repair, restore, and optimize old computers and consoles. The Commodore 64 and the Nintendo NES are two excellent examples. However, the modding universe has crossed an extraordinary threshold of complexity and precision, to the point that it now reproduces systems abandoned by their own manufacturers. That is the case of the Sega Neptune, with a custom motherboard that any enthusiast can build…
A bit of history before we start: The Sega Neptune was announced in early 1995, and its goal was none other than to combine the hardware of the Sega Genesis / Mega Drive with the 32X module, thus creating a 2-in-1 system. Sega said the new Neptune would be ready by fall of that year, but once October appeared on the calendars, it ended up canceled.
Why? Because the company thought it would undermine the marketing of the Sega Saturn (which had debuted in mid-May in the United States, and in early July in Europe), and the price difference between the two consoles was expected to be very small. Fast forward thirty years, and the modders decided to activate Bender mode, creating their own Neptune with gambling and hookers new PCBs and original hardware.
A Sega Neptune Console in 2025
This is possible thanks to the extraordinary work of modder COSAM and other direct collaborators. Tito from the Macho Nacho Productions channel received one of the PCBs and started working, but there are no shortcuts here: All original hardware must be removed from a Genesis / Mega Drive (I imagine one of its most faithful clones could work), and from a 32X module. The PCB includes a new power section, and as if that weren’t enough, there are 3D-printed cases that closely follow the design of the original prototype (the alternative is to use a second-generation Genesis case).
Tito decided to start with the 32X, bathing one of its boards in isopropyl alcohol to simplify the removal of the chips (some of them may have glue on the underside). When working on the Genesis, it's recommended to use Chip Quik or similar, since the factory solder tends to be very stubborn. While Chip Quik requires additional cleaning and is not exactly cheap, everything becomes easier. To remove the ports and connectors, a drill must be used (they come riveted), and other components also need to be removed (resistors, switches).
The rest is… going in the opposite direction, using the new PCB. After confirming the presence of 5V and 3.3V, Tito proceeded to install the chips. This step is not for the faint-hearted or the improvising. A good soldering iron, plenty of flux, a microscope (if possible) and extreme patience are essential to make progress. Fortunately, COSAM created an interactive materials guide that instantly locates the final position for each component.
So, is it worth all that work and money to create a console that never existed? Personally… I think yes. Whoever decides to follow this path will have in their hands a unique system, with excellent compatibility (even supports Sega CD), and a great story to tell.
