A smaller Nomad-style GoaC portable.

New Project Time! We have recently added the GN-Twin in our possession, which is essentially the more familiar FC-Twin (NES and SNES clone) but with a Genesis and NES combination instead. I needed an NES 72-pin replacement connector off of the NES side, so might as well do something with the other. Even though Genesis clones aren’t that great at all in a general sense (this one is no exception), yet it still works so should be put to some use. The board is actually pretty small so hey, how about a 3D printed Mini Sega Nomad portable?


The aforementioned GN-Twin by Yobo, along with the FC-Twin, were in competition with the Retro Duo. Original Hardware always trumps Clone Hardware, but the price, availability, and smaller motherboard sizes sometimes are worth the trade-off for mods, portables, and casual nostalgic gaming. The console at the thrift was cheaper than the 72-pin NES connector that I needed, and the bonus Genesis side was a nice bonus for tinkering projects.


A quick overview of all the parts for this project. A 2.5″ screen will be used, and an external Sony Camera Battery for power to imitate the external battery pack from the Nomad. The GN-Twin consists of four separate motherboads: the Power and A/V section, the Genesis motherboard, the NES motherboard (with cartridge slot already sacrificed for a different project), and finally the section for the controller ports. The A/V and Controller boards can be omitted, however due to the controller signals being decoded from NES to Genesis, the NES motherboard area cannot. Luckily it is smaller than the Genesis board and can be folded flat underneath it. You may notice the SNES controller ports in that picture as well. More on that next.


The GN-Twin Controller ports may look like a Genesis, or even a Famicom connection, but it is neither of those. Luckily Stone Age Gamer did all the legwork for a Pinout to convert the FC3 (a Snes/NES dual clone console) controller port for the SNES controller. Said method will also work for the GN-Twin here, albeit with strange button mapping, but we’ll be relocating the controller anyways so it is not an issue here.

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Having *Just* 64 Pins on the Genesis cartslots so not as bad as the NES (72 Pin Connector) or the Jaguar (108!) but still kind of agonizing. I split wiring the slot up over 4 sessions (front side of motherboard, back side of motherboard, front side of connector, and back side of connector) so I wouldn’t go completely insane. I’m sure I’ll look back on this and laugh while doing these in my sleep as technology and mods advance. Rejoice! That it worked on the first try.


To save space in the case, we were able to omit 2 of the 4 GN-Twin boards, removing the A/V Board in the back and the Controller Ports Board in the front, while keeping the Genesis board (obviously) and the NES board. The NES board has three chips that filter the controller inputs, so we decided to keep that board. It probably could be removed with a little more research seperating the controller chips onto it’s own board, but the outcome would probably be more bulky with all the wiring. Instead, the NES board was folded over to the back side of the Genesis board and soldered together using header pins, thus also eliminating any wire bloat between them.

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With all the electronics more or less under control, it’s time to work on the 3D Printed case. Keep it right here for Part 2 where we will design, test, print it all out and assemble the Nomad Jr. Case.















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