A Complete Shell Replacement For:

Revision: 4

DOWNLOAD THE UPDATE NOTES HERE

THE MOST ACCURATE REPLICA OF THE SEGA NEPTUNE PROTOTYPE!

CHECK OUT EXPERIENCED BUILDERS OF THE NEPTUNE IN THE BELOW LINKS...

Twitter: @DVIZIX Instagram: DIVIZIX

The SEGA Neptune. Originally conceived as a Genesis and 32X system combined into a single console, it unfortunately never saw the light of day. As a huge SEGA fan, my goal is to bring this amazing system back to life by providing a replacement shell that can be swapped with a standard US or EU Genesis/Megadrive 2.

Simply unscrew your existing Genesis 2 console (preferably one that has been damaged externally) and replace the below listed parts with my new 3D printed offerings to turn your console into a NEPTUNE!!

To ensure you are selecting the correct list of parts you first need to know what type of build you want to create.

Here are some examples...

1. The MEGADRIVE / GENESIS 2 NEPTUNE - For those that just want to transfer their existing Megadrive / Genesis 2 PCB into the Neptune shell.
2. The MODDED (LONGHORN / MODULAR) NEPTUNE - This is for people who have actually created a working Neptune by combining a Megadrive / Genesis 2 PCB with a 32X and wish to place it into the Neptune shell. Most common mods are produced using the "Longhorn" method or the "modular" method.
3. The COSAM NEPTUNE - This is for people that have produced a working Neptune using COSAM's own custom PCB and wish to place it into the Neptune shell. These boards require the components from an existing Megadrive / Genesis 2 and 32X.
4. NEW BUILD - In development.

Decided what build you want to make? GREAT!! Now lets see what parts we need...

These diagrams show the list of parts and will help show where they go and what they do.

Also you can download the corresponding list for each build.

**WARNING!** REV.4 ITEMS CANNOT BE USED WITH OLDER REVISIONS.

Download List for MEGADRIVE / GENESIS 2 NEPTUNE here.

Download List for MODDED (LONGHORN / MODULAR) NEPTUNE here.

Download List for COSAM NEPTUNE here.

Download List Coming Soon...

Since the 32X and the Neptune was designed by SEGA of America the shell has a western style cartridge slot. My intention is to replicate the prototype as accurately as possible. However, this means it will not accept Japanese Megadrive game cartridges.

After receiving requests for Japanese cart compatibility I have decided to create a new top shell with modified dust flaps for people to print.

CLICK HERE FOR JAPANESE TOP SHELL

This new slot has been designed to match the Japanese Super 32X slot.

Please ensure you refer to your chosen build list so you can identify what items need to be replaced with these new Japanese compatible parts.

There are so many amazing modders out there building Neptune's from existing Megadrive / Genesis parts, and some that are doing things totally new! That's the great thing about this ever evolving project. Everyone has their own ideas and vision for what they want from SEGA's elusive prototype. So let it be your own!

Here is a list of people I have been in contact with and I know of:

For a Megadrive or Genesis 2 board combined with a 32X board using the "Longhorn" or "Modular" method, reach out to these great modders who may be open to doing it for you or can direct you to others with the knowledge and the skills:

@infidelity_nes

@PCBAssembly99

For those looking for the complete shell and PCB build:

https://1uprestorations.com/

https://x.com/1uprestorations

Have you heard about COSAM's totally custom Neptune board!? It requires the chips from an original Megadrive / Genesis 2 and a 32X but the end result will provide all the functionality and compatibility that would have been available by the original prototype.

Here is the PCBWay link to the bare board to order yourself: https://www.pcbway.com/project/shareproject/Neptune_console_f136d0e3.html

Here is a link to all the documents and gerbers files: https://github.com/Board-Folk/Neptune

Cosam's Ko-Fi link: https://ko-fi.com/cosam

Reach out to Cosam or these modders known to be working on the board and for information about obtaining your own:

@cosam_the_great

@chris_jh

@A3rgan

The finishing touch to your Neptune build. I have produced .svg files which you can DOWNLOAD HERE and use to source your own from your chosen vendor, or print yourself.

This includes:

Genesis 32X Logo (for US modders)

Megadrive 32X Logo (for UK/EU modders)

Sega Logo

A great vendor I used from the US is Upstate Vinyl

For UK modders, check out Retrofied.uk

• This is a passion project designed by hobbyists for hobbyists. All dimensions have been scaled by me using an EU model Megadrive 2 and has proven to work well with US models. I have not received feedback for any Japanese models.
• Details and quality will depend greatly on the material you choose. So far resin UTR 8360 has proven very reliable.
• For those that wish to just replace the shell of their Genesis/Megadrive 2 please be aware that it will still only continue to function as a Genesis/Megadrive 2. Not sure why I feel I have to say that but people may ask.
• Although this is designed to replicate the Neptune as can best be obtained by images and videos of the prototype, the placement of ports, buttons, size and thickness of the console is still dictated by the internal components of the Genesis 2’s motherboard, current mods and Cosam's motherboard, and therefore a complete imitation of the Neptune may not be 100% achieved... or be possible.
• To integrate a working 32X system within this replacement shell would require the expertise of others (such as the ones I have listed above) with all the associated risks involved.
• The current revision of this Neptune shell is designed to be a replacement for the "push down" on/off button system (EU & US versions), not the "left/right" switch action button that is used on the Japanese version.
• Due to the nature of 3D printing, the freedom of materials on offer and the finishes available, there can be a risk of parts becoming tight in areas where they need to move freely. To avoid this issue I recommend selecting the "recommended" materials and finishes in your build list as these have proven to work successfully. Please also understand you are choosing this shell because you want to achieve the closest possible look of Sega's prototype, but be aware that the position of the Neptune buttons and the switches on the MD/G PCB do not align. My button attachments are designed to make contact with these switches but they will try to pivot and in some cases stick. Any tacky, sticky, rough finish on these parts could make this issue worse and in some cases not work at all.
• Please DO NOT throw away your old Genesis/Megadrive 2 shell. Any examples of these amazing old systems should be preserved and enjoyed hence my goal to create a console that is as easy to modify as it is to revert back to its original form without any destructive methods.

Any feedback would be greatly appreciated to further improve the shell design for future revisions.

Happy Modding!