Someone Does What SEGA Don’t | COSAM Neptune Project

A modder named COSAM has created a custom motherboard that might just be the missing link in the Sega Neptune mystery. His design allows us to transplant all the proprietary chips from a Sega Genesis and 32X onto a single board—essentially building a true Neptune, just as Sega might have done during its prototyping phase back in 1995. But is the juice worth the squeeze? Let’s find out!

// The Neptune Project:

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Timestamps
0:00 Project Intro
3:57 Parts For Neptune Build
5:33 Neptune Build Tutorial
20:11 Features Overview
23:57 Pros and Cons
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// Intro Music for Retro Renew Series by Matthew McCheskey:
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Disclaimer: This video is only for entertainment purposes. Any injury, damage, or loss that may result from improper use of tools, equipment, or from the information in this video is the sole responsibility of the viewer and is to be used at the discretion of the end user/viewer and not Macho Nacho Productions or Tito Perez. If you are uncertain about any step of the process or feel unsure about your skill level, seek a more authoritative source.

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#Sega #SegaNeptune #MachoNacho

[AdrianSchwartzmann]

Now, I just want to see the reaction of some retired Sega engineer when someone shows up with one of these.

[JaredClarkBoaz]

So glad PCB manufacturing is as accessible as it is.

[LUCASASASUL]

COSAM is a monster. He recreated the Mega CD board, making it possible to revive almost all Mega CDs that today have deteriorated boards, beyond saving.

[fmdof]

i have a complete 32x collection, so something like this is up my alley, but i'm not oblivious to the fact that the 32x is very unloved. So the fact someone took their time to make a board for something very few people would use and enjoy is amazing. Gotta love the passion retro modders have.

[nubatman]

Holy cow! I thought this was covering the layered mod again. This PCB is insane.

[abejavadi]

That purple PCB board is actually really pretty. If I ever did this, this would probably be one of those times I looked for a transparent shell.

[dxr]

Just a little bit of trivia about the Model 1 Sega CD: the actual instructions from Sega back in the day said to remove the rubber feet if using a model 2. So it's not really because of the custom shell, it's a real oversight from Sega back in the day.

[joesaiditstrue]

Sad that we didn't get to see Doom 32X Fusion tested out with the Sega CD

[LordJudgernaut]

This is a super exciting project. A few updates I would like to see though would be:

Neptune Shell:
1) Japanese/custom style cart flaps to allow carts from all regions.
2) Optional 3.5mm headphone jack & stealth volume slider.
3) Dedicated area to install switches (region switch, overclock switch, 32x disable, etc)

Neptune Board:
1) Incorporate Zaxour's 4BP to add S-Video.
2) A switch to disable the 32X, so that CD games can be played from flash carts.
3) Optional 3.5mm headphone jack and volume slider.

Again, still a super exciting and impressive project as is!

[Solmead]

Now to see all three combined (genesis, 32x and saga cd) into one box.

[gibeark]

The talent of not only Steve but also all these MOD engineers is truly a gift to us enthusiasts!

[ChimpyChamp]

Honestly, PCBway has to be the only YouTube sponsor I like, and watch without skipping, they enable so many of my favourite creators to make amazing content like this.

[Yakobu]

Someone needs to come up with a high quality 32X clone or an FPGA so we don't need to pull apart working consoles.

[Klonoa]

i like that now they are two options. One that is easy (32X and basic soldering) and this one. Love your videos man!!!

[MegaManNeo]

If Steve gives us the Nintendo Play Station, this will probably give Neptune a run for its money. Love the end result though, the bgm made this super relaxing to watch.

[alexvalentim]

This is the definition of a passion project

[justanotherchannel]

When ever you are watching a build like this. You start to question yourself... I should have done soldering class at college.

[edmarRE]

One of the best retro technology channels, if not the biggest. This mod is one of the most incredible I've ever seen. These people who dedicate themselves and bring these projects to life really deserve all the honors.

[GreyMatterShades]

This is an amazing project! Congrats to COSAM for his incredible work, and Tito for an awesome build!
Also a great touch to integrate the Triple Bypass into the PCB itself.

[Haulien]

Over the years with full replacement PCBs for various handhelds and retro consoles, this one is by far my favourite. Building something that never existed just because we can.

At least in this small niche area, 2025 is off to a great start.