Naked (And Noisy) NAOMI 2

Merry Christmas!  Just before the madness of the holiday shopping season came around I managed to pick up a nice little Sega Naomi 2 motherboard and a couple of games.  I’d been on the lookout for a while specifically for NAOMI 2 system and found them to be less common at sensible prices compared to the NAOMI 1 systems.  I assume because they are backwards compatible everyone who only has room for one system tries to go for the NAOMI 2.

Regardless, it came, I plugged it in and it works! However, it did make a sound close to that of a jet engine spooling up for takeoff.  Simple enough fix probably. Clean the system up.  This gave me an excuse to take the thing apart and have a look inside.

Getting in to the system is easy.  Turn the system upside down and remove the 8 Philips head screws from the bottom of the case.  There’s no need to detach the plastic feet, they don’t hold the case together.  Lift of the top and I was greeted with this sight:


NAOMI 2 – Dirty MOBO (Top)

This might look OK in the picture but the whole PCB is caked in a sticky kind of black dust and the heat sinks and fans for the CPUs are caked in gunk.  In that picture, looking down at the CPU’s (the two fans) you should be able to see silver through the top… you can’t.  See what I mean?

Dirty CPU


Now that’s just nasty.  It’s sticky and much worse in the center and around the fan.  Blasting some compressed air into the sides and top didn’t really do a heck of a lot.  Some of the dust on the PCB surface dissipated but that was it.  Anyway, there is another fan in the case and that’s a 60mm side vent on the bottom of the case.  That’s the one, anecdotally, responsible for the majority of the noise.  the filter board and the main motherboard just lift right out of the case once the power for the case fan has been detached (top left of the rear of the filter board).

NAOMI2 - Case Bottom

Dirty Bottom

As suspected it and it’s vents were caked in more brown and yellow gunk.  You should be able to get SOME light through the plastic at the back.  Photographing this bit was tricky and, unfortunately, nothing really came out.  The fan assembly and grill slide out and then it’s possible to brush and wash off the gunk and, once dry, give everything a squirt of compressed air to ensure nothing remains.  It now looks much better.  Back to the main motherboard I unscrewed the fans from the tops of the CPU heat sinks and had a look underneath.

CLean and Dirty CPU

Clean Vs Dirty

On the left we have the CPU HS that I’ve cleaned with a soft brush and blasted air through and on the right is what the CPU HS looked like after just a blast of compressed air.  Most of the gunk was stuck in the small fan blowing downwards but there was enough gunk on the heat-sink that cooling would have been impaired.

This and the rest of the board were brushed with a soft, anti-static brush and then compressed air was used to blow everything away (do this outside if you can, it’s horrible).  You’re then left with:

Clean Mobo

Clean Motherboard

A nice clean motherboard.  Now you can see the silver through the tops of the fans and there’s not a trace of the gunk on the main board. Looks much better.  For reference, the bottom of the motherboard wasn’t dirty at all.  It looked like this.

Clean Bottom

Clean Motherboard Bottom

Now, the board plays games as well as it always has but significantly quieter and is no longer noticeable over game play in a living room with regular volume.



About Alec Dunn (LegoYoda)

Alec is an IT Architect focused around large private / hybrid cloud design and automation. He's also a big fan of the 'arcade' culture and games of yesteryear and loves taking things apart to see how they all work.
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