Naomi main board differences - HOTD2

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Paladin
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Naomi main board differences - HOTD2

Post by Paladin » December 28th, 2012, 2:20 pm

I posted a couple questions on sega-naomi.com, but haven't had anyone answer. That site doesn't appear to have much traffic, so I thought I'd cross post the questions here as well.

I read somewhere that the early metal cage Naomi's have some component differences to the later plastic cased ones. My questions pertain to House of the Dead 2 in particular. I'm planning on making a setup to play all the gun games, but I understand that HOTD2 won't run on the plastic case Naomi's. Can anyone elaborate on this?

I know there's a dedicated BIOS for HOTD2, but I was hoping that I could dual BIOS mod a Naomi to swap between HOTD2 and Japan BIOS chips to run all 5 gun games on one main board (House of the Dead 2, Confidential Mission, Maze of the Kings, Lupin and Death Crimson OX).

I have a white Naomi and I've just bought a metal caged World Series mobo for a pretty good price on eBay. Although it'll be a while before I can afford to buy a HOTD2 cart, I'd still like to know what the deal is with that game/mobo combination.

Another question is what the small 'relay' or 'condenser' board is for on some of the gun game schematics. It looks to have line voltage and ground going to a 4700pf capactitor, but I have no idea what it's for or if it would be needed in my planned setup.

At this point I'm thinking of making a pedestal with all the hardware and guns in it that I can wheel up to an arcade cabinet or my HD TV. It would have power, VGA and audio RCA cables that could be plugged in to play the game on different platforms. The gun sensors may be a problem, either some kind of temporary portable adjustable setup or one set of sensors permanently mounted in a cabinet and another that could be setup around the TV when needed.

Any information would be appreciated!

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Re: Naomi main board differences - HOTD2

Post by Pete » December 28th, 2012, 2:32 pm

It will run on the plastic Naomi's but only on the early revisions as they had extra GFX chips that were later removed on the newer boards.

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Re: Naomi main board differences - HOTD2

Post by Paladin » December 28th, 2012, 4:32 pm

Thanks for the reply!
I haven't seen any pictures showing the differences. It would be nice to have a visual reference showing the area of the board to look at.

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Re: Naomi main board differences - HOTD2

Post by andygeezer » December 28th, 2012, 5:01 pm

Just look for Naomi 1 with sanace fan.
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Re: Naomi main board differences - HOTD2

Post by Paladin » December 28th, 2012, 6:25 pm

So can I run all later Naomi games on an early mobo? Are there any other games that are locked to one type of board?

Somehow I knew Andy would have an answer!

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Re: Naomi main board differences - HOTD2

Post by andygeezer » December 28th, 2012, 8:29 pm

Paladin wrote:So can I run all later Naomi games on an early mobo? Are there any other games that are locked to one type of board?

Somehow I knew Andy would have an answer!
Early mobo does all. Its the original made in japan job. Like most japan game pcbs the first rev is japan made then later ones are generally cheaper made and normally made in china.
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Re: Naomi main board differences - HOTD2

Post by SuperMenteur » December 28th, 2012, 8:31 pm

What about Naomi 2 then ?

Does it run the "1st gen" games in compatibility mode ?

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Re: Naomi main board differences - HOTD2

Post by Paladin » May 16th, 2013, 8:06 pm

Update:
A friend helped me out with dual modding an early Naomi and it works as expected. I have a switch installed on the side of the Naomi and can switch between the latest Japanese bios and the HOTD2 specific bios. So flip a switch and swap the HOTD2 cart for a net dimm and I can run all gun games on one mainboard. One slight downside is that the text in the games is Japanese but the voice acting is still in English, so I think it's OK.

Now I just have to get the guts to cut holes in my nice monitor bezel for LED sensors.

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Re: Naomi main board differences - HOTD2

Post by Flyingfistofbudha » May 16th, 2019, 7:00 am

I have an early hotd2 mono
And I put multi bios in it last night
And it didn’t play snk ca capcom

I will try with net dim tonight

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