Sega Saturn 3 region mod switch

Started by King of Dirt, July 17, 2017, 09:32:29 AM

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King of Dirt

So I'm a bit late to the party, but I've been doing an inventory of my older consoles and the various mods I would like to perform on them to get everything working to my satisfaction. One of these is installing a region switch in my Sega Saturn. I've already installed a mod chip in it a long, long time ago, but I would like to have a switch to jump between regions for the various Japanese games I own (instead of using the ST Key cart to play them).

I was reading up on the theory behind the mod and installing the actual mod, and it seems pretty straightforward for two regions (USA and JPN, for instance). I've worked up two diagrams (thanks, Paint!) that I have attached to this post.

So I guess I'm wondering if the 3P3T switch wiring for the 3 region mod I've outlined is correct or if it would work at all. I've seen the mods that use a three position switch and a hex inverter chip to switch between the three regions, but I'm not entirely clear if that's necessary or just another way of performing the mod. I'm working under the assumption that I can connect the common point pads from each jumper pair to more than one circuit on the switch; the way I have it set up, it would be necessary to set the Europe mode on the 3P3T switch. And that would leave an extra +5V connection on the Japan mode, but I guess if it's not bridged to anything it shouldn't hurt, right?

If anyone could take a look at the wiring diagrams I've worked up for the switches and give me an idea if I'm on the right track or not, well, that would be a huge help!



I've theorized that a 3p3t switch could work to get all three regions on one switch with no additional logic. But, none of those switches had the correct layout, they all used something else that made it impossible.

But today I never bother with region switches; I just pop in a region free bios. No switching, no drilling, everything works automatically.


Freakin awesome! I love Daytona USA because the racing is fun and the soundtrack is addicting! Virtua Cop is fun. Virtue Fighter 2 is fun!

Thank you so much, everything plays perfectly. Now I can have the great memories of my brother's playing these games.


The beauty of Lawrence keeping this place going all these years.  Gaming technology knowledge repositories are the best :))
I design PCBs for retro game systems :)