Introduction: How to Modify a Genesis Model 3 to Play Japanese Games

About: I'm a web developer by trade. I'm a tad obsessed with video games, especially retro games and consoles.

I recently picked up a Genesis 3. If you haven't seen one, they're very small versions of the Genesis. I later found out that they can apparently play Japanese imports. The cartridge slot is even wide enough to accomodate the larger Japanese cartridges, unlike the original and second generation versions of the Genesis (you have to widen their slots with a dremel or file). So I picked up a copy of Phantasy Star II on eBay to give it a try.

It turns out that it's only partially true. It will supposedly play Japanese imports which do not have an internal region lockout. It appears that Phantasy Star II does have that lockout, because after the initial Sega copyright screen, it just gave me a black screen.

This was not a big deal. I don't know of any Japanese Mega Drive (the Genesis was called the Mega Drive outside the U.S., or rather, the Mega Drive was called the Genesis in the U.S.) games that I desperately want to play. Still, I thought it would be fun to try to get it working. And besides, Phantasy Star II cost me like $8, and that's enough to buy a decent sandwich. And I can't eat a Phantasy Star II cartridge. Believe me, I tried (note to self: try adding more cumin next time).

I gathered information on this mod from a number of places. Unfortunately, most of the instructions I've found have been pretty light on details. And since there are instructables for Genesis models 1 & 2, but not 3, I thought I'd condense what I found out here, accompanied by some pretty pictures.

So let's mod a Genesis 3!

Step 1: What You'll Need

You will need:
  • 1 Sega Genesis 3. Obviously.
  • 1 or more Japanese Mega Drive games. Again, obviously.
  • 1 Phillips head screwdriver.
  • Tweezers.
  • Soldering Iron. I used a 25W one. You don't want to use one that's too hot here.
  • Thin wire. I used IDE ribbon cable.
  • SPDT Switch. I didn't need one, which surprised me. I'll get to that later.

Step 2: Open the Console

There are four small screws on the bottom. Remove them.

Remove the top, noting that the power switch needs to line up with an internal switch. You may notice in the photo that I have some wires connecting the top to the bottom half of the console — a while back I installed an LED under the power switch.

There are several screws holding the RF shield on. Remove them, then remove the shield. You could probably throw the shield away, but I didn't.

Take a look at the motherboard. They produced 2 or more versions of the board. Mine appears to be a VA 2 model. Yours may not be. The procedure is probably basically the same across models, except that the solder points are in different spots. If yours is different from mine, check out these instructions, which are for a different motherboard model.

You can go further and remove the board from the bottom of the console case, but I did not. There's a grounding plate / RF shield attached to the bottom, and having plugged in a console that wasn't properly grounded before, I didn't want to take any chances.

Step 3: Remove the Jumper

Removing the jumper was the most difficult part for me. I was pretty sure I was going to destroy the console in the process, but (amazingly) I didn't.

The jumper we want to remove (remember, this is for the VA2 model) is near the cartridge port, on the side closest to the power and av jacks. It has "R22" just above it. See the image annotation for the exact location. This jumper is what puts the console in US mode (sort of).

I only had some lousy household tweezers. I need to get some of those nice angled ones made for this kind of thing. Anyway, I basically hacked at it. I'd grip the jumper with the tweezers, heat up one side of the jumper with my soldering iron, and try to pull it off.

I eventually got it off. Be patient and don't keep the soldering on the solder point too long. A couple seconds each time at most. Too long and you'll likely damage something.

I used an utility knife to carefully cut between the contact points to make sure there was still no contact. Test with a multimeter. 

Step 4: Do Some Testing

I'm not a world champion solderer. And I'm certainly not always comfortable with such small solder points. So I wanted to make sure this was going to work and that the points I was going to connect were the correct ones.

So I plugged the Genesis in and connected it to a TV. I popped Sonic 2 in, turned it on, and to my astonishment, it worked.

I was not expecting it to work. This was the U.S. version of it, and I thought I had just removed the jumper enabling that. Nevertheless, I tried again with the Phantasy Star II. It didn't work, as expected (I hadn't connected the proper points yet).

Then I turned it off again and connected the points at R24 with a length of wire (see image annotation). Just use some flexible breadboard wires or whatever. I stripped the ends off some AWG 22 solid-core cable.

I turned it on, and it worked! The Phantasy Star II title screen came up. Interestingly, when I removed the wire, it froze.

Then I thought I'd try something goofy. I put Sonic 2 in the slot, connect the points at R24 again with the wire and turned it on. The game came right up.

This is contrary to what I'd been led to believe. I was under the impression that to play U.S. games, the points at only R22 would need to be connected, and to play JP Mega Drive games, the points at only R24 would need to be. But for me, connecting just R24 points works for both U.S. and JP games.

UPDATE: After further experimentation using different models, it turns out that some older games don't do a region check and will happily play whether the console is configured for US or JP. Sonic 2 is one of them. I have several US games that will not play when configured for JP. One is "Pac-Man 2: The New Adventures". When I get around to installing the switch on this console, I will update this instructable with pics and further instructions, if necessary.

Step 5: Solder the Connections

UNPLUG THE CONSOLE. Don't solder anything to this thing while it's turned on. What are you, a lunatic?

If you don't get the same results I did, and you need one set connected for U.S. games and the other for JP, you can connect a SPDT switch to toggle between them. The solder points facing the front of the console appear to be connected (I didn't think to check with my multimeter), so either of those would be the middle connector in the switch, then the other two opposite solder points would each go to either of the remaining throws on the switch.

But again, I didn't have to do that. I just took a wire and soldered each end to the points on R24. Strip a small amount off each end of the cable and melt a little solder on them. Put one end on one of the solder spots and briefly press the soldering iron on them. It should only take a second. Repeat for the other one.

Plug it in and test.

I tested with PS II. It worked! I tested with Sonic 2. It worked! I put PS II back in, thinking I'd play it for a while before closing the console up. Then I realized that I can't read a word of Japanese. That fact kind of got lost in the excitement of getting the game to work.

Oh well, let's close it up.

Step 6: Finishing Up

To close it up, just reverse what you did earlier. Put the RF shield back on, screw it on, etc.

If you had to install a switch, you'll need to cut a hole and mount it before putting the console back together. There appear to be a couple good spots for it. Right on top of the console could work, or maybe somewhere behind the cartridge port. You should be able to epoxy or hot glue it in place.

Now play some Japanese Mega Drive games! Or stumble through them, if you don't speak or read Japanese, like me.

If I ever get my hands on a Genesis 3 with a different version of the motherboard, I'll definitely update this with pictures and instructions for it.