HOWTO: Modding a Genesis/Mega Drive 6 button pad for use with SF2 and others

[TheRogue]

Ok everyone, I thought I would do everyone a service here.  Finding the X68000-to-SNES/MD controller adapter is next to impossible, and so is playing SF2/Fatal Fury with a regular 2 button pad. So, brought to you for the very first time ever (at least to my knowledge, it's probably been done in the Japanese community many times before, but not that I've seen) a simple, 5 minute mod to allow the ubiquitous Genesis/MD pad to function as a 6 button X68k pad.  Pass it around, spread it around the web all you want. I'm going to add it to the GameSX wiki in a minute too.   This mod can be attempted by anyone with even the most minimal of soldering skills.  It requires 3 wires to be cut, crossed, and re-soldered. That's it, that's all.

Step 1: Open up your 6 button Genesis/MD controller and expose the printed circuit board

Step 2: Locate the small white molex connector that connects the controller cable to the board
NOTE: In every 6 button controller I have ever opened, the wire colors have always been the same. In case yours are different however, the wire number takes precedent over the color. For example, if I asked you to cut the orange wire (#5 in the photo,) yet your #5 wire was green and your #7 was orange, you should cut the #5 wire anyway.



Step 3:  Cut the black (#1), grey (#7), and white (#9) wires directly in the middle, so an equal length remains on both sides. I will now refer to the half of the wire connected to the white connector as the "controller side" and the half of the wire connected to the cable as the "cable side".

Step 4: Re-connect the wires in the following way:
NOTE: The copper wire inside the genesis controllers is of very poor quality and breaks easily, so I recommend wrapping each solder joint liberally with electrical tape immediately after making the join or the wire is apt to snap.

Cable side       -   Controller side
Black (#1)      -     Gray (#7)
Gray (#7)      -     White (#9)
White (#9)      -      Black (#1)

Step 5: Make sure that all your solder joints are insulated, then close the controller up. You're done! You have a pad that works with the Fatal Fury games as well as the Street Fighter games. A lot easier then looking for one of those pesky adapters, isn't it?

[Daimakaimura]

Nice work mate. Are you able to find or create a mod for using the XE-1 pro PC Engine (or Famicom) joystick on the X68000? Since it's difficoult to find the official MSX/x68000 XE-1 pro, it maybe useful an appropriate guide.

[TheRogue]

That would be very easy indeed. You would just have to disconnect the multiplexing circuit and connect the joystick and buttons directly to the appropriate pins. If you need the pinouts or more detailed instructions just PM me or email me at conrad (dot) russo (at) gmail (dot) com and I will walk you through it.

[papa_november]

Wouldn't it be better to make an adaptor?

[TheRogue]

Yes you could also do that, however I wrote this guide for people who are not hardware-savvy and would like a quick fix to play their games as opposed to going through the time to buy the housing and connectors to make an adapter. If anyone needs the info to make an adapter I can post that too.

[papa_november]

It doesn't work. I've checked and rechecked it. The game will think some other button plus up or down is being pressed at the same time that either up or down are pressed.

EDIT: It works in port 2 but not port 1. This is bad, very very bad.

[TheRogue]

I've used it on 2 separate controllers. (A regular 6 button pad and a capcom fight stick for megadrive) You did something wrong. I will open up the controllers and take pictures, as well as video of me using them if you don't believe me.

EDIT: If you try to use it for regular 2 button games it won't work. It only works for the games requiring 3 or more buttons. I should have included that as a caveat in my original post.

[Magic Knight]

EDIT: If you try to use it for regular 2 button games it won't work. It only works for the games requiring 3 or more buttons. I should have included that as a caveat in my original post.

That sounds like what happens on the PC-Engine, using a six-button controller (set to use six buttons) on games expecting two buttons makes the games go funky, due to how the scanning routine works.

[papa_november]

I know 6-button controllers don't work in 2-button games. I tried the pad with SF2CE and got the results mentioned earlier. At this point I don't think anything's wrong with the controllers or the adaptor, as the controller works in port 2 as a 6-button controller.

Rather, I'm beginning to suspect something's wrong with my machine, as the exact same controller does not work in port 1 with the exact same game.

I'm going to have to replace the 8255 IC and hope the problem goes away.

[TheRogue]

I apologize to you papa_november, I thought you were saying this mod was very bad, not that the results were bad news for you.  Sorry man, I hope you get your X68000 fixed up!

[emerald danjon]

i made this stick for my x68000 the first model CZ-600C and i broke the controlers joystick player one or some resistor...direction down is always push in this computer...,now the stick works great in x68000,amiga 500,megadrive...but i pay a high price,your mod is great and with your explanation looks easy thank you its no cool play SFII with 2 buttons...

stick:http://www.facebook.com/photo.php?pid=30739548&o=all&op=1&view=all&subj=26935841366&aid=-1&id=1414812720&oid=26935841366#/photo.php?pid=30739548&o=all&op=1&view=all&subj=26935841366&aid=-1&id=1414812720&oid=26935841366&fbid=1223888083396

note:no one pc engine was damaged in this experiment"already dead before..."

[papa_november]

I've managed to both fix my X68000 and make a converter. 6-button pads work perfectly now.

[TheRogue]

Papa, what was the issue with your machine? How did you manage to fix it?

[papa_november]

For some reason the 8255 chip, which controls the gameports and parallel port, got damaged just enough so that 6-button controllers wouldn't work but everything else worked fine. I ordered another one, swapped it in and 6-button controllers started working again.

[emerald danjon]

nec 8255 controls Printer and joystick ports...is a commom chip?is easy to find i think in my sharp x68000 CZ-600C is damaged too.

[papa_november]

It is ultra-common. Used in far more computers/peripherals than I can name.

I'm not sure if the X68000 requires a specific variant of it, but even the variant it ships with is easy to find.

[genocho]

Hi, thanks for this great mod.

I want to make it but without modifying the internals of my 6 button genesis pad.

The question is, how can I use this modded pad to play 2 button games or games like kharnov that needs megadrive adaptor to use 3 button ?

You have the schematics for make a 6 button - 2 button switch and can use 6 button pad with all the games of x68000 ?

Thanks in advance,

Genocho.

[saxabar]

There is a 2-6 buttons adapter for genesis pad included in some Street Fighter 2 x68000 games