Modding Genesis controllers to 7800 controllers

[+HammR25]

Ok I was looking into modding my genesis controllers so that they'd work with my 7800. Of course as I searched I found it already works fine as a 2600 controller. I was just trying to figure out how to mod the controller to use the second button when necessary.

 

I read through all the stuff I could find on the net and honestly the electrical stuff makes no sense to me. Since Genesis controllers are so cheap right now I just went ahead and bought 6 of them brand new on eBay for $17 shipped. I figured I'd get extras in case I screwed up a few of them.

 

I went ahead and opened one of my genesis controllers and found the following stuff on the back of it.

 

 

 

Shouldn't I just be able to change around some of those pinouts to get the controller to work as a 7800 controller and if so does anybody know which one before I start going trial and error.

 

Otherwise I suppose I'll need to cut open the other end of the controller to see which wire ends up where. I was just hoping to avoid doing the same thing for a 7800 controller although maybe I can learn how to read the pinout stuff that's already on the net.

[jaybird3rd]

7800 controllers are wired in an interesting way to get the two-button configuration working in a way that was also backward-compatible with single-button 2600/7800 games. Each of the buttons is actually connected to two inputs in the joystick connector: they both share the 2600 trigger wire (so that either one of them will work with 2600 and single-button 7800 games) and they are also connected independently to the two paddle input wires (which are then read by two-button 7800 games).

 

To get the Genesis controllers to work in the same way, it will be necessary to replicate this wiring scheme. It isn't as bad as you might be thinking, but it is a bit more involved than simply changing the pinout. There is a set of pinouts in the 7800 FAQ which might be helpful, and I'm sure one of us can give you some additional help (I've built many 7800 controllers out of modified Space Invaders TV-games). If you'd prefer to build an adapter instead of modifying the controllers, there is a link in the FAQ that will take you to another site with a list of instructions on how to do this. I've never tried this myself, though, and to me it looks like a lot more work.

 

EDIT: One place to start would be to let us know what type of controllers you have. Are they three-button or six-button controllers from Sega, or are they from a third party? It would also be helpful to find out which wire goes to which pin in the connector before you start. After a quick search, I found the following information on this site:

 

Looking straight at the plug on the front of the Genesis the numbers are:

1 2 3 4 5
 6 7 8 9

(For those of you who buy a joystick cable from radio shack the pin #'s to wire colors are as follows: 1-white 2-blue 3-green 4-brown 5-yellow 6-orange 7-red 8-black 9-gray).

 

The pins in the cable will be a mirror image of the diagram, of course. I would strongly recommend that you confirm this information with your own cables; the website may be incorrect, or the colors might be different if the controllers you have are from a third party. There's a much easier way of doing this than cutting open the cable. If you don't have a continuity tester, you can use something like the LED and battery inside one of those little keychain lights. Leave one leg of the LED connected to the battery and connect the other leg to a loose wire. Connect another wire to the battery (the one that the other leg was connected to) and touch the two wires together to make sure the light goes on. These two wires will then become your "probes" for testing the cable: insert one of the wires into one of the pins and use the other one to test each of the wires at the other end (the white connector inside the controller) until the light comes on. Make note of which wire connected to which pin, and test all of the remaining pins in the same way. If you have a continuity tester, you can use that instead.

Edited January 16, 2006 by jaybird3rd

[+HammR25]

My one not butchered controller is a 6 button Sega controller. I'm not sure about the other 6. They look like they were made by Sega though. They're also 6 button. I bought them on eBay today. I'll rip one of those apart to see what the colors and pinouts are there to be safewhen I get them.

 

According to that diagram it's as follows:

 

1 Green

2 Yellow

3 Orange

4 Red

5 Brown

6 White

7 Black

8 Gray

9 Blue

 

Personally I think that diagram has the numbering backwards because Deathskull Laboratories has them opposite of that and both the Atari and Sega pinouts have pinout 8 as black ground in that configuration and my controller matches that.

 

Going by Deathskull:

 

1. Brown

2. Red

3. Orange

4. Yellow

5. Green

6. Blue

7. Gray

8. Black

9. White

 

I was going to play with the pinouts on the controller but didn't feel like trying to move them and end up breaking something because I didn't know how to properly release them.

 

Thanks for your help.

Edited January 16, 2006 by HammR25

[jaybird3rd]

Yes, the controller diagram I quoted was a diagram of the connector on the console side. The controller side would be the opposite of that; the wires on the lefthand side of the connector will plug into the righthand side of the plug on the console. I don't know how easy it will be to actually move the pins around (or even to cut open the connector to see them) because Sega and Atari plugs were all molded into one piece.

[+HammR25]

In the back of the Sega controller it looks like it should be easy to move the pins. I think that setup is designed to have things moved around........but yeah changing the pin-outs in the connector would be impossible. I had to destroy the connector just to see what the colors are.

 

Maybe you can tell what I'm talking about in that terrible webcam pic I put in the first post. I'd take a real pic but I left my digital camera at my brother's house at Christmas and haven't gotten it back yet.

Edited January 16, 2006 by HammR25

[+HammR25]

Maybe this pic will show what I'm talking about a little better. This is inside the actual controller. These go straight down the cord to the connector.

 

[jaybird3rd]

Ah, I see; I thought you were talking about the plug on the end of the cable. You'll probably only have to pull out or move the wires related to the buttons; if the controller works for 2600 games as-is, you can leave the directionals intact.

[bjk7382]

Why not just use the NES => 7800 conversion already typed up on the net by Graham Percy?

 

It is what I use, although prices of nes controllers are going up.

 

I have taken 35 nes controllers out of circulation and made them atari controllers.

Edited January 16, 2006 by bjk7382

[+HammR25]

I looked at the NES stuff. It looked like more trouble than it was worth since I'd have to find some Atari controllers as well.

 

Anyway with the Genesis controller it looks like I need to change out pinout 5 to 7 then 9 to 5 and 6 needs to somehow also go to 9?

[bjk7382]

I looked at the NES stuff.  It looked like more trouble than it was worth since I'd have to find some Atari controllers as well.

1001650[/snapback]

 

No atari controllers needed, you just buy some cheap genesis extensions off of ebay as well as some 620 ohm resistors for 2.00, and you are good to go

[Shawn]

Why not just use the NES => 7800 conversion already typed up on the net by Graham Percy?

 

It is what I use, although prices of nes controllers are going up.

 

I have taken 35 nes controllers out of circulation and made them atari controllers.

1001414[/snapback]

 

 

You did the world a favor.

[Almost Rice]

No atari controllers needed, you just buy some cheap genesis extensions off of ebay as well as some 620 ohm resistors for 2.00, and you are good to go

1001728[/snapback]

 

I guess I will have to modify the instructions for a 500xj I picked up. It was for the NES.

[keilbaca]

Why not just use the NES => 7800 conversion already typed up on the net by Graham Percy?

 

It is what I use, although prices of nes controllers are going up.

 

I have taken 35 nes controllers out of circulation and made them atari controllers.

1001414[/snapback]

 

I personally like the genesis controller better than the NES controller, so it would make a better 7800 controller.

[jaybird3rd]

I looked at the NES stuff.  It looked like more trouble than it was worth since I'd have to find some Atari controllers as well.

 

Anyway with the Genesis controller it looks like I need to change out pinout 5 to 7 then  9 to 5  and 6 needs to somehow also go to 9?

1001650[/snapback]

You might get the directionals working that way, but you'll likely have to cut some traces and add a few jumpers to get the buttons working properly in two-button 7800 mode (unless the Genesis controller happens to have the wiring and two 680-ohm resistors in just the right places, which I doubt).

[jferio]

I did one of these fairly recently, when I was dogsitting for a friend and had access to his 7800 for testing.

 

I've found that there are at least *two* forms of the three button Genesis pad out there. One, the one I modified, has older 'conventional' electronics inside it that were easy to remove and rewire.

 

The second type, one of which provided the replacement cable for the damaged one that the controller I rewired came with, has surface mount electronics.

 

The first type is far easier to modify. I found I had to cut the ground traces on the buttons to do what I wanted, since that's where I wired the power to. The original positive feed side became the ground and 'other' input of the buttons.

 

Once I got it to work, I was exceedingly happy with it. It makes an alternative for the ProLine stick, for those friends who can't use the ProLine because of it's design. I've never had problems with the ProLine myself, but it never hurts to have another 7800 compatible controller.

 

I'd post pictures of the hackery, but I would need to borrow a digital camera to do it.

[+HammR25]

When I first was looking into this the stuff at http://www94.pair.com/jsoper/7800_gen_adap.html looked daunting. Now that I think I've figured out what he did it doesnt' look nearly as bad. I'd just need to learn some soldering skills and find some of those parts. Option 1 looks the best.