NES to 7800 controller mod help.

[GregadetH]

Hi all,

 

I've been on the good ol' interwebs trying to learn how to mod an NES controller for use with a 7800. I find plenty of "Lookey what I did!" vids but no actual tutorials. From what I gather, it's a simple matter of using a Genesis controller cable, cutting tracks and adding resistors. Has anyone here done this recently? If so, is there an online tutorial for it? And, am I dumb as a box of rocks for not being able to find this info anywhere? Don't answer that last question.

 

Thanks!

 

Greg

[GregadetH]

Bump.

 

Here's a brand new vid that somewhat explains the mod. I kind of understand the resistors, but my main question is which wires go where?

Edited March 11, 2010 by GregadetH

[jaybird3rd]

I've never modified an NES controller, but I've built other custom controllers for the 7800, so I'm very familiar with the wiring scheme. It was a simple but clever way of getting two unique buttons onto the ProLine controllers without sacrificing backward-compatibility with older controllers and games. The 7800 FAQ has a wiring diagram, but it might make the job look a lot more difficult than it is.

 

Basically, the wires from both 7800 action buttons are split to two inputs in the joystick cable. One of these inputs is the 2600 action button (shared by both buttons), for backward-compatibility with 2600 games. The other input goes to either the left or right paddle input (one connected to each button), and also to a 620-ohm resistor tied to ground. So, if a 7800 game uses two-button mode, it listens for input from the paddle lines, and if it does not (or if it's a 2600 game), it listens for input from the 2600 action button line.

 

The NES controller uses a different interface, so if you cut all the traces going to the chip inside the controller and wire directly to the traces for the buttons and D-pad, you should be able to make it compatible with the 7800. However, you won't be able to use the START or SELECT buttons, since the 7800 joystick interface doesn't provide enough unique inputs.

[GregadetH]

I've never modified an NES controller, but I've built other custom controllers for the 7800, so I'm very familiar with the wiring scheme. It was a simple but clever way of getting two unique buttons onto the ProLine controllers without sacrificing backward-compatibility with older controllers and games. The 7800 FAQ has a wiring diagram, but it might make the job look a lot more difficult than it is.

 

Basically, the wires from both 7800 action buttons are split to two inputs in the joystick cable. One of these inputs is the 2600 action button (shared by both buttons), for backward-compatibility with 2600 games. The other input goes to either the left or right paddle input (one connected to each button), and also to a 620-ohm resistor tied to ground. So, if a 7800 game uses two-button mode, it listens for input from the paddle lines, and if it does not (or if it's a 2600 game), it listens for input from the 2600 action button line.

 

The NES controller uses a different interface, so if you cut all the traces going to the chip inside the controller and wire directly to the traces for the buttons and D-pad, you should be able to make it compatible with the 7800. However, you won't be able to use the START or SELECT buttons, since the 7800 joystick interface doesn't provide enough unique inputs.

 

Thanks for the insight Jay. I thought I'd blow my kids mind one day by plugging an NES controller into the 7800. He's already mesmerized by the fact that you can use Sega controllers on the 2600.

[unhuman]

I hacked up NES advantage joysticks to Atari 7800. There's lots of space inside for the modifications

[GregadetH]

I hacked up NES advantage joysticks to Atari 7800

 

Blasphemy!

[thomas3120]

Bump.

 

Here's a brand new vid that somewhat explains the mod. I kind of understand the resistors, but my main question is which wires go where?

 

Hi Greg,

That's a video I put up hehe

I don't have a layout of the finished NES to 7800 wiring. But I did sketch out the wiring on the 7800 proline. When you look at the proline wiring, it does help when wiring up the NES controller.

Let me know if you want the sketch of the proline one.

 

Thomas

[GregadetH]

Bump.

 

Here's a brand new vid that somewhat explains the mod. I kind of understand the resistors, but my main question is which wires go where?

 

Hi Greg,

That's a video I put up hehe

I don't have a layout of the finished NES to 7800 wiring. But I did sketch out the wiring on the 7800 proline. When you look at the proline wiring, it does help when wiring up the NES controller.

Let me know if you want the sketch of the proline one.

 

Thomas

 

 

That would be awesome, sir! PM sent!