Dual Modding 101

DarkSakul · October 11, 2020

The following thread is a work in progress.

Disclaimer
Please remember that It is the end user’s responsibility to see to and to carry out proper implementation their own repairs and modifications. Ultimately the end users hold responsibility for how they implement their own repairs.

So you want to mod your stick so it works with more than 1 console/ system and that means ether replacing the PCB (printed circuit board) or adding an additional PCB.
Were going to focus on the 2nd, adding a second PCB to the first of your stick or controller.

I am going to make a few assumptions before I continue, I am assuming the reader knows the following

Basic electrical wiring
Basic electrical theory
That you know how to solder
That you know how to wire up your stick without dual modding

I also recommend reading up on http://slagcoin.com/

The site is kind of dated now, but all the basics and fundamentals still holds true. It covers basic arcade stick wiring and prepping various controller PCBs for arcade stick use, as well as building arcade sticks.

Before we begin a quick quote from the Cthulhu PCB creator Toodles

Quote

Q: What are the golden rules?
A: The two golden rules of dual pcb mods:

All pcb’s must be common ground.

All pcb’s must be powered at all times.*

*The power going to the PCBs should only be coming from one console.

What we mean by common ground in this context?
All your buttons, joystick directions, and inputs share the same ground path, or all their grounds are tied together.
That if I get out a multimeter or continuity tester I can trace all the return voltages of each switch and input to a single ground trace/ground plane.
What is a ground plane, a it's just a really thick area of copper on the board attached to ground or GND.

How do I know my PCB is common ground or not?
We take the PCB out and test it with a Multimeter on continuity test mode, Diode test mode (and listen for the beeps) or if your multimeter is cheap or really old resistance mode (and you bee looking for zero ohms resistance but you can see the power going though). In a pinch of you lack a multimeter you can wire up a single circuit with a LED, a battery and some length of wire (google DIY continuity tester) .

You should get all your return or Gnd for each button contact and com/gnd on each switch going back to the same gnd.

Here is an example of a Common ground PCB, with the ground points and inputs labeled

Why all PCBs needed to be powered?
Good question. With all PCBs powered, you do not have stray signals going from one PCB to another creating erroneous or false inputs, nor are you getting any inputs lost or interfered with. Keeping power on all boards keep the board's encoder on Idle, and they don't send out false inputs.
But wouldn't that happen as the PCBs are plugged into the system?
No, as you do not want both PCBs plugged into their respective systems at the same time. If you are using an single RJ45 connector 9or another style connector) for system cables, you can only plug into one console at a time. It is not advisable to plug your stick into multiple consoles/systems.

What you are trying to create with a dual mod would perhaps resemble this

Here are two PCBs with both of their Inputs wired together in a terminal strip going to the buttons and joystick.
You don't have to follow this diagram to the letter, just illustrating how such a mod can be done.

Two PCBs Dual Modded with Both using USB

Items you need

1 common ground Controller PCB ( I would imagine this is already in your stick)
1 different common ground Controller PCB (as it make no sense to use 2 of the same PCB)
Wire
DPDT switch (double-pole, double-throw) or a device that can take the function of a DPDT switch
Your arcade controller/ Stick
Your electrical tools, soldering iron, pliers, wire strippers ect.

You are going to cut the data lines on the USB cable (the green and white wires) and connect them to the output on the DPDT. Then find and connects the dates line from both boards to the inputs. Just make sure you keep green and white in order, especially if you use 1 color of wire.

For our example We are going to have a PS3 PCB and a Xbox 360 PCB, but any USB based PCB would work (including multiboards like the MC Cthulhu).

You want to wire your DPDT switch like this

Edited October 11, 2020 by DarkSakul