PSX pad -> RetroDuo

[realyst]

Hi all, I touched this a bit using some thread necromancy here, but I'm going to provide some more details about my conundrum here since it primarily affects a NES mod.

Basically, it goes like this: I'm creating a hybrid console-in-a-box containing PS2, NES, SNES and PC components. The goal was to h ave them share a common controller: PSX dualshocks.

the PSX can control the PC part easy enough by modding a PSX->USB adapter. It can control the SNES portion using a PSX->SNES adapter from tototek

Now, the only thing supposedly stopping a SNES controller from controlling a NES is two flipped wires.

I plug in the PSX->SNES adapter to a RetroDuo console, the SNES portion works fine, the NES side flips out as if a number of buttons are stuck(start being one and at least one button, possibly 'A', though hard to tell). Thinking this was a quirk in the way the RetroDuo handles the NES control, I directly wired a standard NES controller wire to the PSX->SNES adapter and plugged it into an actual Mattel-manufactured gray box front loading NES. It did the same.

So, while supposedly the only thing separating a NES pad from a SNES pad is two flipped wires, the PSX->SNES adapter is managing to properly control SNES input while simultaneously breaking NES input.

I'm a solder-by-numbers guy. I can hold a soldering iron quite well, but much of the theory behind that which I'm soldering escapes me. I'm hoping to draw on any electronics or electrical engineering expertise I can from this forum in helping to identify what's going on and whether it's something that can be fixed.

Any help would be greatly appreciated.