The mod detects button presses from inside the PlayStation 1 and will reset it whenever a defined button combination has been pressed.
For now the button combo is L2 + R2 + Select + Start for the digital an analog controllers and A + B + Trigger for the GUNCON.
Here's a little test to show that it works. Note that there was a 1 sec delay in the code as to not spam PuTTY.
[BBvideo=560,315]https://www.youtube.com/watch?v=dBLZW0fIh68[/BBvideo]
See my github page for the software (mplabx) and hardware (kicad): https://github.com/pyroesp/PlayStation-1-Reset-Mod
There's a video on the github page too if you want to see the proof of concept I made with an arduino nano.
Below is a board render out on KiCad. The actual board size is 14.5mm x 12mm, with 1.5mm diameter pads:


Back side is used to program the PIC microcontroller.
I've added both 1206 and 0805 resistor/capacitor, for those that don't feel comfortable hand soldering 0805.

* I need to add text on the silkscreen to differentiate the cap from the res.
The microcontroller is a PIC16F18325, ran at 32MHz internal oscillator at 3.5VDC provided by the PlayStation 1.
I'm looking for people who might be interested in this and would be willing to provide documentation (pictures/annotation is fine) on where the mod could be soldered on the different PlayStation 1 motherboards.
See also this issue I made on my github : https://github.com/pyroesp/PlayStation- ... d/issues/4
I have a PU-18 and iirc a PU-22 so I can make guide for those motherboards, but I don't have any of the other ones.
This evening I'll be sending the PCB files to JLCPCB, so I'm going to receive 10 boards in a couple of weeks.
For those that want to help, I can try to send those (populated or not, depending on shipping cost) to you.
pyroesp