This is my favorite version of the PlayStation 1. It’s in newer systems, so the lasers are more likely to still be in good condition, but the system still has both the serial and parallel ports on the back. This board was used primarily with the SCPH-7500 series of systems.

For more information about PsNee chips click here, for more information about PS1 modchips click here.

PU-22 PsNee modchip installation diagram

Arduino pinout:

• Pin VCC – VCC
• Pin GND – GND
• Pin 3 – Debug TX
• Pin 4 – BIOS A18
• Pin 5 – BIOS D2
• Pin 6 – SQCK
• Pin 7 – SUBQ
• Pin 8 – DATA
• Pin 9 – GATE_WFCK

Above is the diagram for the PU-22.

This diagram is fairly straightforward. Be careful when soldering to the capacitor that connects to VCC and GND. In particular, the GND point can easily be bridged to nearby pins/pads.

Installation tips

Here are some tips I have for you when you are soldering your chip into the PU-22.

• You don’t need to connect pins one and two of the ATtiny45 chip. Just desolder the wire.
• Use a multimeter to probe around for alternative VCC and GND points closer to where you position your chip for a cleaner installation.
• Placing the chip on top of the chip in between SUBQ, SQCK, GND, and VCC is a good spot.
• Watch out for solder splatter when you are desoldering the metal shield on top of the board. It isn’t necessary to put it back on, but I always do.

Diagram success rate

Here’s a list of people who have successfully modded their console with this diagram. Leave a comment and I’ll add you to the list.

1. William Quade (me)

Example installations

This section has photos of some successful installations which you can use to get a better understanding of how everything is wired and positioned.

• Nobody yet.