The PU-7 was the very first PlayStation 1 board that was released. It is found on all Japanese SCPH-1000’s, along with some SCPH-1001’s, SCPH-1002’s, SCPH-3000’s, and SCPH-3500’s.

This board is unique because it has the pins for S-Video video output along with the RCA video output ports. The S-Video port was only available on the Japanese SCPH-1000, but the pins are still on other systems with the PU-7 board.

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

PU-7 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-7.

All of the points being soldered to are pretty straightforward pads. They are all located on the bottom side of the board. The PsNee is a great chip for the PU-7 because it supports anti-modchip games. The Mayumi V4 isn’t compatible with the PU-7 at all, and the MM3 doesn’t support stealth mode with the PU-7.

Installation tips

Here are some tips I have for you when you are soldering your chip into the PU-7.

Cut your wires to be as short and direct as possible.
You don’t need to connect pins one and two of the ATtinyX5 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.
Try to position your chip towards the middle of where all the wires need to go, to minimize wire length.