PU-8 PsNee modchip installation diagram

This was one of the earlier PlayStation 1 board designs that included RCA composite video output ports on the back. Most SCPH-1001’s here in the United States had this board inside.

Additionally many Japanese systems had this board including many SCPH-3000, SCPH-3500, and SCPH-5000’s.

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

PU-8 PsNee modchip installation diagram

PsNee ATtiny45 pinout

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

PU-8 PsNee installation diagram

PU-8 PsNee installation diagram

Above are two installation diagrams for two different versions of the PU-8. The easiest way to know which you have is to look at the size of the Mechacon controller chip (next to SUBQ and SCLK/SQCK). If it’s large, use the bottom diagram, if it’s small, use the top diagram.

Installation tips

Here are some tips I have for you when you are soldering your chip into the PU-8.

  • 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.

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)
  2. Nall Wolf

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.

  • William Quade (me)

PU-8 PsNee example installation

Ignore the larger board in the diagram, it’s a PSIO switchboard.

PU-8 PsNee example installation

PU-8 PsNee example installation

  • Nall Wolf

PU-8 PsNee example installation

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Nall Wolf
Nall Wolf
January 2, 2019 2:10 PM

I’ve just successfully installed a PSNee in my SCPH-1001, but neither of the diagrams were correct for my PU-8 board. I ended up having to compare the two diagrams and make my best guess at where the points were, especially for DATA, GATE_WFCK, and SCLK. Here’s a pic of my finished install, hopefully it helps anyone else with this specific board: https://imgur.com/a/glRIOHV

You may edit and use this image as an example if you want.

Cameron Tinker
Cameron Tinker
September 10, 2019 9:05 AM

Hey William, thanks for the PSNee modchip. I successfully installed mine using the same wiring configuration as Nall Wolf’s.comment image

Talon Overstreet
Talon Overstreet
October 28, 2019 9:58 PM

Successfully chipped my SCPH-1001. Kind of used both images to do it and ended up taking ground off of the pin on the end of that RAM (I think) chip because it’s pretty close to where I put the PSNee and I think it looks pretty clean. Here’s the finished product and my own guide I made: https://imgur.com/a/HP45Mfw. Feel free to post them here so others can see.

Emil Gora
Emil Gora
October 29, 2019 6:31 PM

Thanks for the chip! I had the same variant board with the small controller.

March 13, 2020 6:22 PM

Just got my PSNee i ordered in the mail today, and followed your install diagram in the first pic, as the motherboard matched mine… well it seems my system is dead now… Would like to know how it went wrong as I had an mm3 in there previously which went fine. the disc wouldn’t spin, then the video cut out and i get nothing. the system does power on though. so I don’t think its the fuse. after removing the chip i have the same result now. Any idea what went on the ps1 motherboard? the system is essentially dead.

March 13, 2020 7:35 PM
Reply to  William Quade

Thanks for the quick reply, I’ll see if anything looks off. I think what might have happened was I wrapped the chip in tape and a couple of legs poked through and might have shorted something. I’m using some heat shrink instead now to hopefully avoid another issue.