# PU\-20 PsNee modchip installation diagram \- William Quade

Canonical: <https://quade.co/ps1-modchip-guide/psnee/pu-20/>
Language: `en-US`

![PU\-20 PsNee installation diagram](https://quade.co/wp-content/uploads/2018/11/pu-20.jpg)

This board was used exclusively with the SCPH\-7000 series of consoles\.

For more information about [PsNee chips click here](https://quade.co/ps1-modchip-guide/psnee/) , for more information about [PS1 modchips click here](https://quade.co/ps1-modchip-guide/) \.

# PU\-20 PsNee modchip installation diagram

[![PsNee ATtiny45 pinout](https://quade.co/wp-content/uploads/2018/11/psnee-attiny45-1024x705.jpg)](https://quade.co/wp-content/uploads/2018/11/psnee-attiny45.jpg)

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\-20 PsNee installation diagram](https://quade.co/wp-content/uploads/2018/11/pu-20-1024x968.jpg)](https://quade.co/wp-content/uploads/2018/11/pu-20.jpg)

Above is the installation diagram for the PU\-20\. Just match each colored pin label in the diagram with any matching colored point on the board\. There is a second image of the chip in the diagram showing a good place to position the chip\.

# Installation tips

Here are some tips I have for you when you are soldering your chip into the PU\-20\.

- **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\.
- The DATA pin can be trickier to solder, make sure you don’t use too much solder or you risk bridging pins on the chip\.

# 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\-20 PsNee example installation](https://quade.co/wp-content/uploads/2018/11/IMG_20181123_222502-1024x768.jpg)](https://quade.co/wp-content/uploads/2018/11/IMG_20181123_222502.jpg)

This is an example of an installation I did in a PU\-20 using a socket\. Using the socket allows me to test chips, and test new PsNee code\. Note that the chip is a little too tall and prevents the top metal shield from going on all the way\.

4 Comments

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![JayBee](https://secure.gravatar.com/avatar/14ebc588b0daeb3f05bcd71a67b62083145ed9ea7b17269b73dcda760a68c131?s=64&d=mm&r=g)

JayBee

November 30, 2019 11:00 PM

Hello,
 Thanks so much for guide, it was very useful\!
 I did it successfully on my PS1 PU\-20 😉

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![HAA](https://secure.gravatar.com/avatar/14dcf1b54389e2b4c1d1691b27cd8fc2404f0eb8d960bbed7d939a85dcd372c2?s=64&d=mm&r=g)

HAA

June 13, 2020 2:50 AM

will it work with an Arduino nano

Last edited 6 years ago by HAA

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[![William Quade](https://secure.gravatar.com/avatar/14ac9361c0296cbe4c2282fc8bdbd92bd0f1f946ca84939cc222c68e865637e5?s=64&d=mm&r=g)](https://quade.co/)

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[William Quade](https://quade.co/)

June 13, 2020 4:54 PM

Reply to [HAA](#comment-4239)

It should\.

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![Alexis](https://secure.gravatar.com/avatar/7000e4b367d3370a4ca1902527f9591e0f6da1e39ace60672b9f1ac28519d5d0?s=64&d=mm&r=g)

Alexis

July 25, 2020 1:26 AM

Another success with this guide\. If you put the chip down near the cluster of testpoints [like this](https://i.ibb.co/NrdZWfg/signal-2020-07-24-171525.jpg) , it fits through a convenient cutout in the shield even with a socket\. Try not to mess with nearby RV703 though as it’s adjustable and will throw analog circuitry out of alignment if you turn it…

0