The PSIO development cartridge, that I had preordered in June 2017, finally arrived this month. The whole package is very well made and looks almost like a genuine Sony PlayStation peripheral. The cartridge requires a modification before use, the PSIO switch board installation. The switch board detects the presence of the cartridge and switches the signals from the ODD to the parallel port.
![PSIO package](https://retrostuff.org/wp-content/uploads/2018/09/psio_01-1017x1024.jpg)
![PSIO package](https://retrostuff.org/wp-content/uploads/2018/09/psio_02-1024x1008.jpg)
The package contains the PSIO cartridge, a quick start guide, the switch board, some wire and a sticker.
![PSIO package](https://retrostuff.org/wp-content/uploads/2018/09/psio_03-1024x622.jpg)
![PSIO package](https://retrostuff.org/wp-content/uploads/2018/09/psio_04-1024x775.jpg)
I’m going to install the switch board into my SCPH-5552 PlayStation that I bought years ago with a custom blue case.
![PlayStation SCPH-5552](https://retrostuff.org/wp-content/uploads/2018/09/psio_05-1024x700.jpg)
Installation instructions can be downloaded from the PSIO downloads page. There are instructions for 5 different mainboard revisions. The SCPH-5552 model has the PU-18 mainboard built-in, according to this list. Let’s open it up and check if this is true – you never know when dealing with a unit that has been put into a custom case.
Disassembly
![Upper case removed](https://retrostuff.org/wp-content/uploads/2018/09/psio_06-1024x724.jpg)
![ODD assembly removed](https://retrostuff.org/wp-content/uploads/2018/09/psio_07-1024x738.jpg)
![Metal case removed](https://retrostuff.org/wp-content/uploads/2018/09/psio_08-1024x715.jpg)
Yes, it’s really a PU-18 mainboard:
![PU-18 mainboard](https://retrostuff.org/wp-content/uploads/2018/09/psio_09-1024x681.jpg)
On the bottom side of the PCB there is a weird old modchip installation.
![PU-18 mainboard with modchip](https://retrostuff.org/wp-content/uploads/2018/09/psio_10-1024x766.jpg)
Installation
I covered the modchip with some tape for now, as it worked flawlessly so far, and went right for the switch board installation.
![PSIO switch board installation](https://retrostuff.org/wp-content/uploads/2018/09/psio_11-1024x733.jpg)
The installation manual warns about running wires over the ground contacts (circled), well, the same goes for the Kapton tape.
![PSIO switch board installation](https://retrostuff.org/wp-content/uploads/2018/09/psio_12-1024x758.jpg)
Before reassembling the console I tested the installation with the PSIO cartridge plugged in. It worked on the first attempt.
Some final touches: freeing the ground contacts and tidying up the modchip wiring with the leftover wire.
![Ground contacts freed](https://retrostuff.org/wp-content/uploads/2018/09/psio_13-1024x685.jpg)
![Modchip wiring fixed](https://retrostuff.org/wp-content/uploads/2018/09/psio_14-1024x760.jpg)
Ready to play!
![PSIO ready to play](https://retrostuff.org/wp-content/uploads/2018/09/psio_15-924x1024.jpg)