Switch Board

What is it and why do I need it?

The Switch Board switches required data lines and forwards them through to the PSIO cartridge. It does exactly as stated which is that it is just a switch. In no way shape or form is this a modchip. It does not bypass the system protection or allow booting of copied discs. It is completely invisible to the system and it causes no harm or effects to the hardware.

Exactly why is it required?

There are two signals that PSIO needs in order to function that are not present on the expansion port. These are the CS (Chip Select) and INT (Interrupt) lines from the CD controller. The job of the Switch Board is to basically forward these signals as well as connect them back to the CD-ROM drive when PSIO is unplugged (or if you boot a CD-ROM). In a nut shell, when PSIO is active, the internal CD-ROM controller is disabled and all accesses is redirected to the emulated CD-ROM controller in PSIO. All the hardware registers are still in the same place.

How do I identify my model so I know what to download?

When you disassemble your PlayStation, the mainboard will have a code marked "PU-xx" (where "xx" is your model number).

This model number is important to know so you can match it with a "Switch Board Installation Guide".

How hard is it to install the Switch Board?

If you have worked with surface mount components it is extremely easy to do. If you have not, then you may struggle as it's very fine based solder work. Depending on your PlayStation model, you will generally be required to cut at least three (3) traces on the mainboard. You will also be required to scratch the soldermask off of vias (tenting) with a knife and then solder to the vias.

Can I send you my mainboard so you can do it for me?

We no longer offer to customers the ability to send board to us (Cybdyn Systems), but we do have an option in our 'Store' where you can select from a list of installers to have your board sent to them to have it done for you.

What are the technical specifications of this circuit?

The Switch Board has a maximum input voltage of 3.3 Volts. Do not solder it to a 5.0 Volt rail in the PlayStation. Note that the newer Switch Boards from 2017 onwards (silk screened as "SB17" on the PCB) now contain a Schottky Diode which assists with protection against reverse polarity. This was done as a safety precaution since CMOS integrated circuits get extremely hot if the voltage rails are wired backwards. The diode we have in the new Switch Boards eliminates this risk entirely. Prior to the SB17 revision, we advise that you check that your ground and voltage rails are not backwards before powering on your PlayStation after you have installed a Switch Board.

Where can the installation documents be found?

In the 'Downloads' tab located under 'My Account' (click here).

Is the Switch Board open-source hardware?


Do you have a schematic of the Switch Board available?

Yes, and it can be found at the end of any 'Switch Board Installation Guide' document.

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