Sony PSIO User manual

1 PSIOSB08052016-PU7
PSIO
Switch Board Installation Guide
Revision 1.0
PlayStation Mainboard [PU-7]
PlayStation is a registered trademark of Sony Computer Entertainment Inc.
PlayStation is Copyright © 1994 Sony Computer Entertainment Inc.
PlayStation, , “DUAL SHOCK” and “PSone”are registered trademarks of Sony Computer Entertainment Inc. .
PSIO (PlayStation Input Output) is in no way affiliated with Sony Computer Entertainment Inc.
By running PSIO, you agree not to hold us responsible or made liable for any damage to your console.
The user of PSIO assumes full responsibility ensuring its use in accordance with local and federal laws. The software and hardware is
provided "as-is", without any express, implied warranty or guarantee.
“PSIO”is Copyright © 2010-2016 Cybdyn Systems. All Rights Reserved.

2 PSIOSB08052016-PU7
Introduction:
Before playing games from PSIO on your PlayStation 1, the Switch Board must be installed.
To install it, some fine soldering is required. This document is a guide on how to install it for your
[PU-7] PlayStation mainboard.
The Switch Board is included for free with each PSIO cartridge purchase.
If you require additional Switch Boards, they are available for purchase in the ‘Store’.
This guide is by no means intended for beginners in soldering or electronics.
We will NOT be held responsible for any damage to your PlayStation console, or PSIO cartridge.
By continuing with this installation document, you must be competent with a soldering iron and
know how to cut traces on mainboards.
Please check for updated versions of this manual at http://ps-io.com/switch_board.html.
To report any problems, please see http://ps-io.com/problem.html.
Index:
1-0: Switch Board:
[1-1: Information]
[1-2: Installation]
2-0: Specifications:
[1-1: Hardware]

3 PSIOSB08052016-PU7
1-0: Switch Board:
[1-1: Information]
The Switch Board is required in order for PSIO to work correctly. The reason behind it is that Sony
never provided direct access to the CD-ROM CPU on the Parallel I/O bus. In our case, access to the
CDDA and XA interrupt lines. What the Switch Board does is it actually switches the required data
lines and forwards them through to the PSIO cartridge. The Switch Board also allows PSIO to drive
the CD-ROM directly and give us complete control over it.
Keep in mind that the Switch Board is completely invisible to the PlayStation.
That means, when your PSIO cartridge is unplugged and not in use, your PlayStation returns back to
normal operation. The CD-ROM drive will work as it normally would, and you will also be able to
use Game Shark/Action Replay cartridges like normal.
If you have a Modchip installed in your PlayStation, the Switch Board and Modchip will work fine
side by side with each other. Remember, the Switch Board is invisible to the PlayStation.
[1-2: Installation]
First off, you will require some tools:
-Switch Board (included with your PSIO cartridge purchase),
-Kynar Wire (included with your PSIO cartridge purchase),
-Soldering Iron (use a good tip!),
-Solder (preferably flux cored 60/40),
-Flux (optional),
-10x Magnification Jewellers Microscope/Loop (optional),
-Phillips Screwdriver,
-A Multimeter (for Continuity Testing),
-A sharp ‘hobby’ knife (EG: X-Acto), and
-Scissors.
Let’s begin.
First off, you will need to disassemble your PlayStation 1. However, before you start to disassemble
your console, you must ensure that your PlayStation 1 is completely isolated and unplugged from
all connections, including most importantly, the main power cable (AC).
Ensure that you have taken out any CD-ROM’s in the drive and have put them away safely.
Once you have ensured your console is isolated and unplugged, turn it over, and unscrew all of the
screws on the back. Then, whilst holding the sides with two hands, flip the console over. You can
then lift off the top shell to expose the internal components.
The next step is to remove the CD-ROM assembly system. There are two cables that connect the
drive to the mainboard. One is a delicate ribbon cable, and the other is a pair of twisted core wire.
Both cables simply unplug by pulling on them, but be careful not to tear the ribbon cable.
Depending on your PlayStation model, each system disassembles differently from here on in, but
the next step is essentially removing the metal chassis.
Once you have removed all the screws from the steel chassis, it should now lift of freely, exposing
the bare mainboard.

4 PSIOSB08052016-PU7
Next, begin removing the rest of the screws holding the mainboard to the bottom half of the plastic case.
Keep in mind that when reassembling your console that the screws go back in a certain method as some
are left blank for the steel chassis to mount though.
Once you have the board out of the console, flip it over to show the bottom layer of the PCB (as seen in the
image below). Next, carefully peel off the double-sided tape on the back of the Switch Board, and adhere it
to the seen location marked in red below. Do not place it anywhere besides the specified area, and ensure
that you have the Switch Board orientated in the correct position before securing it. Ensure the Switch
Board is adhered well and it will not fall off and short itself against the steel/metal chassis that is housed
under the PlayStation mainboard.

5 PSIOSB08052016-PU7
The next stage is to cut a trace on the Parallel Port. It is known as Pin 5, and it is a Ground pin, but it must
be used instead for the Switch Boards “EN” (Enable) line.
Cut through the marked point in red to isolate Pin 5.
Solder Pin 5 to the “EN” line on the Switch Board.

6 PSIOSB08052016-PU7
The next step is to solder the “CD MECH INT”and “CD MECH CS”lines.
Note that there are no trace cuts in this photo.
You can see the points marked in yellow for where to solder.

7 PSIOSB08052016-PU7
The next two trace cuts are more difficult. They are known as the “CPU INT”and “CD MECH CS”lines
(marked in red). They might take you a while at first to locate on the mainboard, but take your time and
don’t rush.

8 PSIOSB08052016-PU7
Cut the ‘CPU CS’trace where the red line is placed.
The outlined areas marked in green are where you solder. However, the soldermask on the ‘CPU CS’ via
must be carefully scraped away to expose the copper. The ‘CPU INT’ has a pad conveniently placed and
does not require the soldermask to be scraped on its via.

9 PSIOSB08052016-PU7
The next two (2) pins to solder are pins 65 and 31 on the parallel port.
There are no trace cuts needed in this step.
Pin 65 goes to “PE” on the Switch Board.
Pin 31 goes to “PI” on the Switch Board.

10 PSIOSB08052016-PU7
Lastly, the power connections are required. The first one is the 3.3V (3V3) rail.

11 PSIOSB08052016-PU7
And secondly, the “Ground (Gnd)”connection.

12 PSIOSB08052016-PU7
Congratulations! You have successfully modified your PlayStation with a Switch Board.
This is what your installation should look like.

13 PSIOSB08052016-PU7
As a warning, we suggest that you check for shorts on the Ground (Gnd) and 3.3 Volt (Vcc) rails using your
Multi-meter (continuity tester). If you do not check and there is a short, you will blow a fuse on your
PlayStation mainboard, and it will be required to be replaced.
With that being said, you may now re-assemble your console and test CD-ROM loading without a PSIO
cartridge plugged in, and then testing PSIO by having the cartridge plugged in.
When booting with the PSIO cartridge however, ensure that an SD Card with “MENU.SYS” is present,
otherwise you will have no way of seeing a visual output from your PSIO cartridge indicating that it is in
fact booting and working.
Remember to always turn off your PlayStation before unplugging and inserting a PSIO cartridge.
Don’t forget to also adhere the included “Switch Board Sticker” to the back of your PlayStation case.
2-0: Specifications:
[2-1: Hardware]
The Switch Board is open source, and simply consists of a 4066 bilateral switch and a few passive
components. The schematic may be seen below.
If you require a replacement or would like to buy more Switch Boards for installation in more
PlayStation consoles to use PSIO on, please see our ‘Store’to purchase more completed boards.