You can download this modchip installation tutorial here OR you can follow the directions online (they are the same) :

You should know the following:

Opening your PlayStation WILL void your warranty.
Installing a Mod Chip WILL void your warranty.
Some older model 100x Playstations ARE UNABLE to read CD-R media
- This is due to the old/worn out/out of alignment laser inside the unit.
- Please VERIFY your model before ordering a mod-chip.
We are not responsible for ANY damage occurring to your PlayStation as a result of installing this chip.
We are not responsible for any changes Sony may make in the future to alter the functionality of a mod chip.
We are not responsible for any copy protection schemes that any company may come up with to alter the functionality of a mod chip.
Incorrectly installing a Mod Chip WILL result in damage to your Playstation.
We are not responsible for any physical, mental, monetary or ANY damages occurring to ANYTHING or ANYONE regarding the installation of the Mod Chip.
Chips are tested prior to shipping to assure they are working. We are not responsible if the chip is damaged by you during installation.
- It is left to our discretion if the chip was damaged during installation.
All returns are subject to a 15% restocking fee as well as shipping costs.
A Mod Chip is NOT a product of Sony.

If you are not confident that you are capable of soldering then please find someone who is before ordering.

Incorrectly soldering a mod-chip WILL RUIN YOUR PLAYSTATION!

Needed Tools:

Disassembling your PSX:

Step 1: Remove the PlayStation cover: Turn unit over and remove the 6 screws. (Some units have 5 screws) Turn unit right-side up, and lift off the cover.
Step 2: Remove the laser unit: Gently remove the wires coming from the laser unit. Make sure to hold the ribbon cable right where it goes into the connector. The ribbon comes out of the connector, the connector is NOT part of the ribbon cable, so do not pull on the connector as you can break it off the board. Just lift up the laser unit and put it aside. Remove the ribbon cable coming from the gamepad connectors, again do not pull on the connector, the ribbon comes out of the connector, Remove the cable coming from the power supply, it just lifts up and out of the connector on the board.
Step 3: Removing the metal bracket: Remove the screws holding the bracket in place. Lift off the bracket, it may be snug, try lifting it at the back first and then popping it off.
Step 4: Removing the circuit board: Remove the screws along the top edge. The circuit board can now be lifted up and turned over.