Installation of the 12c508 4-wire Mod
for a PU-20 PlayStation

Removal of the PSX cover

• Turn unit over and remove the 6 screws.
• Turn unit right-side up, and lift the cover off.

Removal of the laser housing

• Disconnect the flexable PCB by pulling straight up on the black connector. This will release the board, which can then be removed, by pulling straight up.
• Disconnect the power connector (3 grey + 1 white wire) by pulling straight up.
• Lift off laser housing.

Removal of the controller/memory card housing

• Remove the two screws.
• Disconnect the ribbon cable by pulling straight up.
• Lift off the controller/memory card housing.

Removal of the heavy metal bracket

• Remove the 5 (?) screws holding the bracket in place.
• Lift off the bracket.

Removal of the circuit board

• Remove the 5 screws along the top edge.
• Lift off the circuit board.

Mounting the chip

• Carefully bend the the pins of the chip so they are parallel with the chip. Now when the chip is placed right-side up, the profile is much lower.
  

• Locate the site to install the chip. It is located on the underside of the mainboard near what would be the front right corner of the board when the board is normally oriented.

• Insulate the chip from the main board. I attach a piece of electrical tape to the board and place the chip on top, then once the whole process is complete, put another piece over the top of the chip, insulating it from both board and shielding.

Making the connections between the chip and the PSX PC board

With the chip right-side up and the notch at the top, pin numbers are read counting down the left side from 1 to 4, and up the right side counting from 5 to 8. Pin 8 is located directly across the chip from pin 1.

	      1 - Vdd
              5 - Gate Wire
              6 - Data Wire
              8 - GND

Pin 6 -> Data Wire

Pin 5 -> Gate Wire

Pin 8 -> GND

Pin 1 -> Vdd

That's all there is to it. Be sure to insulate the chip from the metal plate on the bottom of the PSX. Now, just reverse everything you did to take this thing apart, and you're done. Fire it up and play your imports without having to swap ever again.