Installation of the 12c508 4/5-wire Mod
for a PU-18 PlayStation

Removal of the PSX cover

Removal of the laser housing

Removal of the controller/memory card housing

Removal of the heavy metal bracket

Removal of the circuit board

Mounting the chip

Making the connections between the chip and the PSX PC board

Relevant pins of the 8-pin 12c508 chip

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
              2 - Oscillator (N/C in 4-wire version)
              5 - Gate Wire
              6 - Data Wire
              8 - GND

Pin 2 -> Oscillator (N/C in 4-wire version)

Connect to #16 in the next illustration if you have a 5-wire chip designed for operation on both 100x/550x models.

Pin 6 -> Data Wire

Connect to #7 in the next illustration.

Pin 5 -> Gate Wire

Connect to #8 in the next illustration.

Pin 8 -> GND

Connect to #5 in the next illustration.

Pin 1 -> Vdd

There are two options here, a connect to 3.5V, which will operate with all chips I'm aware of, or a connect to 5V, which will give more reliable results with 4-wire chips. A 5V Vdd will operate with the chips I sell, but I can't guarantee that other vendors' parts will work.

3.5V - connect to #14
Note - this location is about 1cm to the right of pin 4 of the PIC in the first photo.

5V - connect as shown in the top photo

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.

Pictures taken from Oh! Magicom, which seems to have disappeared, sadly.