Installation of the 12c508 4/5-wire Mod
for an 52-pin QFP PlayStation
Removal of the PSX cover
- Turn unit over and remove the 5 screws.
- Turn unit right-side up, and lift the cover off.
Removal of the laser housing
- Disconnect the ribbon cable by pulling straight up on the black connector. This will release the cable, which can then be removed, by pulling straight up.
- Disconnect green connector (3 grey + 1 white wire) by pulling straight up.
- Disconnect collection of rainbow colored wires by pulling straight up.
- Lift off laser housing.
Removal of the controller/memory card housing
- Remove the 5 screws holding the thin metal bracket in place.
- Lift off the bracket.
- 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 3 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 area near the upper right corner on the back-side of the board. You will see 2 large chips. One, an SEC Korea chip and the other, the 52-pin QFP. The instructions that came from the chip manufacturer specify an 52-pin QFP chip (JASH9605E). This number is not correct. In this case, all 52-pin chips are the same. So, if you have an 52-pin QFP, this mod should work for you. The pins on this chip aren't numbered, but they follow convention. While looking at the chip, so you can read the writing on it, the pin on the far left along the bottom edge is pin number 1. Count up as you go along the edges of the chip, in the counter-clockwise direction. This will place pin 52 just to the left and up a bit from pin 1. If this is confusing, look on the front of the board, many of the chips have their pins numbered there.
- Carefully glue the chip upside down between these two chips. (A small bit of silicone works nicely, but its your call).
Making the connections between the 12c508 chip and the PSX PC board
Relevant pins of the 8-pin 12c508 chip
With the chip right-side up with 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 - Vcc
2 - pin 15 of QFP (n/c in 4-wire version)
5 - pin 2 of 082B
6 - pin 17 of QFP
8 - GND
Key for subsequent diagrams
Pin 1 -> Vcc
Locate a 7805 regulator approximately 3 inches diagonally up and to the left
from the bottom right of the board. This regulator will only have three pins
on it, all on the top side of the chip. Connect pin 1 on the 12c508 to
the leftmost pin on the regulator.
Pin 2 -> pin 15 of QFP (oscillator - not connected in 4-wire)
Pin 5 -> pin 2 of 082B (gate wire)
Just to the left of, and about 1.75 inches below the SEC Korea chip.
Pin 6 -> pin 17 of QFP (data wire)
Just above that same chip.
Pin 8 -> GND
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.