PU-22 DFO installation diagram (dual frequency oscillator)

This is my favorite version of the PlayStation 1. It’s in newer systems, so the lasers are more likely to still be in good condition, but the system still has both the serial and parallel ports on the back. This board was used primarily with the SCPH-7500 series of systems.

For more information about PS1 dual frequency oscillators click here, for more information about PS1 mods click here.

PU-22 DFO installation diagram

Below are two diagrams. The first one shows the top side of the console board. The second one shows the bottom side of the console board. You can install the DFO on either side. In either case you want to make sure the installed board isn't making contact with any of the console's metal shielding.

When installed on either side you will need to do at least some work on the top. The top metal RF shield needs to be removed, and the small 220 ohm resistor marked in orange needs to be removed. This will uncouple the onboard oscillator from the graphics chip.

If you are a beginner, or just looking for an easier installation experience, I'd say the top installation is a little bit easier. Installation onto the bottom requires soldering to via holes for S0, CLK, and 3.3V. When installing onto the top you can get away with only soldering to pads.

Click on the images to see them in a higher resolution.

PU-22 DFO installation diagram (top) PU-22 DFO installation diagram (bottom)

Installation tips

Here are some tips I have for you when you are installing the DFO onto your PU-22.

  • Cut your wires to be as short and direct as possible.
  • Installation onto the top is a little easier.
  • You can remove the 220 ohm resistor on the console by heating it up with a soldering iron. Quickly switch between heating up each side until it comes loose.
  • If you have a hot air rework station you can remove the IC204 clock chip and use the onboard 220 ohm resistor. Remove the clock chip, leave the 220 ohm resistor installed, and then connect CLK from the DFO to the crystal side of the 220 ohm resistor.