PU‐23 diagram
The last version of the original PlayStation 1 design was the SCPH-900x. Most of these consoles have PU-23 boards inside. The most notable difference between the 9000 series and earlier consoles is that Sony removed the parallel IO port on the back. They also shrunk down the size of the board significantly.
For models SCPH-xxx1, SCPH-xxx2, you can ignore the RESET. On the other hand, the model and SCPH_xxx0, you will have to use the RESET point, and the BIOS points.All of the points are fairly easy to solder.
Here are some tips I have for you when you are soldering your chip into the PU-23.
- Cut your wires to be as short and direct as possible.
- You don’t need to connect pins one and two of the ATtinyX5 chip. Just desolder the wire.
- Use a multimeter to probe around for alternative VCC and GND points closer to where you position your chip for a cleaner installation.
- For DATA, be careful not to bridge the connection to the other resistor next to the one you are soldering to.
- Don’t apply too much solder to SQCK, or you’ll bridge the pins on the chip.
- For the wires that go into the holes, or vias, of the board: it’s easiest to stick a small 30 AWG wire through the hole, then heat the wire and hole while adding solder.
- Placing the chip on top of the chip above SUBQ and SQCK is a good spot.