psx-psu-sch1.png
psx-psu-sch2.png
psx-psu-sch3.png
psx-psu-sch4.png
psx-psu-sch5.png

psx-pio.pdf
psx-digital-in.pdf
psx-digital-out.pdf

NOTE!
I don't know if any of these schematics are correct and working, I just found these from somewhere.
Use with caution and don't blame me if you fry something.