What is your PSX model!
Maybe I get to you pictures where you can check wire places and you need little processor from electrony shop. I bet that there is some shops!
And then you need programming code and programmer prog and tool!
I can maybe give programming code and programming prog but you must get somewhere porgramming tool (tool is board, you put your chip to board and connect it to your computer and run program and give programming code)
If you are expert to doing this kinda electronic job then I recommend this!
But remember you can easily broke boot chip and other components.
Steath mode mods only have little bit different programming code but if you don't want use stealth mode mods then find psx cracks from internet. those crack just hag up the protection and some cracks can shoose pal/ntsc!
Post reply if you are interested!