I have just installed a psx stealth 2 mod chip in my ntsc-u 75001 ps1.
here is the chip link
http://www.mod-chip.bz/catalog/stealth-modchip-p-44.html
here is the diagram with my solder points they told me to use
http://www.mod-chip.bz/Playstation/images/ST2750xonline.jpg
i have soldered in...