Mayumi V4 with Breakout PCB

I HIGHLY Recommend the PSNEE instead of Mayumi as it supports all regions, is an easier install and is more reliable. 

You can grab one HERE

Mayumi is a 8 wire install and will work on any Ps1 revision except for the early models with the Av Jacks (Pu-7 / Pu-8)

Keep in mind that Pal games will likely have display issues to the 50htz to 60htz differences. 

These chips are programmed to work on North American consoles (NTSC-U) if you have a Pal or NTSC-J console, this will not work for you. 

For install Diagrams I'd recommend checking out Quade's Page Here!