I did not have this as a reference when attempting my first controller mod or pad hack. This is very handy for any controller mod type, ie: making a custom joystick. There are also many more controller/PCB diagrams on
SlagCoin, just posting some of the ones I am currently using or have used in the past for some of my mods. Enjoy!
ps- Diagrams are pretty self explanatory but if you have any questions, feel free to ask in the comments sections
Original Xbox S controller (late model)
Original Xbox S controller (earlier model)
Xbox 360 controller (late model)
Xbox 360 controller (earlier model)