Thanks for the replies. My gameport Combatstick grip looks very different inside. The pcb is very simple and has no diodes on it (see pics). The stick is from 1998 and must have an early version maybe? I will check if the matrix is the same as yours when I have the time but it looks like I will have to add all the diodes myself.
Thats the early gameport CH type. It is perfect for shift register use. I converted mine with a 74HC165 shift reg and it is awesome! I modified another later USB type which had a diode array for a friend (with a CD4021), but it required much more work. Have a look at the following thread and ask if you need help.
