A few days ago I was finishing up the install on the second joystick and buttons in my PS2 cab. I am using Universal Real Arcade Sticks by Pelican. After finishing the wiring I decided I would test the controls out and see If I did it right. When I turned on my PS2 neither of my joysticks work. I plugged in a regular PS2 controller and it worked, but my joysticks wouldn't. I then tested them in my Xbox, which to my relief they worked.
I remembered hearing something about blowing the rumble fuse with 3rd party controllers if you hot swap them in the PS2. The sticks were already polugged in my PS2 when I turned it on, but I had a loose wire causing it to blow the fuse. Anyway, after much googling I found out that I had blown the PS7 regulator on the mainboard, unfortunately Radio Shack doesn't carry this small of resistor and I was about to spend the $$ on a Vibration repair kit when I found an obscure thread talking about bypassing the regulator all together.
I ended up soldering a wire to both of the legs on the regulator bridging the circuit and to my relief it worked!
If anyone else has these Joysticks I would definately suggest being careful when you re-wire them becuase you may blow the rumble in your PS2.
BTW... I am going to change all of the Treynet switches to Cherry , even the ones on the Joysticks Maybe even swap the joysticks out with a pair of Supers.