My G5 34° joystick/jog/stick however is that button called, it works and stop working at random, it's not that is not sending any signal to the monitor, if you keep it pressed it will show the message "usb test: fail" like this:

at random it works normally, other times is not responsive at all.

I've updated to the latest firmware and the problem persists, since I've had it for a couple of years is out of warranty.

Any ideas?