A600 Mouse Problem

[Pat the Cat]

Way more likely to be malware than hardware if both options crap out after a few tries. They use totally different hardware.

You could try monitoring the CIA pin with a logic probe to see if it bounces up and down when you click.

There's not much in the way of components - one resistor inline with the button, one debounce capacitor  between ground and the connector pin on the back.

[Pat the Cat]

Makes no sense at all scuzz. If a utility shows it as working, but a Workbench does not, it's got to be a software problem with that Workbench disk.

Denise doesn't read the button, it reads the position (mouse quads). That's all working.

OK, no sockets, you can't swap the CIA chips to test the button press. BUT you can check the button with Early startup menu at least.

[Pat the Cat]

https://www.everythingamiga.com/2016/11/amiga-2000-weird-mouse-issues.html

Might not be the CIA, can be the connections and components leading to it.

I would at least try changing the components between the CIA and the mouse port before  writing off the CIA chip as bad.

That capacitor, if its Esr was too high, could cause the issue. Increased resistance rather than no contact at all.