Hello Middle C,
The can definitely be replaced if need be.
Before going that route I would suggest purchasing and using some of this solution on the B buttons and kill switches -->
store.caig.com
Just spray a bit in between the top cover and button.
This will clear out any oxidization that has accumulated on the switch and should get it working as it did when you bought your mixer.
If that fails then give us a call and we'll get your unit in for service -->
serato.com