Broken volume knob

[mnok]

I have a cort A4, an older model which I don't see on sale any more - had it about 18 years now but the volume knob broke some time back.
The pot on it has a function where if you pull it, it clicks. I think someone told me once that this switches between active / passive mode but I don't know. Now if you pull it, the knob comes out - there's nothing really holding it in place but it still works so I never bothered to fix it. I'm not sure if I need a new pot, knob, or both - could someone help me diagnose the problem?

The knob has a little allen key screw in the side of it which I assume is how you were supposed to remove it before, I think I'll likely need to replace the pot but I don't know which type this is or what I should replace it with.

 

[Crater]

I presume the aluminum shaft is still sticking out of your bass when the knob comes off, since you say the volume's still working. That's the pot's shaft. As long as the knob is off, make sure that nut that holds the pot down is snug, but not too tight.

Have you tried tightening the set screw back down? Or is the screw gone? You might find set screw in the Tiny Screws Bin at your local hardware store, since this bass is an import it's likely to be a metric screw. You'll need a set of (probably metric) allen keys too to tighten it down when you get back home...

Just buy a new knob, it comes with a setscrew and it "upgrades" your bass' tone every bit as much as installing an 'orange drop' tone cap does.

To test if the push/pull is an active/passive switch: remove the battery, if the bass works in one position but is silent in the other, then it's an active/passive switch. By the way, even with active/passive switching, the battery is still connected and draining current whenever there's a cord plugged into the output jack. The pull knob does not cut off the battery, so always unplug your bass when you're not playing.