Keyboard (ENTER) fix for vintage 12c?

[lemontea]

I got a 12c off eBay a while back and that was one of the first things I ever bought on eBay. Not really knowing my way around I got sort of suckered into a 12c that had a lousy Enter key. I just kept it.

I hardly use it; I only use the scientific ones now.

So, is there a fix for this?

The key works but there is no more "bounce" to it (not the bad kind of key bounce, it just doesn't feel like it has any springiness). I don't remember what the keyboard construction is. Is it a membrane with little bubbles that the key compresses? Is said bubble "popped" on the 12c?

I recall trying to open it up but then I was faced with a big wrapper of heavy black paper, and didn't go further.

Just curious. This is not a super important fix. I've left it like that for years, sitting around.