HP 41CV key problem

[Trond]

Hi folks! I briefly mentioned this before but here we go:

My HP 41CV is in excellent condition, except for one thing: the keys on the second to last row (x, 1, 2, 3) are a bit harder to press, does not make a "click" sound, and sometimes do not to register when I press a little too loose. All the other keys feel great, and I literally can't miss a stroke even when I try to press lightly. I have found that it annoys me, so I am using this calculator far less than I would like. Any suggestions here?

Thanks in advance for your time!