Blue Point YA7707 Test Box

Looks like Mouser has a bunch of them to choose from. It's a generic potentiometer, so as long as it fits and you're willing to do some soldering you should be fine. The problems I see are that 1) it may not have quite the same points on the rotation for the same resistance levels and 2) a new unit would probably be cheaper or at least a wash after you factor in time and frustration.
https://www.mouser.com/c/passive-components/resistors/variable-resistors/potentiometers/?q=100k