Depends on how you do it and what kind of machine it is.
Maybe fingerfärdighet if its poking around in a trap. could be krigföring if its a war machine.
Låsdyrkning if its a mechanical device. If it's a snare or something similar used for hunting then Jakt & Fiske could be used.
I think pulling a lever to deisable a trap doesnt really need the player to roll. If they explain how they disable the trap then that might be enough. I would only have them roll if it's a mechanism they don't understand and they try disabling it.