A lot of consoles you can swap the psu for a local one.
Xbox 360 just use the equivalent local brick to use an import, fats and slims.
Some PS3 consoles have internal PSU with universal voltage, idk if all of them do but some of the early Japanese fats you just swap the cord for a local one (they will run on 240V power) - this is the way people here actually get to use a full hardware BC fat PS3 as we never had a launch fat with that gear (only the software BC version was released here).
PS1 & 2 slims have external power supply providing DC to console so you just swap that for your local.
PS2 fat - I've seen the internal PSU of a Japanese import swapped out for a local equivalent.
Think the only console I have that actually needs a step down transformer is my launch Japanese PS1
