North American voltages vary wildly from 110-120 and 220 to 240v. It generally doesn't hurt a modern power supply as the regulators can take the voltage but for the sake of simplicity sometimes you can have multiple voltages you can set to if you want to be really region specific or offset for different frequwncies. Most likely the last person set it to 100 or 120v and plugged it in, blowing everything up in the process. I've found an ImageWriter II on this side of the pond that acted partially brain dead until I noticed it was set to 230v.