Stepping down the voltage is the correct solution. Running it at 120 volts can cause problems... for example if a secondary voltage somewhere inside the unit is, say, 34 volts and there are 35 volt capacitors, then 120 volts on the primary will increase the secondary voltage above the rating of the capacitors and...poof. So unless you are dead sure about the voltage ratings of the parts inside, step down the voltage to where it is supposed to be. Simple physics, not misinformation.
