you should be able to look at a label somewhere on the unit, they always have the voltage rating on there somewhere
with my experience…(i used to live in italy which is pretty much all 220v stuff) if you plug in something that needs 220 or 240 volts into the wall that provides 110-120, it’ll just run shitty (ie: disc reader motor running slow or not powering on at all)
you should be able to find it on the unit. i’m not sure how much voltage japanese products require, but i think the US is one of the very few that only run 110-120 outlets (most other countries use 220-240v rather than 110-120v to prevent accidental electrocution…from what i’m told)
EDIT:from http://www.japan-guide.com/e/e2225.html
“The voltage in Japan is 100 Volt (like Superking said), which is different from North America (110V), Central Europe (220V) and most other regions of the world. Japanese electrical plugs have two, non-polarized pins, as shown above. They fit into North American outlets.”
“Some North American equipment will work fine in Japan without adapter and vice versa, however, some sensitive equipment may not work properly or even get damaged. If you intend to purchase electronic appliances in Japan for use outside of Japan, you are advised to look for equipment specifically made for oversea tourists.”