115V on Japanese 3DO

[Menegrothx]

I have a 220V-240V to 115V step down converter that I use with my Japanese 3DO and Virtual Boy. I never play on the Virtual Boy for longer than 10 minutes in a row, but the 3DO worries me. Is the voltage too much for it? I always shut down down the step down converter when I stop playing or take a break and it has never heated too much - some warmth on certain parts of the console, but I get that on my Xbox 360, Dreamcast, PS2 etc too.
So can the 115V harm the japanese machine? Or will it slowly destroy some internal parts with overheating over time? Or is it perfectly safe for playing longer 2+ hour sessions too? So far I have kept my 3DO gaming sessions pretty short, but like I said, I havent encountered any problems what so ever.