The only people that need to be concerned about running Japanese consoles are Europeans or those living in other PAL countries where the voltage is 220v.

If you live in any country (Canada, US, etc) that use 120v, there is no concern whatsoever.

The only real concern is to check to make sure power supplies for retro consoles are still in good condition. Never use a power supply that's been significantly damaged and wasn't repaired by someone who knows what they're doing.