Re: PC Engine Duo-R Power Adapter
I don't have a duo r, only duo, pce, ifu 30 and sgfx.
The Genesis 2 adapter won't physically fit my duo, but based on what you've read it should fit a duo r. Specs are close enough, but the Genesis 2 has a little less punch than the regular duo one, again of it works or is not an issue. Polarity matches as well.
Why don't you want to use the Japanese power supply? With a common regulator you should have no problems at all.