This is a somewhat simple question, but does anyone know if the 64DD works with US Nintendo 64 systems? Another question along the same lines; what cables/other devices were necessary for the 64DD to work? I am rather ignorant on the subject.
you need a jpn n64 to get your jpn DD working, and because there's only jpn 64 dds, you absolutly need a jpn n64.
A USA N64 will work as well but you will have a problem playing the fzero expansion disk as it requires a japanese version of fzero plugged into the cart slot. All other games will work fine though. Not that much of a problem though if you remove the offending tabs from your cart slot so you can plug in japanese carts. Oh & the only thing you need to have to make the 64DD work is just a memory expansion pak. It dosent use any extra power supplys or cables, it just uses the original cables from your N64
To expand on Importaku: The N64 was practically the same machine in the US and Japan; the hardware lockout tabs inside the machine were the only difference. Either remove the plate that has the tabs (but which also holds the dust-doors) or simply file/dremel/melt off the offending tabs and keep the cart slot's dust cover intact. As Importaku said, the Japanese version of F-Zero X is needed for the expansion disk, and the 4MB pak is required for the 64DD (but seriously, as cheap as they are there's no reason not to already have one), but other than that, you're good to go.
