Here's an image of the PSU label.
Unfortunately I can't find this specific PSU on the net, neither can I find a direct replacement. It's a bit worrying with such an unusual PSU spec - after all, PSU's are usually the first thing to break.
I know Philippe has said that it must be the exact spec of 6.5V/3.85A. However, I would think that that Origin, like all other electronic equipment with on board regulation, can accept a slightly different voltage. It could also be that Arturia have some NOS PSUs. Perhaps Philippe can help us out here?