You apparently need an AC-HB1P, but good luck with that, they seem to not come up very often. I've only found a single eBay auction from two years ago, and Amazon actually has one but it's kinda sorta expensive... edit: Buying directly from that Amazon seller's site promises to be much cheaper, but judging by the lead time it's likely to turn out to be unavailable.
Kev, that plug end is the same style as a neo geo CD plug, maybe you can build one from one of those? ( even though those go fro a premium right now too) but must be more common.
Looks like it'd be cheaper to commission one to an electrical engineer if you got the specs of the AC part.
Presumably he wants an AC-HB1 rather than the P version - since it's a pretty safe assumption that the P will be 220V.
Try the chaps @www.msx.org, it's your best bet to find someone who could have one of these. It's the same style plug as for the Panasonic MSX2 FS-A1+(MKII)
Oh, no! Can you post a picture and info on the old computer (8 bit?) with television hookup? Appears to be two different voltage lines with a common ground, should be a simple build. As to the 3 box connector, you might be able to lop off a larger say six pin to fit.
