Some years ago I bought an emtiv Insight on ebay that didn’t come with a power cable, so I made one. Here is the video on how I did it:
in case you don’t happen to have the cash for a replacement cable and the high international shipping costs. The cable is still going strong and as its considerably more robust than the thin wire official cables I bought, I tend to take it out and about with me and more Insight one and the fixed sensors as punters have a habit of grabbing things and not treating them with the respect the delicate build requires.