Just picked up a 1976 Hacker HCD 1000 Cassette deck, in original box with operating instructions and brochure. Though I believe no service data included. Probably hen's teeth! Checked my stock but nothing doing. Nothing on the web either, one manual did sell on e-bay two years ago (see below). I believe is made by Nacamichi Nakamichi .
Sorry to be picky but the Company is Nakamichi I think. Having said that I also think you are right as it is written both ways!
Oops, that'll teach me to just take a singular source on face value.
https://www.vintage-radio.net/forum/showpost.php?p=582959&postcount=12
It's definitely spelled Nakamichi - I have five of their decks: two 1000ZXs, a 600ZX and two BX-300Es. I think the word is Japanese for "bloody heavy" - at least, that's what I thought when I first picked a 1000ZX up! A mate has a 'Dragon', bought faulty from ebay. We fixed that one evening at work!
It'd be quite a coup if the Hacker Brothers managed to get Nakamichi to make a machine for them, I didn't think they did that sort of thing.
I think I prefer my Tandberg though.