um actually wow
That is some seriously rare stuff. 1st gen fujitsu leaf springs.
Will edit with pictures
ok so this KB is the fujitsu N860-6131
Haata album
https://www.flickr.com/photos/triplehaata/sets/72157635485878451/These are vanishingly rare and only three have showed up on eBay in the last 6 or so years (to my knowlege).
Very linear, though mine isn't that great until I finally finish refurbing it. HaaTa's is fully refurbished and he brought it with him to Keycon.
He may be willing to help convert it as there are now three people with one that want it to work on USB, but we'll have to do some research into it. Usually the hardest part is finding a plug. We'll also need datasheets and pinouts of all the chips on the PCB.
Mine and his are from the sanyo MBC1000 computer (which was very very cheap at the time, oddly enough) and dates to roughly 1982.
The same KB was used for other computers too, I think the MBC2000 and 1500 had it as well, but I will have to doublecheck that. You can see them in pictures of the sanyo early PCs of the time.
OK hope this helps! Great find and a total steal of a price too. Yours appears to be in better shape than mine making it one of the best-condition examples known. Treat it right!
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I note that my flickr doesnt have my pictures of it yep: uploading the ones I took now.
This KB actually has some really interesting legending techniques. 4 in total.
1. doubleshot
2. doubleshot blank then engrave through the first layer
3. singleshot, engraved and then infilled
4. doubleshot, engraved and then infilled (no idea why).
OK let me know if you have any questions or whatever.