This keyboard/controller is actually a bunch more interesting that I expected. I knew it had Keytronic Magnetic Reed Switches. What I didn't know is that the backlight lamps keys were Veetronix switches!
While we haven't seen any Veetronix stuff around at DT, they seemed to be popular with control panels. I have a few variants in loose form (that I got along with those mouse trap cherry switches) that I need to take pictures of.
They are plastic welded, so I'm a bit hesitant to open up the Ampex switches, but they are magnetic reed as per the US patent (https://www.google.com/patents/US3753179). I'm quite sure it's Veetronix not Vectronix and that is just a typo in the patent doc.
I did look into trying to do a backlight demo. While I was able to get some keys lit, there were a few issues. One, all the lamps are covered with dust on the inside making them pretty dim without opening them up and cleaning them. Second, it looks like this keyboard may have been running at around 30 V... I'm not risking that kind of voltage on a quick demo, I'd need carefully reverse engineer the thing before trying to turn it on.







Yep, that's a solid connector











Yes the 7 has a deeper dish, as does 8 and 9.





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