deskthority

Looks like a previous owner has removed a bunch of traces... I am guessing they wanted to handwire a different output but changed their mind. Maybe I will finish the job









Diode matrix encoding!





The only chip has 6728 date code (28th week of 1967)













The brown transistor has marking 2N3638 703. rest are all 2N3643 CDC















Cutest keycaps





NAVCOR Model 1051-C Coded Keyboard





The pcb is 3mm thick






Diode matrix front and back

Paragraphs are boring here's a list:

• The switches appear to be NAVCOR KRM linear magnetic reed (patent: https://patents.google.com/patent/US3664014A)
• My calipers measured the travel distance to be exactly 5mm
• The switch features rubber dampeners on both the bottom and top of the travel
• The reed module is soldered to a PCB inside the switch, which has jumpers soldered between it and the main keyboard PCB
• Each switch is screwed into the main keyboard PCB
• The stepped profile is achieved by angling the switches themselves thanks to their angled bottoms
• The slider is a chunk of metal to which two rivets fasten a bent piece of metal that holds the magnet that actuates the reed contacts
• The springs are pretty light

Overall I really like these switches

Unfortunately the switches are sealed shut but I did get one of them open

I'll take more photos of it but will probably remove it first