Nascom 2 keyboard connector

I've now taken a look at that.... Initially I was puzzled. It makes no sense at all if the keys are simple switches.... Tell me (as I can't get to my Nascom at the moment), how many connections does each key have? My guess is 4. Moreover, I will guess that there are 2 pairs of pins that are dead shorts to each other, but one pair is insulated from the other. And that this doesn't change if you press the key. My guess (again) is that these keys are actually magnetic. There are 2 loops of wire trough a little magnetic torroid core. Pressing a key brings a magnet against the core, changing its magnetic properties, anf thus the coupling between the loops. Each of the lines on the matrix in the schematic is a set of these loops in series. Horizontal lines are the sense loops, vertical lines are the drive loops. That would explain the cryptic comment on the schematics that the order of keys in the matrix may not be the electrical order on the PCB. Now for an amazing coincidence (if my guess is right). As you probably know, I've had an HP9845B on my bench for the last few months [1]. Last weekend I finally finished working out the rear section with the processor and memory boards, the PSU, etc, and started on the keyboard assembly. Tge keyboard is exactly as I've just described. The electronics is somewhat different to the Nascom 1 keyboard, but the 'switches'[2] may well be the same. Hmmm... [1] My advice to anyone with a non-working 9845 is to find some other mug to fix it. If you're not that easily put off, I will try to answer hardware-related questions. [2] Most of them have 4 pins, as described. The arrow keys have 6, one drive loop and 2 sense loops. The reason is that said keys contain 2 core as they kave 3 postions -- up, pressed gently (single cursor movement) and pressed hard (repeated cursor movement). Well, it _is_ an HP... It can't be a keyboard detect line. It goes to a TTL input, which would float high anyway. It was probably easier to use an 8 bit buffer on the CPU board, and there was no good reason not to wire all 8 inputs to the keyboard connector. The first 2 could be used as general-purpose outputs... NMISQ/ is somewahat like the reset input, but it produces an NMI (Duh...) I wondered if it was used for the break key or something, Apparently not. -tony