hp 41 series wire-wrapped connector question.


This is probably an easy question for some, but as I assemble my 41CL, I am curious how the wire-wrapped connector (between the Nut/Newt PCB and the keyboard/display PCB) maintain pin/pad separation? It looks like two coils of wire (see link to Geoff's pic). Is there a varnish-insulated loop every few coils to maintain pad separation? I said it was an easy question for some- just not me :-)


p.s. It looks like the serial number sticker on the back of my NEWT board is "41". Thanks Monte (Don't tell me they all say "41" ;-)

Edited: 19 June 2012, 12:13 a.m. after one or more responses were posted



In fact, it looks more like small pieces of flex circuit with single, parallel thin copper tracks (golden plated). Then the flex circuits wrap the two small rubber, silicon tubes. They are actually spare little tracks, not one single coil. I have once disassembled one of this and could never reassemble it because it broke in many parts. 8^(

As they are very thin tracks they do not shorten one pad with another in the main PCB because more than one of them fits in the space between pads. Note that there are two other separated assemblies like these - somehow lengthier - in the earlier HP41 LCD's (see this picture)

Hope this helps clarifying.


Luiz (Brazil)

Edited: 19 June 2012, 12:15 a.m.


Thanks for the good explanation Luiz. I understand that it couldn't possibly be a a single coil, but that it looked like it was.
Sorry you had to take-one-for-the-team to learn how it all worked, but we're all the better because of it. Thanks Luis.


Hi, Matt.

Please, have a look at this thread (chances are you have already seen it). For me, this is one of the best solutions for an HP41 mock up, either testing or developing purposes. But I also considered it a final solution when you have a good keyboard and wish to have a fail-proof, working calculator.

I found someone in Brazil that could provide me with a minimum quantity of 250 units, but it would cost me too much. I thought about trying to find people that might be interested on sharing the $$$ burden, but then again I missed the folks.

And you are correct: the little thing looks like a continuous wire assembly, as in a coil.


Luiz (Brazil)

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