A replacement for the HP-41 zebra connector

[mfleming]

(04-22-2017 06:32 AM)Geoff Quickfall Wrote:  Back to the 41C wire wrapped connector:

The silicone tube is 2mm and the wire wrap adds another .04 mm. This is easily compressed to 1.7mm before resisting further compression. It also springs back to 2.04mm when the compression force is removed.

Geoff

Your measurements confirm my experience with differing materials. A 1/16" (1.6mm) solid cord was a bit too small for a reliable connection, while a 3/32" (actually 0.104" or 2.6mm) was too large to get a complete case closure. The closest compressible sample was a gray hollow-core cord with a nominal 1/8" (3.2mm) diameter that would compress to 0.07" (1.8mm). That material however did require a fair amount of force to compress to that height, and did not recover from compression very quickly. It had to be left alone to recover for a couple of days before it would work again.

To get something that springs back the way you've observed, I'd probably need either a solid cord with a Soft or Medium Durometer rating, or a relatively thick-walled tubing. The tubing would likely need a Medium or Hard rating in order to spring back quickly.

At this point I've heard results from about half of those who have tried the flex circuit. Assuming the others haven't encountered any show-stopping problems, I think it is worth seeing if anyone else would be interested in a replacement for the HP-41 CPU connector. I'll post a poll shortly asking for feedback.

My thanks to everyone for your comments and suggestions,
~Mark