A replacement for the HP-41 zebra connector

[Geoff Quickfall]

BIG REMEMBER (reminder) HERE

About bottom screw posts. The screws have a very short thread count, or if factory replaced at some point a slightly longer thread count. There are two types of case backs, early versions that has hex nuts hold the PCA without encasing the screw post and later versions that press down and do encase the screw posts. (Pictures tomorrow). If you are using an early version 41C with nuts holding the PCA in place you will definitely have the early case back.

The early mechanics had the nuts hold the PCA in place. The later version has the case back hold the PCA in place. The later versions ar more susceptible to overs stressing and cracking. So be judicious on the diameter of silicon tubing realizing that only two screws are holding the PCA and zebra

The Silicon tubing should be an optimal size, enough to ensure contact even during a short distortion of the case but not so large they add stress to the WEAKEST point of the 41C series except for the halfnuts. I will measure the existing tube diameter used in the most robust connector tomorrow. The least robust being the strips with wire wrap and a foam insert. Speaking of foam inserts this is the main reason for the battery/module block failure. They too, need the foam replaced due to,compression fatigue.

I just went through my 41c parts box here and reassembled 3 pre 1980 41Cs, a CV, a halfnut 41CX this weekend, three card readers and a RAM Box. I noticed in the restorations I had to reinforce and repair a multitude of screw posts.


Geoff

This connector type has a silicon tube in the middle of the curved edges:



This system has the foam strips:



These are the hex nuts that hold the early version PCA onto the contact strips (the balls and springs were for the non existent external power supply contact points):