Can't See Plugin Modules

Everything about 41C 41CV and 41CX Hardware

Can't See Plugin Modules

Postby Interalia » Mon Apr 20, 2020 1:14 pm

Hello Folks

First time poster.

I live in the UK and have been a keen HP calculator user and then collector since my first HP (an HP-31E I got new in 1978).

I have this HP-41CV for about ten years. Stupidly some years ago I left it with battaries in that leaked and damaged the foil around the leftmost battery connection (when viewed from below).

So took it apart and with a bit of soldering managed to fix it and it has been worked fine since then.

I got it out again to use it today (it gets used a few times a month) and just for fun ran a 'cat 2' to list the contents of Financial 1 I have in port 1 but it doesn't list the PAC contents. I removed the PAC and tried a Math PAC I have but it doesn't see that either. I tried it in the other ports and that doesn't work either.

I suspect this may be something to do with the original battery leak and am debateing whether I should try a new battery/port foil from Calculator store.

Anyone have any advice?


Posts: 1
Joined: Mon Apr 20, 2020 12:53 pm

Re: Can't See Plugin Modules

Postby Drulli » Tue Jun 02, 2020 2:54 pm

Hello interalia,
if the PlugIn Modules are not with CAT2 but otherwise the hp is working fine, the problem is most likely, that the I/O contact assembly doesn't make good contact to the J1 contacts of the Keyboard part.
J1 provides all the connections from the CPU board needed to run the PACs,

Reasons can be:
- a misaligned I/O Assembly during assembly. Be sure that the cross webs of the underside of the connector are located between the tabs on the bottom case.
- The contact row of the flexPCB which are supposed to make contact to the Keyboard J1 connections, were indented during your recovery activities of the battery contacts. Just gently reform them a bit using your fingers.

hope that helps
HP-41 CX, HP-41CV, Printer 82143A, Cassette Drive 82161A, PILbox, 82104A Card Reader, MAth I, Circuits I
Posts: 24
Joined: Wed Mar 19, 2014 7:13 pm
Location: Germany

Return to HP-41 Hardware

Who is online

Users browsing this forum: No registered users and 1 guest