The Museum of HP Calculators

HP Forum Archive 14

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Enhanced HP-41C
Message #1 Posted by Juergen (CH) on 23 May 2004, 3:09 p.m.

Recently, I aquired an HP-41C. At first glance, it seemed to be a normal one. But during function testing, I noticed that it had 319 memory registers. I also discovered that it understood the Time Module commands!

Well, I guess you understand that I had to open the calc. And that's what I've found:

Enhanced HP-41C

A thin PCB (green) is connected to the extension port contacts on the 41 PCB. The 4 memory modules are soldered onto the green PCB, near the border of the case so they perfectly fit into the upper part of the case. The time module is also connected to the green PCB by thin wires.

The green PCB is labeled with:

(C) HP CLUB AUSTRIA
VERSION II
BERNYTRONIX

Does anybody know some details about this BERNYTRONIX thing? Or does anybody know of similar HP-41C modifications?

Regards, Juergen

      
Nice piece! Inspiring nice piece...(N.T.)
Message #2 Posted by Vieira, Luiz C. (Brazil) on 23 May 2004, 6:07 p.m.,
in response to message #1 by Juergen (CH)

            
This could save the ports?
Message #3 Posted by Artur on 24 May 2004, 6:03 p.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

Hello Luiz,

This arrangement could let the expansion ports free? Great work! Artur

                  
Re: This could save the ports?
Message #4 Posted by Vieira, Luiz C. (Brazil) on 24 May 2004, 6:33 p.m.,
in response to message #3 by Artur

Hi, Artur;

I guess it would, because if we consider that this is what we (should) have in an HP41CV, then the addresses are consistent and there are no conflicts.

At least, this is what I guess.

Cheers.

Luiz

      
Re: Enhanced HP-41C
Message #5 Posted by DavidY on 24 May 2004, 8:27 p.m.,
in response to message #1 by Juergen (CH)

If you want to know see the PCC Calculator Journal, Volume 8, No 1. for an article (with diagrams) explaining how to dissemble a memory module and wire it into a HP41C. It explains circuit board contacts for the port bus and the hardwire mapping for memory modules.

The article shows using wire-wrap wire but apparently in your case some enterprising user(s)developed a circuit board.

It was possible to stuff 4-6 bare modules into the 41. Standard memory modules (single or Quad), Time, X-Functions,and X-memory modules were the usual candidates.

With a Quad Memory, Time, X-Functions/X-memory and two X-memory modules you had the equivalent of a 41CX with the full amount of X-memory registers added. The only thing lacking were the extra functions in the Xfunctions of a CX. And at the time of the article I don't even think HP was selling the CV never mind the CX.

            
Thank you!
Message #6 Posted by Juergen (CH) on 25 May 2004, 2:04 p.m.,
in response to message #5 by DavidY

David,

thank you much for this background information and the PPC reference. I'm sure I will enjoy reading the article!

Regards, Juergen


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