HP 41C calculator

From: David Betz <dbetz_at_xlisper.mv.com>
Date: Tue Nov 16 20:37:32 2004

Thanks for all of the 41C info. I'd like to pick up a working CX
someday but they go for over $200 on eBay. I guess I'll have to stick
with my more modern HP calculators for now.

On Nov 16, 2004, at 7:40 PM, Tony Duell wrote:

>>
>> The HP 41C is gone! It's amazing how many people wanted it even though
>> it was broken. Thanks to everyone who expressed interest.
>
> I am not suprised. Most HP41 faults are just bad connections (either
> between the logic board and the keyboard/display or between the I/O
> assembly and the keyboard/display) and can be fixed easily.
>
> Corroded I/O assemblies due to battery leakage are quite common too,
> but
> they can be repaired with care and a fine-tipped soldering iron.
>
> IC failures are uncommon, but I have had the odd one. Sorting out logic
> failures is hard because the connections are made when the case is
> screwed together which means it's almost impossible to run the machine
> with the logic PCB exposed. HP used a special 'test calculator' at the
> service centres for this -- it consisted of a normal HP41 with the back
> case cut in half (exposing the logic PCB end) and modified
> pillars/screws
> to hold the logic PCB in place. I've never seen an official one, but
> making a clone was an enjoyable afternoon's work.
>
> The HP41 is still a very useful calculator. The 41C is the simplest
> model
> with 64 'registers' (a 'register' is 7 bytes...) of user memory,
> partitionable between programs and data. You can put up to 4 memory
> modules in it, each adds another 64 registers, but doing that uses up
> all
> the I/O ports. There was also a quad memory module which adds 256
> registers using just one port. And then there's the 41CV which has the
> full memory built-in
>
> The top model is the 41CX. It's a CV with extended functions (string
> handling, etc), extended memory (the ability to save programs and data
> in
> named files in another area of memory) and timer (clock, stopwatch)
> built
> in _and then some more functions on top of that, like a simple text
> editor.
>
> Add on ROM modules include things like maths, stats, circuit analysis,
> structural engineering, thermal science, financial, etc, etc, etc. And
> ssytem extensions like extended functions and timer. And 'hacking
> modules' (third party code, although AFAIK HP always made the physical
> modules) like ZenROM which let you edit the machine's memory directly.
> Serious hackers even made ROM emulators (using RAM rather than ROM) so
> they could program the 41 in machine code.
>
> And then there's the HPIL module with its extension ROMs (extended I/O,
> HPIL Development, always called DevIL :-)) which let you connect this
> little calculator to a disk drive, plotter, thinkjet printer, RS232
> interface, HPIB interface, video display, data logger, etc, etc, etc.
>
> And dedicated peripherals like a magnetic card reader, thermal strip
> printer, barcode wand.
>
> What do I have? About a dozen machines, mostly CVs, but the odd CX and
> the odd C (including a very early C with all the original bugs!), a
> couple of dozen modules, most of the peripherals, the machine code
> development tools, and so on.
>
> It's a great machine, and still very actively used
>
> -tony
>
Received on Tue Nov 16 2004 - 20:37:32 GMT