HP 41C calculator

From: Joe R. <rigdonj_at_cfl.rr.com>
Date: Wed Nov 17 09:58:03 2004

At 09:37 PM 11/16/04 -0500, you wrote:
>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.

  There's a reason that used HP-41s bring over $200. The modern HP calculators bite! Once you get used to a 41 you'll stick to it.


>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 Wed Nov 17 2004 - 09:58:03 GMT

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