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Calculator blog


Musings and comments about our common interest

 

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Several HP41cv and cx - Half nut!!

HP41 half nut units: CV and CX 


We have received some calculators: a couple of CV units and a CX unit - all of them half-nut. 

What is a half-nut unit? The original HP41 calculators were build with two circuits: one for the keyboard and screen and another for the processor. All parts were soldered through holes, the "old way".

Around 1985-1986 HP had developed far better circuit-making, and they developed a single circuit, surface mounted with just one IC. This model (which was done as C, CV and CX too) was called "half-nut", and the previous model was the renamed "full-nut". Performance of both is identical, but half-nuts have several more "failure modes" than the full-nuts!

We test all units with the test pack of the HP41CV Service module.

It is an opportunity to get a dependable, tested and revised HP41CV  or HP41CX with the full set of memory, 

You can add some of our modules that you can find in the HP41C corner.
 
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More about: HP41cv, HP41cx
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New HP41CV units!

We now have again two HP41CV units left, with all back ports and battery side cover. It is still a wonderful machine, that can be enhanced with peripheral and modules to a still competitive machine - not in speed but in functionality. And with the legendary HP keyboard click!



One unit is a full nut and the other is a half-nut: the newer design which is more reliable since it has fewer inner parts.

Price is 130 € plus shipment.
 

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Ran out of HP41CV

I have now sold our last HP41CV. While this is a very old calculator, it is surprising how well they hold their own. Most of the half-nut machines that I have seen are still in working order. Half-nut is another story, but then these offer the possibility of conversion into HP41cl - a different animal.

I am seeing again and again the same profile: a person that had used it in the past, lost/destroyed/got stolen his calculator (with a big percentage of the latter factor), and now want to revive the joy of using it.

Probably the best keyboard action belongs to the Pioneer series, although this is debatable; but the HP41c was much more covetable than any other calculator of the time. Maybe the 67 experienced similar status in past years - but at the time, I was still using a humble 33c and in my father’s office they were using HP97s as secondary desktop computers (the main ones were the HP9815 machines, also RPN-based but that could hold 2kb of program. It was amazing seeing it driving a plotter) - so there was no way for a young student to even see a 67.

Despite being the HP41c a vintage calculator now, I can’t take out of my mind the “modern” sticker that it got in my mind. And it was modern in comparison with everything else, including my hp33c or the then top hp34c. It lived together with other calculators that had true “dot matrix” LCD screens. However, the contrast and visibility of those was minimal. And the upgradeability of the HP41c made it the dream of every engineer, even if they could not afford the additional bits at the time…

Well, now these engineers CAN afford these bits. These are the customers that are buying old HP41cv, or even the powerful HP41CL(of which there are two ready, with the latest circuit version). And if they knew that they could link it with an HP-Il multimeter like the HP3468A, they would probably do it too.

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More about: HP41cl, HP41cv
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New items in the HP41c corner

We have just included a number of additional hp41c items in the website:

  • A HP-Il interface
  • A rare, double X-memory module in a single module body
  • A touchpad module to protect the HP41c keyboard

In the next days we will include other items:

  • a Math/Stat module, boxed, with manuals and overlays
  • A Home Management module, boxed, with manuals and overlays
  • A Time Module, with manual

This way, we’ll populate the “HP41c corner” of our website. The old HP41c continues to be the most interesting calculator ever made!

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Black Friday - day one: HP41cv and HP41cx at rock-bottom prices!

 

As preparation for this “black Friday”, we will start giving low prices for selected items during this whole week.

There are three HP41CV in perfect state at 90€, and there is an HP41CX at 120€, as well in perfect state! Please contact me on the latter, since I have not put the pictures on the web yet ( sales@thecalculatorstore.com)

You know all the craze about the HP41CL. This is the most powerful calculator standing right now - if you take into account the number of ROMs that are included. We find that most of the purchasers of that calculator are old users of hp41c’s. Apparently, theirs died, and/or they lusted for additional ROMs that they never managed to find. Now it is their opportunity: they get a faster calculator, with all the possible memory, and features that no one imagined at that time (the Sandmath series of ROMs, topping with the Sandmath 3x3, come to mind)

But if you’re not ready to DIY, or not willing to shell out 600 € (but having the guarantee of a good calculator, tested and working), you can start again with one of the above: the 3 hp41cv or the one hp41cx. Remember that this latter has the extended memory, extra functions and the embedded time module too!

This offer is exclusive to the EU countries!

Tomorrow we will include more offers!

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HP41c models in our website

IMG_0127Now that I am focusing more and more on the HP41CL, it is time to get rid of otherwise perfect working HP41CV and CX, that cannot be converted to HP41CL status.

The reason for these models not being able to be transformed to CL is that they are half-nut models. That is, the processor and rest of the circuits are on a single board, as opposed to the initial models, called “full nut”, where there were two circuits. Precisely these 2 circuits made them less robust, since both circuits were not soldered together, even not slotted one into the other (like a computer board), but joined by pressure. The screws that closed both shell halts were responsible for that pressure. Any broken screw post (the know weakness of the HP41c) would not affect in principle a half nut model, while it would bring a full nut to a halt.

This is the reason that sometimes I dare to buy a non-functioning full nut in good physical state: there are good chances that the sole defect is a bad connection of both circuits, and this is solved by repairing the screw posts only.

Both machines on sale are tested, without rust in the battery contacts, and in perfect shape. All of them have the keyboard click that made HP famous.

Here are the links to both models in our webshop:

HP 41CV Scientific Calculator - USADA

HP 41CV Scientific Calculator - USADA (2)

 

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More musings on the HP 41CL

I go on playing with my HP 41cl. I was today making use of the different functions of the Sandmath module. (For the time being, I have entered the advantage PAC and the Sandmath module only. I have been using the advantage PAC for a long time and I know what’s in it; but the Sandmath is completely new for me)
In my ignorance, and having entered the latest Sandmath version, I did not read that I needed to install first the Library #4. That took me some time to find out. Once I sorted it out, I started using the number theory functions.
My elder son (9) is now learning how to factor a number in prime factors. It was nice to teach him the PRIME? and PFCT functions, so he sees that calcs have other uses apart from mere number crunching. He wanted to take it to class! He will be able to do the minimum common multiple and maximum common divisor too- that’s for next term though.
I have not made a speed comparison between the HP 15c and the HP 41cl. I will probably do it this week end (I have already ported all my 15c programs to the 41cl. I was able to make some improvements, using the additional functions of the ’cl). The more time consuming is my implementation of the IRR, using the advantage pac’s SOLVE function. For a 10 year calculation, it was taking a couple of minutes with the original calculator, and 5-10 seconds with the new one. Let’s see.
(For the to-do list: I want to browse through the multiple modules, to see which programs may be of use for me or my son. Incidentally, I will be reminded of how the world has progressed since the 41c launch.for example,the astro module tells the situation of a number of astronomy objects; same tasks can be achieved with one of the multiple apps for iPad, in graphical form, faster and more conveniently. Sorry for the digression)

I go on playing with my HP 41cl. I was today making use of the different functions of the Sandmath module. (For the time being, I have entered the advantage PAC and the Sandmath module only. I have been using the advantage PAC for a long time and I know what’s in it; but the Sandmath is completely new for me)

 

In my ignorance, and having entered the latest Sandmath version, I did not read that I needed to install first the Library #4. That took me some time to find out. Once I sorted it out, I started using the number theory functions.

 

My elder son (9) is now learning how to factor a number in prime factors. It was nice to teach him the PRIME? and PFCT functions, so he sees that calcs have other uses apart from mere number crunching. He wanted to take it to class! He will be able to do the minimum common multiple and maximum common divisor too- that’s for next term though.

 

I have not made a speed comparison between the HP 15c and the HP 41cl. I will probably do it this week end (I have already ported all my 15c programs to the 41cl. I was able to make some improvements, using the additional functions of the ’cl). The more time consuming is my implementation of the IRR, using the advantage pac’s SOLVE function. For a 10 year calculation, it was taking a couple of minutes with the original calculator, and 5-10 seconds with the new one. Let’s see.

 

(For the to-do list: I want to browse through the multiple modules, to see which programs may be of use for me or my son. Incidentally, I will be reminded of how the world has progressed since the 41c launch.for example,the astro module tells the situation of a number of astronomy objects; same tasks can be achieved with one of the multiple apps for iPad, in graphical form, faster and more conveniently. Sorry for the digression)

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