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Calculator blog


Musings and comments about our common interest

 

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Repairing the rusting battery bay of HP41c.

You may have bought an HP-41 in EBay, just to find that the battery bay is utterly rusted. There goes your investment! Maybe you wanted it for CL conversion - maybe it was your first 41c and you wanted to see what’s all the fuss about it!


Whatever the reason, letting the rust inside your calculator is a recipe for later disaster. It will corrode the circuit lines, communicate to other parts of the circuit, destroying your investment (and, in the case of the CL, it IS an investment!)


You can easily buy port covers, even battery cover; but it is much more difficult to find this piece in internet. And with a good reason: it is the first thing that fails in the HP41c, and therefore you can only salvage the other parts.


Well, there is an option: you can buy in our shop the adhesive circuit that adapts to the plastic body of the battery connector. It has an extremely strong bonding, and the shape is perfect for the task. I have to say that it is a little difficult to put it properly: you need a firm hand and some experience to do it. I would not recommend to buy one to repair your only calculator, since it will not work properly the first time. At least it did not work for me the first time, but I got the experience of what failed. The second time went well already. So, my advice is: if you want to repair just one calculator, you’ll be better off buying two. If you’re repairing more, then n+1 - so that you can afford one error. Or you may be more skilled than me - in than case buy just as many units as repairs you need to do.


The circuit comes with clear repair instructions, but I would stress the fact that you need to bend it properly to shape beforehand, using the guidelines, and that you should start in the cavity between both ports.


I have used it to repair a calculator that would not start, and that I bought in internet as “for parts”. Now it is my CL. Today I have just repaired a non-working CV - this time keeping the original board in. This will end up in another CL as soon as I receive the new boards, with Sandmath 2x2, among other new features.


Please take a look at the beautiful finish of the battery once repaired.

IOBLOCK_REB_ITN.jpg

DSC_0170.jpg

DSC_0171.jpg

You can find it here.

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Calculators for the Iphone 5

i41cx review

My former telephone died and my wife got me an iPhone 5. Then I set to get some calculators to work with in the system. In particular, I downloaded all the free ones. Here's what I got:

I did not load the HP15c in any of its versions, since i always carry one with me. I find that it is the finest device ever made for personal calculations, only rivaled by the mighty HP42s - but this is a completely different discussion...
I took the free version of the HP42s, Free42. It is built for the smaller screen of the previous iPhone versions


I got RPN25 calc. When you need a simple, RPN calculator, this is a nice alternative, since there are not too many keys and it has the basic set of functions. Also for smaller screens, but it is a pleasure to use.


I got a very simple RPN calc, iRPN Calc, which is as simple a calculator as you may find anywhere, with a very nice twist: you can change the items in the stack by moving them around with your fingers. Also for smaller screen.

 

I48. not built for the iPhone 5 - there is a wide white band in the lower part of the screen - it is in need of an adaption or at least a recompiling, in order to be livable with in the iPhone 5.


PowerOne SL: does not try to mimic the original HP calculators, and it is the first one that does fill the whole screen. It opens as an algebraic model, but when going to the settings page, you can change it into RPN. It has several pages for different functions, from numbers, angle functions, other transcendental functions, and memory registers. This is a fine addition to the screen.

 

The i41CX+

One of the calculators that has marked my scientific life was the HP41cv. This was a machine that offered a young engineer the promise of doing anything - from controlling peripherals to all kinds of calculators. I have been following with attention the HP41cl developments, and I find extremely interesting the old, loved 41c body with throughly modern innards - and sometime I will get one. But it just does not fit in my pocket.

Therefore I took the plunge and download the full version i41CX+, with CAS. Let me state first that I have not been able to delve into the CAS, since I have been exploring the different modules available (the CAS is one of them). It works basically as the original one, and it has been adapted to the longer screen of the iPhone 5. Lest I forget, it is not free, but close to 25 € (once bought, you cannot see the price in the store). Let me say that it fully justifies the purchase.



You can download a huge number of modules - among them many I have not heard about; and you can download as well all the overlay layouts that go with them. It works exactly the way the original did - with the difference that it can run much, much faster.

 

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The HP48SX


I have now besides me a mint unit. No box, slightly used pouch, but absolutely mint body, screen and keyboard. As you can imagine, I have a quite good supply of HP calculators, and I have to say that the initial models of the HP48 family were probably the most beautiful, highest quality calculators HP ever did. Later green-based models were not as beautiful for my taste (plain ugly, I would say), and keyboard quality would be worse in some later models (I would say the latest G/GX versions, not the prior ones)

DSC_9416.jpg

I don't know why HP departed from the brown color of this 48SX. The orange, white and blue colors of the additional key functions are very readable (less so the blue than the others, but still very much), and the matt tone of the background makes a pleasure to work with this calculator on the heave light of many offices or classes.
The only bad point compared with what HP is capable is the screen. The blue color LDC is much more difficult to read than the current LDC screens of the HP50g or the newest HP39GII. Now it seems uncomfortable - but I have the same sensation when I start working again with the acknowledged top of RPN calculators - the mighty HP42s. Contrast in that screen is minimal, when compared with the newer HP17bII or the old HP15c. Nevertheless it remains the calculator of choice for many things, since it fits perfectly in the jacket pocket.
The keyboard in the HP48SX has the same feel of the Pioneer family. It is one of the best HP has produced, but still after the HP41c family, which for many were the best keyboards HP produced. (While it may seem blasphemy, I think that the keyboard feel of the current silver HP17bII+ is excellent, and it is my every day office calculator. As it is thicker both in body and in its pouch than the Pioneer series, it does not fit comfortably in a jacket pocket - I carry there a new HP15c LE)
I see that today I am diverting too much from the original aim of today's blog: the HP48SX. Coming back to what I was elaborating. The keyboard visibility is higher than today's graphical models, with the exception of the HP50g Blue; the keyboard organization seems better to me; the color scheme is unsurpassed to date, in the HP48 series or in any other series, for that matter, save for the voyager series; and the keyboard feel remains among the best.
It is just that it does not make sense to me to get accustomed to a 20-years old system that has been superseded by more modern and complete models like the HP50g. If it was instead RPN, I could live with that; I have hard time to make more than very basic programs in RPL; my mind is wired in either basic-like languages or RPN; but RPL, despite being very close to RPN, is substantially more complex to follow than RPN. YMMV, of course.
Please take a look to the article of Mr. Wickes, one of the creators of the RPL concept. It is in the HP journal of June, 1991. You can find it in the url below:
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1991-06.pdf
(By the way, there are many articles worth looking at in this journal series. It is a testimony of the HP quality of that time, that resources were allocated to create interesting, well documented and produced company newspapers like that. 
To find a list of articles in the series, in order to look for a particular subject, go to this link: 
http://www.hpl.hp.com/hpjournal/pdfs/HPJ_catalog.xls
All the Journals were digitized from 2006 onwardsI have now besides me a mint unit. No box, slightly used pouch, but absolutely mint body, screen and keyboard. As you can imagine, I have a quite good supply of HP calculators, and I have to say that the initial models of the HP48 family were probably the most beautiful, highest quality calculators HP ever did. Later green-based models were not as beautiful for my taste (plain ugly, I would say), and keyboard quality would be worse in some later models (I would say the latest G/GX versions, not the prior ones)

I don't know why HP departed from the brown color of this 48SX. The orange, white and blue colors of the additional key functions are very readable (less so the blue than the others, but still very much), and the matt tone of the background makes a pleasure to work with this calculator on the heave light of many offices or classes.

 

DSC_9417.jpg

 

The only bad point compared with what HP is capable is the screen. The blue color LDC is much more difficult to read than the current LDC screens of the HP50g or the newest HP39GII. Now it seems uncomfortable - but I have the same sensation when I start working again with the acknowledged top of RPN calculators - the mighty HP42s. Contrast in that screen is minimal, when compared with the newer HP17bII or the old HP15c. Nevertheless it remains the calculator of choice for many things, since it fits perfectly in the jacket pocket.

 

DSC_9418.jpg

 

The keyboard in the HP48SX has the same feel of the Pioneer family. It is one of the best HP has produced, but still after the HP41c family, which for many were the best keyboards HP produced. (While it may seem blasphemy, I think that the keyboard feel of the current silver HP17bII+ is excellent, and it is my every day office calculator. As it is thicker both in body and in its pouch than the Pioneer series, it does not fit comfortably in a jacket pocket - I carry there a new HP15c LE)

 

DSC_9419.jpg

 

I see that today I am diverting too much from the original aim of today's blog: the HP48SX. Coming back to what I was elaborating: The keyboard visibility is higher than today's graphical models, with the exception of the HP50g Blue; the keyboard organization seems better to me; the color scheme is unsurpassed to date, in the HP48 series or in any other series, for that matter, save for the voyager series; and the keyboard feel remains among the best.

 

It is just that it does not make sense to me to get accustomed to a 20-years old system that has been superseded by more modern and complete models like the HP50g. If it was instead RPN, I could live with that; I have hard time to make more than very basic programs in RPL; my mind is wired in either basic-like languages or RPN; but RPL, despite being very close to RPN, is substantially more complex to follow than RPN. YMMV, of course.

 

Please take a look to the article of Mr. Wickes, one of the creators of the RPL concept. It is in the HP journal of June, 1991. You can find it in the url below:

 

http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1991-06.pdf

 

(By the way, there are many articles worth looking at in this journal series. It is a testimony of the HP quality of that time, that resources were allocated to create interesting, well documented and produced company newspapers like that. 

 

To find a list of articles in the series, in order to look for a particular subject, go to this link: 

 

http://www.hpl.hp.com/hpjournal/pdfs/HPJ_catalog.xls

 

All the Journals were digitized from 2006 onwards)

 

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Why using a handheld calculator nowadays - part I

Many people, when they see me using a calculator in my job, argue about why using now a calculator, when there are so much more powerful alternatives. They always try to convince me about how much better is a spreadsheet, etc.

Let me try to organize my thoughts about what's the point of having a calculator nowadays, when we have computers and, let's not forget, smartphones. If you are reading this, chances are you are as nut about calculators as myself, and you are as well faced with those questions from time to time. I hope then I can give you some elements for discussion. I would like to ask you to post your own reflections, to reinforce my arguments as well.

(Other times I get challenged about collecting calculators, but for that, to be honest, I haven’t found any good argument in our defense!!)

Alternatives

In order to systematize the discussion, let’s see first which are the most likely alternatives to your calculator (the most likely, not all of them. Remember the HP-01? Or more typically, the Casio watch calculators?)

  • PC running spreadsheets
  • PC running specialized mathematical software (Vgr. Mathematica)
  • PC running a calculator program
    • The operating system’s own calculator
    • Emulated “true” calculators
  • Smartphones
    • Own calculator
    • Calculator Apps
    • Ipads and other tablets

In this post I will deal with the first ones, leaving the others for a further post

PC running spreadsheets

On one side, it is true that an spreadsheet carries you further and with less effort - and it leaves a trace of what you are doing. You don’t need to write with your pencil the intermediate results.

Today spreadsheets have very powerful instruction sets. And it is very likely that what I now think that can't be done with spreadsheets, is more due to my lack of knowledge of the tool than actual lack of that feature. I am now thinking of all matrices-related things. 

PC running a mathematical software (like Mathematica)

I have to be honest with you – the last time I used one of these, I was still using MSDOS, when I was studying engineering in the 80’s. For me, this option is limited to Academia – which is the environment that would buy and maintain this kind of software. I have to confess that my opinions on this area are based on very out-dated information, and I cannot add value. (here is where you, reader, can join in!)

Before the IBM PC was born, there was a Personal Computer produced by HP – the HP85. It was a fantastic machine, running a BASIC-oriented operating system, with a big number of mathematical operations for the time, and that could be programmed for any kind of mathematical challenge. In this case, some of you could tell me that it was not an alternative to calculators: it was, in fact, a calculator (its CPU was based on calculator CPUs, at a time where 6502, 8080 and Z80 microprocessors were common on other machines)

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There were ROMs that enhanced its capabilities in areas that are the realm of calculators: matrices, etc.

PC running a calculator program

I am running in my Mac a couple of different HP15c, a HP42s, a HP41cx, and under the Windows screen in parallels, a HP50g. Even the most advanced scientific calculator (the wp34s), started its life based on the SDK of the 20b  - if I am not mistaken. I have written a blog article for the humble Mac OSX calculator, that can be configured as RPN as well.


The choice would be even bigger, were I running Windows as main machine. I have not explored the options for Linux. I might be interested if I still was in the Windows camp, but I moved to Mac and I’m not thinking about changing again.


The discussion of the many working alternatives for calculator programs is well beyond the scope of a single post, and deserves an article or a series of articles from somebody much more knowledgeable than yours truly. Let’s focus instead on the advantages and disadvantages:

  • Advantages:
    • Speed: several orders of magnitude running programs, except in case of the latest calcs, like the wp 34s, hp 50g and hp 30b
    • You can have all the options – you are not limited by memory or bays used, like in the HP 41c family, or the HP71b
    • In most of them, the numeric keyboard works as well, as most of the basic operations. The keyboard shift works as F.
    • In some of them, there are side windows that can show the status of the internal registers, from seeing the whole stack and last x registers (good), to seeing all the CPU registers and flags (geeky).
    • You can take all your calculators with you, instead of being limited to 2 or three. (I seldom travel with 2 calculators – most likely I take 3 with me: the hp 15c in my jacket pocket, the HP17bII for calculating at work, and either the hp 50g or wp 34s for fun at the hotel.

  • Disadvantages:
    • You need to switch on your computer, and then you need to look for the application and switch it on as well. This takes 1 minute – unless you’re working with Mac – then you’re going after 16 seconds. Let’s see what Windows 8 brings to the table.
    • In many cases, the calculator does not keep the state you left previously: stack and memories. This is not really a problem of the idea but of the implementation.
    • There is no comparison between keying in in a physical keyboard and doing it with a mouse.
    • It occupies real estate on your screen, the same as a calculator occupies real estate on your desk – however, screen estate feels always smaller and cramped than your own desk. (by the way, this is the reason that my HP19bII never takes a lot of use – same as with the HP71b.
    • If you are using it in conjunction with Excel or other program, the switch from one to the other is never instantaneous – you need to click twice on the window – once to select it, another to start doing what you wanted. This happens between any two windows applications, by the way. 

There are times when you can’t use a computer – meetings!

There are two kind of meetings in my company: with and without computers. When you see a meeting where everyone is using a computer, you can assert than more than 50% of the attendees are not really there, but emailing or finishing their presentations for their turn. Therefore, they are not listening to what whoever is speaking has to say. 

More and more, some managers are insisting that laptops are closed while the meeting takes place – at least, while they are speaking! Therefore, the calculator is your only alternative to number crunching during a meeting. 

As well, in a meeting you need to give a fast answer, and this would be difficult with a computer. With a calculator you can do fast and dirty calculations; with a computer, you lose and inordinate amount of time formatting even the most minute calculation. There is a brain switch that allows you to take approximations and shortcuts with a calculator, but impedes all but a perfect mathematical model when you try to do the same thing with Excel!

As conclusion of part one: it is not clear at all that a computer can take all the work a calculator does. Let’s see in part two what happens with the other devices mentioned at the beginning of the article.

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More about the HP41 CL

Is it my ignorance on the subject, or do you share with me the impression that there is a lot going on on the small calculator world? We have mentioned recently 2 different HP15c clones, and the HP41CL, which was the subject of a prior blog. 

Here you have a link to the site. It is not so evident to find it from within Systemyde.com !!

systemyde.com/hp41/

and here is a link to the manual. Please read if you want to commit your old 41C to surgery!

HP41CL manual

Some of the users of this new development are showing us the beauties and virtues of the HP41CL. Geoff Quickfall has made a couple of impressive videos demonstrating the features of this development:

 

 

Here you have a display of calculator speed comparisons between the old and new hp41. The speed difference is impressive!

(If you compare the quality of these videos, they are miles ahead of what you can see elsewhere regarding calculators- Not bad at all for someone starting to record them!!)

 

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