Calculator blog

We have found a unit of Navigation Pac. This time we have found the manual too!

There was a time when many pilots crossed the world with a HP41 with either the navigation pac or their own software. Among them, Geoff Quickfall, Air Canada pilot and the person that knows most about repairing HP calculators in the world!

The pac and manual include the following routines:

• Course planning programs - including the great-circle calculations
• Celestial navigation programs, including all included stars and planets used in the Nautical Almanac.
• Other subroutines including calendar functions, coordinate conversions, etc.

Earlier HP41 full-nuts fixed their processors to the keyboard circuit by means of nuts screwed around the screw posts. The screwing allowed it to press the processor through the zebra to the keyboard circuit. The back side of thecalculator was designed that way: there was a flat side on the underside of the screw posts - see right side of the picture.

Later in production, someone decided that these nuts could ve spared by building a couple of spacers in the back side. These spacers would pass the pressure onto the circuit. You can see them in the left side of the picture. 

The problem with this approach is that it made the tension od the screws fundamental for the proper working of the machine. With the screw posts under tension, there were more and more failures as they broke more often. Also, with the original design, the pressure in the lower part of the case was not required for proper operation - only the upper part needed to be secured.

But the first approach (the "nutted" one) was not free from problems either. You could unscrew it once, to make a repair; but it was very difficult to screw it back on the post. If you had to screw it and unscrew it a couple of times, you broke the screw post completely!

So we decided to replicate the newer back on the older back, by putting aspacer, initially glued to the back side. That had a problem: which size of spacer? there are different thicknesses of circuits, the earlier being thicker than the latter.

Then we realized we did not need to glue it: it was enough to lay it on the circuit, and we could produce it in a variety of thicknesses and we could use whichever fitted best in each case:

A customer of us has a Hand Held Products EPROM programmer in a card reader case for the HP41c family - anyone has information about it? Manuals, etc? Probably it can do functions that some of the Diego Diaz products can; but without a manual, we're lost! 

I spent some time the other day with a Moravia exacutive, talking about the current and future plans regarding HP calculators. As you may already know, from November 1 HP has licensed the calculator business to Royal (for the Americas) and Moravia (for EMEA and Asia). There are many things that cannot be said, but there are several things standing out.

- It seems that the licensees will move faster than HP - there are less layers of bureaucracy, and these guys have been many years in the industry.

- There is a team that will continue the development of the HP Prime - which is a very good calculator.

- The licensees (who have been distributing the HP brand for many years) know the many recent flops of HP product: the quality issues, etc. On the other hand, they are very much business driven - and therefore they have a clear view of the market and are less "romantic" than we are. Their product plans, however, will have "something" for us all.

- The semiconductor scarcity is impacting on the bringing back to market of some models.

As soon as I have a confirmation on the definitive line-up I will come back to you guys with the information!

Now that I am starting to get involved with cases, there is the HP41 case that we need to deal with. 

As you know, the case is bigger than what is needed for the naked HP41 calculator. It was designed so that it could include also the card reader. Apparently HP management thought at the time that everyone would have a card reader. Anyway, they forced the whole customer base to carry a case that was bigger than it needed to be. So be it.

In order for the calculator not to dance within the case, HP filled it with a sponge, foam or whatever with the lenght of the card reade, but much thinner as it was intended to be in the lower part of the case. These sponges got lost in the cases where the user actually had a card reader, or just lost - period.

We are ordering a run of 100 of such sponges, should you want to pad your case as it was intended. The main reason is that when preparing HP41CL machines I cannot afford to send an "incomplete" item.

I will also put them on sale. I have noticed that the yellow sponges are not available in many foam producers, so I will use white color instead. Also higher density than the original. 

Please email to sales@thecalculatorstore.com if you are interested in one!

There is an ongoing discussion in hpmuseum.org about how to repair scratches in HP calculator plastic screens. I have fixed many, and it is clear for me what is the best solution: to use Polywatch - the plastic version (do not get the glass version - it may destroy your screen). 

You apply a drop of this substance on a soft cloth and rub for some time. Remove the white residue with glass cleaner liquid on another tissue - or even a kleenex paper to absorb it. You will see a brilliant screen! This can be used too on you Swatch or Casio watches too.

Ignacio Sánchez asks me why have we started with the Voyager cases, and not with the much more sought-after HP41 cases. These are commanding 30€+ prices in the market - and that's for a 40 year old ugly vinyl case!

The reason was twofold. On one hand, it was a simpler model to produce, and being no leather expert and having to rely on a factory, let's start with a cheap, simple thing before commiting a big amount in tooling (the HP41 case is sibstantially more difficult)

On the other hand, those who have recent Voyagers must be very upset with what they have. There are many cases that are disintegrating. Here below we will show two cases, one that came with an original HP15c LE, and another that came with a recent, Atmel-powered HP12 (while it appears holding a 15c LE inside too!)

The case for the HP12c was notably worse (and I did not treat them wrong at all!!!): I can't wait to change it for something new. This is something you cannot lay on your office table!

If you have an early HP12c model (the three batteries, even the single CR2032 battery type), you have a case that stands the test of time. You are not in this circumstance. You don't need the new leather cases. But if you have one of the HP15C LE or later HP12C units, you will NEED the Calculator Store's leather Voyager case!! We will be receiving the initial batch next week already. See below how they look - a pity that we cannot use the HP logo!!

One belongs to an HP12c, and the other came with a HP18B

We have planned to sell a range of calculator cases for several models - all of them made from Ubrique cow leather. You have seen the tests of the HP12c - which was the easiest of all possible cases. You can see the test below. A question would be which other colors may be interesting. We have seen samples of Burgundy (nice) and Brown (very, very nice). If the original black model sells well, then the brown is next, and the burgundy will follow.

The next model will probably be the Pioneer case, also in leather. It is just slightly longer than the HP12c's, but the same profile - and it also can be used with the newer HP17bII+ (tested with the originals). The factory has already the original samples and could start production if we see that the Voyagers sell well. The original 12c vinyl case had a better texture than the Pioneer cases - although there has been an evolution to a very plasticky version over time - I am thinking about the cases I receive with the HP42s. Also these "plastic" cases break much more often - it is difficult to find a really "complete" unit. However, finding a replacement is quite easy, easier in fact than with the Voyagers: you just need to buy a second hand HP10b off Ebay, and you have it. (you can even drop the calculator later :-)). 

Third in line is a case for the HP41. The original case is one of the ugliest I have seen. What were the HP guys thinking? The shape: I can understand that they thought that everybody would buy the card reader to have it included in the standard case. However, the color was ridiculous! Compare it with any other case built before, even for the humble Spices (hp31, 32, 33, 34, 37): much better!!

Here there are some questions to answer before ordering it, and I would like your input:

• Sized for the calculator or for the calculator + card reader?
• Color: Black? dark Brown? light brown (closest to the original)? Burgundy?

We have received the first tests of leather cases for the Voyager series. The texture is similar to the original - but in good quality leather. The price will be below 20€ each. What do you think?