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Calculator blog

Musings and comments about our common interest


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Different colors for the Voyager true leather cases

We have just ordered from our supplier two new more colors for the leather cases. 

Up to now, we have been selling the black case. I think that the quality is really excellent and the first batch is nearly gone. We have ordered a second batch - and also the two new colors: Brown and Bordeaux (which would be called Burgundy elsewhere). The pictures of the two colors that I have do not make justice to the real aspect - I will post them once the first batch has arrived.


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The HP12c "Gold" is back !!!


We have found a stack of English language HP12c - the one with gold color, RPN only, and much faster than the platinum, with a ARM processor! (what was called at the time HP12c+) Nicer screen too.

We will offer it with and without leather case - for 89.90€ and 77.00€ respectively. (all units come with the standard fake-leather PE case anyway). Order before units disappear !!


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Good things coming next year!


Next year is the 50th anniversary of the seminal HP35 calculator - the unit that started it all .

It is quite likely that there will be "something" from the licencees to commemorate this fact. From what I understand and heard, I think we all are going to like it!

(it will not be a reissue of the HP35 - which is a beautiful unit but not a practical calculator to be released!)

Let's be ambitious!

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More about the leather case for voyagers

I have sent the first lot of Voyager cases to customers. Trust me: the look wonderful ,and have the leather texture of the original vinyl cases!!



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Navigation Pac

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.


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Spaces for repair

tipops_de_traserasEarlier 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:


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HHP Eprom programmer in card reader 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! 




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News from Moravia


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!

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HP41c case sponges


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 if you are interested in one!

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Scratches in HP calculator screens


There is an ongoing discussion in 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.




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