Calculator blog

Musings and comments about our common interest


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New HP12c: so far so good!

P1040476I have been using the new HP12c for some time already. My main challenge with some HP calculators of late has been that, while they "click" quite well in all cases, there are some odd cases where the click does not register as keystroke. This has happened with the old 12c, 35s and 17bII+. I guess that it has to do with the settings to avoid the rebounds, and that 's a fine line to be walked lightly to avoid double strockes or missing strokes. 

This is of key importance when using the calculator. You need to be confident enough so that you can key numbers without looking at the screen. I have not been able to do that with most of previous HP calculators.

Not with the new model. Key registration has to do with the firmware (unchanged compared to the last version) but also with the quality of the hardware. This edition seem to have sorted out these quality problems and I am getting exactly what I am keying in.

(It also behaves well when reprogramming the unit to another Voyager model)

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Más sobre: HP12c, hp15c
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More comments on the new HP12c

I have been using the new HP12c model that we opened in a previous blog issue. As financial user, I an drawn to the HP19bII back door that is on my desk, but when I travel (quite often), it is too big a calculator to move around, and to lay on a desk. It just uses too much real state. The HP17bII+ is better in that regard, but just slightly. There is something about landscape calculators that make them more suitable for every day work on a real table with a computer and several screens and papers.

Coming to the calculator, it seems to me that they have nailed it. The click of the calculator seems one of the best of the last 30 years, and so far it hasn't missed a stroke. This is very important: we need to be able to key in without looking at the screen, being sure that everything is being recorded as we key. This has not been the case in many previous calculators!

The bezel is real metal, as opposed to the previous model, that seemed plastic looking like metal. This may have the problem that it will receive scratches - but so be it for good quality bezels.

These calculators have also a contrast control - however, it seems to me that there is one step from where it is too little to another just fine. Going darker does not improve.

For the sake of checking, I have entered a HP15c firmware with the programming cable (you need to modify yours, since this one uses the USB protocol) and it works just fine. I just cant wait to see what other calculators can be developed using this hardware base! We can even foresee keyboard overlays to be able to use other calculator models, like HP15c or even HP16c - with the same basic hardware.


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Reprogramming current models

There are two current models that are firmware re-programmable. One is the HP10bII+; the other is the HP12c. 

The HP12c is probably the most attractive to repurpose, because there is already available firmware for several Voyager calculators for several other models.

Both HP11c and HP10c are not too interesting, since why load them when you can load the HP15c - and what's more, there are versions with 3 times more registers or programming steps?

But what about the HP16c? this is a model intended for the Computer Scientist. It has not been reissued unlike the HP15c. And yet it fills a gap of fast operations in different number modes. These can be done with the HP48 family, but it is much more cumbersome than doing it with the HP16c. 

So it has been done:








The problem remains with the lettering. The easy way is to take a photocopy or print out a HP16c picture at full size, and then paste it to the calculator with a transparent tape for packaging. 

We have been considering creating a sillicone cover that would have a better aspect and mechanical feel:



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A comparison between the latest HP12c and the upcoming HP12c

We mentioned a couple of posts ago that there were HP12c units coming our way in a boat. They are slightly different from the previous versions - at least the prototypes we've seen.

(BTW - did I say that they are made in the Philippines, not China?)

The new ones are more "metallic": the lettering in the back looks like metal uncovered by the black paint. Here is the upper one. Notice the additional securing of the battery cover:


The bezel looks real metal, not like the previous one, that looks a little like plastic. The small scratches on the new one are due to heavy use lately:



Is this the template for new coming products? Let's see...

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Más sobre: HP12c, hp15c
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HP15c Manuals


We have included a HP15c Manuals page, where we link to HP15c manuals. There are several languages - including even Japanese!

You can find the page HERE


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HP10bII+ and newest HP12c "on its way"

We have been told by Moravia that the HP10bII+ and the HP12c (of the newest version) are now on their way in a boat from the Philippines.

Compared with the previous HP12c, the newest has the same innards (as shown in the previous blog release), but the bezel looks much more "metal" than the plasticky bezel of the last version. They clearly look better.

The HP12c is many times faster than the HP12c platinum, due to its atmel processor. It is also several times more efficient in consumption than the original HP12c+ and Anniversary - the processors are different and much more evolved when it comes to energy consumption. When I have some time, I will make a comparison.

Due to the programming model, much simpler than the HP15c, it is also significantly faster in simple programs than the Atmel-based HP15c. Go figure! Now, the HP15c has a much wider range of functions, and also much more memory for registers and programs.

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A HP12c's innards

Out of curiosity, I wnted to open one of the latest units of HP12c that I have received. This is a normal unit, made during HP's tenure in the Philippines (I think the actual producer is Kinpo, but I am not sure). Let's see what we find within!

When opening it, you have to remove the 4 feet in the corner. There are 6 screws to unscrew (do you find the sixth?). Trying to open it without unscrewing all will destroy the case.


The sixth screw is below the right battery. Careful!

Once opened, both sides are united by a three cables that carry the power from the batteries. The circuit, on the other hand, is visible in the back of the keyboard. It is very concentrated around the main processor. There are a couple of copper pads that I don't know what they are for. There are also a couple of small springs that are exceedingly easy to lose (This is common to other Voyager calculators of all vintages)



The white band below is an adhesive. again, I don't know what it is for. I have removed it and found nothing to protect below it.

The 6-point connector is a POGO 6-pin connector, but it is connected as a USB interface, as well as a reset device, by shorting specific pins. The problem is that this connector is completely non-standard. There was one produced long ago for the HP15c Limited Edition, but it has a completely different connection schematic. If you have one from that time you can modify it - but it won't work as is with the new calculators.

Is there not another alternative? Yes, it is. In the circuit there are provisions to solder a true USB nano connector. Where? in the right side of the circuit. Here:


I don't know the exact part number that can be connected here. You'd need also to break the case, or have opened each time you want to change the firmware. If you look into, you'll find that there is people around still interested on Voyager firmware mods. You could eventually want to repurpose the calculator for whatever type of calculator or functions. You have, though, the wrong keyboard for it. You would need to consider creating a silicone film with the lettering of whatever you want. 


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HP10c for repair!


The other day I had the opportunity to repair an HP10c calculator. I had not seen such model before! Yes, HP11c and HP15c are better, but the HP10c is the rarest of them all. It was a well used, worn unit, that did not work. I think that the problem had to do with dirt and corrosion, because once cleaned internally with anti-rust fluids it worked just after assembly.

I was able to make it work, though:


When opening it, it was of a more advanced design that I am used to, with a fully covered back that showed a large circuit, instead of the several smallr found in HP15c or old HP12. It also had a flexible circuit I was not used to.:



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Más sobre: HP10c, hp15c
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Happy new 2023

Dear Calculator-lovers,

We wish you a very happy 2023. Hopefully, this year will come with some nice news regarding our hobby - and maybe even new HP-branded calculators! Stay tuned since you will see it here first.

Apart from whatever comes from the HP brand, you will get here at least three new HP calculator related products - specifically produced by us.

Have a nice year and take care.

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Valentín Albillo's Articles


Valentín Albillo is a Spanish pioneer in HP calculators. He has been writing articles about several HP calculators and computers for a long time. He has a soft spot for the HP71b, but he has written articles for most of the HP vintage models.

I had a page linking to his articles in his previous website, but now that that one is down, has hosted Valentín's articles in their website. I just had to update the links to the new site!

You can find here the page that links to all of Valentín's articles:

Valentín Albillo's articles

And here you have one of them, describing, praising and using my preferred calculator: the HP15c:

HP Article VA006 - Long Live the HP-15C.pdf


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