Elektronika B3-25A

Is this a B3-25A?

...Or is it?

This one is very interesting, and there's a bit of a mystery behind it! At first it looks pretty ordinary, but there are several discrepancies which point to the rather strange hybrid status of this particular machine.

It is a copy of a Rockwell -- the keys are even shaped the same, with the slight concavity and slant. However the case is different. The calculator doesn't have scientific notation, and so is limited in numeric range to 8 digits. For a scientific calculator, this is quite a limitation. You can't, for example, calculate 10⁸, as you will get an overflow! Once an overflow occurs, C will clear the error flag but leave the out-of-range result in the display, C again will return to 0.

This fabulous machine has the most "alien" looking battery compartment you are ever likely to see! I hooked this up to a transformer generating 8V and took my chances... and it lit up! My Soviet friend tells me that you can't buy batteries like it in Russia, either. Recently I have obtained some batteries (the B3-34 uses the same size), and these can be seen on the power page.

Sergei Frolov contacted me and said that he thought my B3-25A was, in fact, a mis-badged B3-18A. In fact, Kenton Green also indicated this was probable, a long time ago. He wrote...

By the way, I have a slight suspicion that your B3-25A may be mislabeled, or at least that there was another fundamentally different style: at least one of my sources gives information about a b3-25A that is different from yours, for example listing no scientific features, and different dimensions. Also, your B3-25A is the first time I had ever heard of two Russian scientific calculators with the identical same features/key-layout have different B3-xx numbers (B3-18 and B3-25).

At first I was dubious, but Sergei's logic is persuasive. Have a look at the above two diagrams. The one on the left is from the manual for my B3-25A, and the one on the right (supplied by Sergei) is also of a B3-25A. Note that both of these diagrams show a total absence of an F key (conspicuous by its absence), and also a complete absence of any shifted-functions. In fact, the manual for my B3-25A makes absolutely no mention of the shifted functions so obvious on the faceplate. However, if you look carefully at the picture of the front cover of the manual, you can see that there is a key (though unlabeled!) where the F key should be. So, what gives?

The B3-18A is similar to this machine. Remarkably similar. In fact, its an exact copy with different badging. So, in theory, this B3-25A I have could be a mis-badged B3-18A. But that's hardly convincing. Sergei has some interesting calculator documentation, leaflets, and advertising. This material indicates that the b3-25a and b3-18a share the same circuitry. I will let Sergei finish the argument, in his own words... In the directory is told, that these two calculators are made on the same microcircuit. By simple completion the calculator B3-25A is altered in B3-18A. Such updating could make, for example, in workshop on repair calculators. As cost of the first issues b3-18A was very great, that, probably, the designers did not become to develop the new simple calculator, and by removing one key, have made simple variant under the cheaper price. Pay attention to presence in the instruction to the calculator of the description of functions, which are in B3-18A above keys. The calculator b3-18a, most likely, was made at a military factory. This implies, that the quality surveillance was very high. Discrepancies in the documentation (especially absence the description of the important functions) is inadmissible. So, we have a calculator which looks totally different than two independent sources suggest (the manual in my possession, and Sergei's documentation). We have a second calculator which we know shares circuitry with this model. We have a manual for this calculator which strangely has no mention of the function key or shifted functions. And we have obviously identical functionality with the b3-18A and this particular B3-25A. What would be the sense in creating two model numbers for identical calculators? Not much. I am leaning towards agreement with Sergei and Kenton that this calculator is mislabeled. This calculator has the same internal IC (IP12) as the B3-18M, but not the B3-18A. Therefore, it is probably either a B3-18M badged as a B3-25A, or a B3-25A modified to B3-18M through the addition of a faceplate upgrade and rebadging. Of course, we must wait for another example of the B3-25A to show up - if the theory is correct, it will look like the two diagrams (no F key). That will be interesting, I'm itching to find out, already!

© Sergei Frolov The real B3-25A

Lucky Dog!

Just recently, Sergei found another B3-25A, and you can see its picture here. Sergei and Kenton were right; my B3-25A is an impostor! The true B3-25A has no shifted functions (indeed, no F key).

The switch at the top right says "Charge 1" and "Charge 2", implying that this machine was capable of recharging its batteries when connected to its transformer.