Bolek and Lolek from Wroclaw

In my last article on retro equipment, I told you about a pocket calculator manufactured at the Unitra Eltra plant in Bydgoszcz. This time we will also take a closer look at a pocket design, or even several such devices from the times of centrally planned economy, with the difference that these will be calculators signed with the logo of Wroclaw Elwro.

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Bolek and Lolek calculators

Polish pocket calculators are primarily associated with the Brda series produced by Bydgoszcz-based Unitra Eltra. However, it should be remembered that Elwro also had its episode with pocket calculator designs. We can actually distinguish three calculators with proud names – Bolek, Lolek and Jacek. There were also devices referred to by a specific number, a designation, but the question of names in the case of Elwro is not so simple and we will get to it later. Today, however, we will look at the Bolek and Lolek calculators and one rather mysterious design. The genesis of the name Bolek and Lolek hardly needs to be introduced to anyone. It is obvious that it was taken from the animation of the same name created by the Drawing Film Studio of Bielsko-Biała.

Both calculators are very similar to each other, placed in identical housings. The only differences are the colors of the buttons, the markings, as well as the model name itself located in the upper left corner. The power supply is also identical, the calculators can draw power from a 9V battery, enough for about 2.5 hours of operation, or a dedicated power adapter. Bolek and Lolek appeared on the market in 1977, by design the former was a simple design, while the latter was an advanced one. Interestingly, Lolek was one of the first Polish scientific pocket calculators.

The working panel otherwise the keyboard is a fairly successful design, but a lot depends on the intensity of its use. In the Lolk it works perfectly and there is nothing to complain about, but in the Bolk it is no longer necessarily so. The keys have to be pressed a little harder, and the result can be a doubled or tripled character on the display.

Bolek and Lolek calculators

With the markings it is similar to the keyboard. In the Lolk they have been preserved brilliantly, while in the Block, however, one can see a trace of time. Interestingly, there is an opinion on the Internet that the paint used to print the markings on the more advanced design has a different chemical composition, so that the markings are still in great condition. Unfortunately, I have not been able to confirm this information in any way, but there may be something to it, because as far back as I can remember all the simpler designs have slightly rubbed markings, while those with more functionality do not.

A certain myth is the belief that Bolek always had markings in blue and Lolek in orange. Yes, blue was standard on Bolek and the others were not, but Lolek appeared in both blue and orange versions. Although it was the latter that was much more popular.

Elwro Bolek

Bolek nameplate

I’ve mentioned the Elwro product designations before, and it’s time to make this topic a little clearer. Two simple calculator models were designed in Breslau: the 440 and the 441. In theory, the name Bolek began to be used only after the 441 model was introduced, also 441 = Bolek. 440 refers to earlier designs or prototypes, and we can also find such. These are calculators that have the Elwro Model 440 designation in place of the Bolek inscription. However, as is the case with devices of those years, theory, theory and life life. As you can see for yourself, my copy of Bolek has the designation 440 on the nameplate. Also, it is assumed that if there is a Bolek inscription on the front, it is a Bolek, regardless of the number on the bottom. On the other hand, any unit with a different name on the front is a 440 model.

The interior of the calculator after opening the case

What would my material about the calculator be without a look inside, also welcome. The two parts of the case are connected by latches that hold quite tightly, you need to open it carefully. After opening it, we can see the underside of the motherboard and the cables leading to it from the keyboard PCB, the battery space and the on/off switch.

On the front Bolek, on the bottom type 440, and on the motherboard 441. Quite a mess they had in this Elwro😄. You can also notice the inaccurate distribution of soldermask.

Full interior of the device

To get further you need to unsolder the wires from the battery contacts and remove the switch. The motherboard itself is held on by plastic latches, after bending them off we can see the other side.

Bolk's main processor

The brain of the Bolk is the MPS 7545 chip made by MOS Technology. This design is quite successful and has been successfully used in many calculators: APF 21, APF 23, COMMODORE 9R23, COMMODORE 9R25, CONDATA 2000-7 (version 2). Also pay attention to the last line and the 004 designation, as it is quite important. The MPS 7545 chip could come in versions 001, 002, 003, 004 and 005, but only the last two supported multiplexing of the seven-segment display. Other than that, the design is quite classic – four basic functions, primes, inverse and memory support.

Display controller

Hidden underneath the display was the chip associated with it – DS8872N, a current amplifier that allows controlling the display. This chip was also manufactured in the West, precisely at the National Semiconductor (now Texas Instruments) factory. Sometimes a Polish copy can be found here – CEMI UCY74549.

The display in its full glory

Contact with the outside world is possible thanks to a nine-position LED display. This type of design was also used in the Brda series of calculators. Each digit consists of seven segments, while each segment is another four sub-segments. In the Bolk, only eight digits can display numbers, with the last nine used to show special characters.

Display manufactured by National Semiconductor
The problem of "negative zero"

Bolek, like other calculators from the 70′s, suffers from the problem of negative zero. If we perform the operation 1-2+1 we get the result -0. Unfortunately, this problem is a fairly common design flaw of the processors in calculators of those years. Interestingly, this problem does not occur in the Lolk.

Elwro Lolek

Lolek nameplate

As with the Bolk, let’s clarify the issue of designations. Here, too, there are two models, 480 and 481, but fortunately both are Lolks. No earlier versions appeared on the market with a designation of only “type 480.”

We get to the interior identically, the case is held on by snaps
Here the markings match, although the soldermask is also laid rather sloppily
Interior of the calculator

The procedure for moving on looks analogous, unhooking the wires from the battery cage, removing the switch and sliding the motherboard out of the latches.

Calculator brain

Since the calculator is more advanced then the processor must be bigger too. Here we have the MPS 7529 version 013 also made by MOS Technology. This chip was also the brain of calculators such as ARISTO M76 (version 1), ARISTO Unilog S, VANGUARD 25PA, PRIVILEG SR58DNC, RADIO SHACK EC480, and UNITRA ELTRA BRDA14S. The MPS 7529 comes from the same series of chips designed for use in calculators as the MPS 7545 presented a moment earlier, except that here support for more functions has been added.

And under the display, the same DS8872N chip
The display is also an identical design to the Bolk, but here manufactured at Poland's CEMI
Energy saving mode

Thanks to the use of a more powerful processor, in addition to more functions, we also gained power saving. When the calculator is not in use, it extinguishes all digits and lights up only one LED segment.

And you, sir, who are you?

Bolek, Lolek and a third mysterious gentleman

Part of my collection is yet another rather puzzling calculator. The casing here is identical to that of the Bolko and Lolko, but a bit strange primarily because of the logo, which was not even present in the 480 version. The attention is also drawn to the rather heavily saturated color of the buttons. It should also be mentioned that the device has no nameplate.

From the markings on the PCB, one might suspect that it is a full-fledged Bolek
Unlabeled processor

Also mysterious is the processor, it is definitely an MPS… version 004. Probably MPS 7545 the same as in the Bolk, but it is puzzling that someone apparently tried to wipe off the chip designation.

Display driver

The display controller the same DS8872N, but manufactured earlier than those in the Bolk and Lolk. This can be seen in National Semiconductor’s early log of two pictograms.

Display manufactured at National Semiconductor facilities
Display during operation

What this calculator really is, it’s hard to say. I bought it once for a pittance just because of the strange looking case. Rather, it is definitely a Bolek, just in some strange/unique version. I would rule out early prototypes of the 480 model here because of the designation on the board – 481. The lack of markings on the keyboard, plus the blurred processor designation, all puzzling. Personally, I’m inclined to the theory that this could be any of the early versions/prototypes of the 481 model, or the book Bolko. Who knows, maybe this copy once belonged to one of Elwro’s employees, and after time it came to me, well I’ll probably never know.

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