Soemtron 220

Soemtron 220

The Soemtron 220 (a.k.a ETR220) is an East German made early pre-IC era electronic calculator with a distinguishable magnetic-core memory consisting of 6 x 16 digit registers, for a total of 384 bits or 48 bytes of memory. These pre-microprocessor era calculators were manufactured during 1966-1977 in the town of Sömmerda, near Erfurt in Thuringia, East Germany.

The processing logic of the Soemtron 220 calculator is based on diode-transistor logic (DTL), built entirely with discrete-components, consisting of PNP germanium transistors (Hitachi 2SB77) coupled with resistors, capacitors and diodes. (Source: soemtron.org)

The machine has many different date codes found on the boards (39/69, 03/71, 37/75, Juli 1974), the latest found to be 37/75, which is derived here as a nearest to the real production date - 37. week of 1975.

This machine comes from the southern Estonian town of Viljandi, from the local machine computing station (Viljandi Rajooni Masinaarvutusjaam) - a typical Soviet-era governmental institution that provided analytics and statistics services for the local institutions, collective farms, factories, etc.

After writing off due to the arrival of the new era of electronic computers in the beginning of the 1980s, the machine was brought home by the employee as memorabilia. It was acquired from there at the beginning of 2024. The machine has an inventory number 6 painted on the side of the case with white paint. On the back it has an export label: Böromachinenexport GmbH, Berlin, DDR.

As a characteristic feature, this machine has a repaired plus-key on the keyboard. The original key switch spring has been replaced in some point with a non-original shorter spring, causing it to be lower than other keys on the keyboard. To "fix" this issue, a transparent plexiglass piece has been glued on to the key, bringing it to the same level as other keys - an ergonomic improvement probably made by a local handyman. The whole reason for this fix would be the lack of original spare parts in the Soviet supply system.

Condition: faulty (leaked capacitors on the power supply board). Complete with the Soemtron-type socket power cord.

Weight: 15 kg
Dimensions: 45 x 38 x 18 cm

Year of manufacture: 1975

Serial №: 51250

Manufacturer:
	VEB Büromaschinenwerk Sömmerda Erfurt in Thuringia, East Germany

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Soemtron 220

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Did you know ...?
The city of Sömmerda, located in Thüringen, one of Germany's 16 states, is known for its long history of manufacturing various office machines. The history of Rheinmetall goes back to 1889, when the entrepreneur Heinrich Ehrhardt founded the Rheinische Metallwaaren- und Maschinenfabrik AG (Rheinmetall) an started the manufacture of ammunition. In 1901 the company took over Munitions- und Waffenfabrik AG in Sömmerda which initialised rapid growth of weapons manufacturing for the German Reich.

After the World War I, the treaty of Versailles restricted all weapons and ammunition manufacturing. The company looked for a new field of business and turned it's focus to the office machines manufacturing. In 1920, the first Rheinmetall typewriter was brought into the markets. In 1922, production of the first series mechanical calculators, the model R, was started in Sömmerda factory. Various typewriters and calculating machines were manufactured under the Rheinmetall brand name.

Aftrer World War II, Sömmerda found itself in East Germany (German Democratic Republic). The Rheinmetall factory was nationalized by the Soviet occupation regime and turned into state-owned combine "Rheinmetall-Borsig SAG" which was initially subordinate to the Soviet parent company Schetmash in Kursk, USSR. In 1960, the brand name Supermetall was introduced, and shortly after that, in 1962, all production was combined under the Soemtron brand name in "VEB Büromaschinenwerk Sömmerda".

After World War II, Germanies were obliged to pay war reparations to the Allies. One of many war reparations was also to manufacture typewriters and calculating machines for the USSR. This was carried out by the Rheinmetall during 1941-1952. Even after the reparations were fulfilled, USSR stayed the main export market for Soemtron. The most numerous models exported into the USSR were calculators KEL II c and SAR II c, which were marketed in the USSR as ВМП-2 and ВММ-2.
Source: Rechnerlexikon :: Rheinmetall_KEL_IIc