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This manual has been reproduced from a 1976 German publication  

Daro Soemtron 220 

Elektronischer Tischrechenautomat 

Bedienungsanleitung 

69-220-000-5 

We  (

www.soemtron.org

) fully  recognise  the  intellectual  property  rights  of  the  originating  source  and 

will  take  steps  to  remove,  alter  or  further  acknowledge  this  document  if  we  are  notified  of  any 
infringements.  It  has  been  presented  in  good  faith  to  aid  in  understanding  the  inner  workings  of  the 
now vintage Soemtron 22x range of electronic calculators. 

It  has  been  published  by  us  to  disseminate  information  about  the  Soemtron  22x  range  of  electronic 
desk  calculators  manufactured  by  V.E.B.

  (*1)

 

Büromaschinenwerk  Sömmerda,  as  a  project  to  gather 

and  centralise  whatever  information  can  be  found  about  these  increasingly  rare  early  electronic 
calculators. 

If you have or know of any information, books, drawings, circuits, hardware, test equipment (prufgerat) 
or  other  memorabilia  relating  to  the  Soemtron  220,  221,  222  or  224  calculators,  their  trade  names  - 
Daro  or  Soemtron,  manufactured  by  -  V.E.B.  Büromaschinenwerk  Sömmerda,  please  email  us  at  - 

[email protected]

 

This document has been scanned from an original book, processed through an on-line OCR software 
package  to  regenerate  the  original  German  text  and  then  automatically  translated  to  English  and 
imported into Microsoft Word. Layout has been duplicated in line with the original document as much 
as possible to retain the flow of the original document. Drawings, circuits and photographs are scans 
from the original document. 

With  this  effort  in  mind  some  of  the  syntax  in  the  document  may  be  a  little  strange.  Some  portions 
have  been reworked to  be more readable English  text but there is obviously  more to be  done. If  you 
can  help  with  this,  or  indeed  have  any  helpful  information  or  comments,  please  email  us  at  - 

[email protected]

 

Please use, and hopefully enjoy, this in information in the spirit in 

which we undertook to generate it - as an information source for an 

interesting piece of early calculator history before the advent of 

modern electronics, in the days when “hands on” engineers thought 

through the problems and challenges of designing equipment with 

little resources, to produce the best end product they could.

 

 

August   2019 -   

www.soemtron.org 

    -   

[email protected]

                              Revised 21/8/2019 

Summary of Contents for Soemtron 220

Page 1: ...maschinenwerk Sömmerda please email us at mike soemtron org This document has been scanned from an original book processed through an on line OCR software package to regenerate the original German text and then automatically translated to English and imported into Microsoft Word Layout has been duplicated in line with the original document as much as possible to retain the flow of the original doc...

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Page 4: ...ies 11 4 7 Decimal points 11 4 8 Constant factors 12 4 9 Correction 12 5 Input and output capacity 13 6 Calculation examples 14 1 Addition 14 2 Subtraction 14 3 Addition and subtraction in 3 stores with netting 14 4 Multiplication with different Decimal points 15 5 Multiplication with different Decimal points 16 6 Constant factor average calculation 2 memory 16 7 Multiplication by a parenthetical ...

Page 5: ...th constant factor 2 memory 21 21 Conversion of the English currency 22 22 Insurance calculations insurance 22 23 Weight calculation 23 24 Subtraction of two Quotients 23 25 Calculation of the cutting speed 24 26 Amortization Schedule 25 27 Invoice control with 3 save 26 28 Series Development Minus Division 28 29 Labour Statistics 29 30 Square root calculation after the iteration 31 31 Cubic root ...

Page 6: ...y can be achieved The electronic desktop calculator Soemtron 220 solves the most varied tasks at all levels of commercial and scientific knowledge technical and technical sector The electronic desktop calculator comes in 2 variants as type 220 1 with a memory and as type 220 3 with 3 memories manufactured The calculation functions are the same for both models It accounts for only the type 220 1 th...

Page 7: ...te key 3 Correction key 4 Decimal point key 5 Numeric Keypad 6 Sign key 7 Multiplication key 8 Addition Key 9 Result key 10 Subtraction 11 Division key 12 Exponentiation 13 Memory Addition 14 Memory subtraction 15 Memory recall without deletion 16 Memory recall with deletion 6 ...

Page 8: ...a secure maintenance is guaranteed The electronic desktop computer consists of the following modules Keyboard The keyboard is arranged clearly and within reach It is divided in 3 key groups Left key group Numeric keypad 0 9 Digits Decimal point dial Lö Delete key C Correction key Decimal point key Middle button group Function keys Enter a negative number Xn Exponentiation X Multiplication Division...

Page 9: ...Decimal point is indicated by a red dot in the display unit shown COMPUTATION UNIT The computing unit assembly comprises all the electronics of the machine including the ferrite core memory and the control system of the machine Display unit POWER ADAPTER The power supply generates the necessary voltages of the machine Form and colour match the modern line Dimensions and mass make an effortless job...

Page 10: ...cated to recognize from the outside through the breather For commissioning the computer must be connected to the mains using the protective earthing cord provided after checking the setting After pressing the switch on the lower right side of the Cover is the operational readiness of the machine by a red indicator lamp is displayed in the display unit Before the start of the calculation to press t...

Page 11: ...n The subtrahends are entered into the calculator by In the memory I II III Memory recall without deletion I II III Memory recall with deletion I II III 4 3 Multiplication The multiplicand is entered by the X key Pressing the key is used to transfer the multiplier to the calculator the multiplication is triggered and the product is displayed If a sum or a difference in the arithmetic unit has been...

Page 12: ...values from one memory to another with the correct sign Example Memory I then Memory II By pressing the button I II III the corresponding memory is called up and deleted at the same time The value in the calculator can be processed further Pressing the Delete Lö key does not clear the memories Should the memory contents be checked during a calculation process without the last displayed value eg If...

Page 13: ... the memory or be returned from the memory The results products and Quotient are automatically rounded in the last place IE from paragraph 5 is rounded up The decimal position must be maintained during the computation process you may have added values to the memory or be returned from the memories Example Decimal point position 6 1 000000 6 000000 0 166667 Decimal point position 3 2 58 X 3 01 7 76...

Page 14: ...9 999 999 X 99 999 999 999 999 999 999 890 000 Division of whole numbers The digits of the dividend and the divisor to be entered in the division can be a maximum of 15 digits the quotient always being smaller Example 999 999 999 999 999 999 999 999 999 999 1 Division of decimal places When dividing numbers with decimal places make sure that the quotient increases if the divisor is less than one E...

Page 15: ...k through Sequence of the calculation Function key Display 1 Decimal point position 0 2 Enter 461 461 3 Enter 207 207 4 254 Example 397 98 612 17 214 19 Walk through Sequence of the calculation Function key Display 1 Decimal point position 2 2 Enter 397 98 397 98 3 Enter 612 17 612 17 4 214 19 3 Addition and subtraction in 3 stores with nett balance Example I II III 467 533 650 890 123 2400 1357 6...

Page 16: ...ll III 1750 14 I 1750 15 Recall I 1049 4 Multiplication with different decimal points Example a 1234 56 X 17 5671 21 687 639 0 b 5 678 123 X 0 000 11 356 c 1 1 X 9576 5432 10 364 1975 Walk through Sequence of the calculation Function key Display a 1 Decimal point position 4 2 Enter 1234 56 X 1 234 560 0 3 Enter 17 567 1 21 687 639 0 b 1 Decimal point position 3 2 Enter 5678 123 X 5 678 123 3 Enter...

Page 17: ...2 63 115 50 Walk through Sequence of the calculation Function key Display 1 Clear the memory I II 2 Decimal point position 2 X 22 00 4 Enter 2 7 I 2 70 5 Xn 59 40 6 II 59 40 7 Enter 2 55 I 2 55 8 Xn 56 10 9 II 56 10 10 Recall I 5 25 11 5 25 12 Enter 2 2 63 13 Recall II 115 50 7 Multiplication by a parenthesized expression Example 958 X 17 12 4 3 0 030 10 911 620 Walk through Sequence of the calcul...

Page 18: ...calculation Function key Display 1 Decimal point position 0 2 Enter 225 225 3 Enter 5 45 10 Division with constant dividend Example 22 33 44 22 101 52 22 33 44 23 97 11 22 33 44 24 93 06 Walk through Sequence of the calculation Function key Display 1 Clear the memory I 2 Decimal point position 2 3 Enter 2233 44 I 2233 44 4 2233 44 5 Enter 22 101 52 6 Recall I 2233 44 7 2233 44 8 Enter 23 97 11 9 R...

Page 19: ... 000 8 46 164 12 Division with a parenthetical expression Example 750 47 623 710 21 304 1 1 653 Walk through Sequence of the calculation Function key Display 1 Decimal point position 3 2 Enter 750 750 000 3 Enter 47 623 47 623 4 Enter 710 21 710 210 5 Enter 304 1 304 100 6 1 653 13 Percentage searched Example 86 work pieces 100 54 work pieces 100 X 54 62 8 86 Walk through Sequence of the calculati...

Page 20: ...percentage was the standard exceeded Example 54 work pieces 100 68 work pieces 100 X 68 125 9 54 Walk through Sequence of the calculation Function key Display 1 Decimal point position 1 2 Enter 6800 6800 0 3 Enter 54 125 9 16 Reduced value B produces 120 work pieces per day which corresponds to a standard compliance of 130 What is the norm Example 130 120 work pieces 100 120 X 100 92 work pieces 1...

Page 21: ...X 106 667 Walk through Sequence of the calculation Function key Display 1 Decimal point position 3 2 Enter 1695 X 1 695 000 3 Enter 45 76 275 000 4 76 275 000 5 Enter 100 762 750 6 762 750 7 Enter 106 667 7 151 19 Distribution task 3 memories A has been allocated a budget of 150 375 50 m The amount is broken down and at the same time the percentage of the loan is calculated Example B 5 640 00 150 ...

Page 22: ...ent of memory III multiply the displayed values by 100 20 Wage settlement with a consonant factor 2 storages In the post calculation the per hundred minute rates of each individual operation must be multiplied by the wage group factor become Example Wage group Factor Min Wage 3 2 23 230 5 13 3 2 23 145 3 23 2 23 X 375 3 36 Walk through Sequence of the calculation Function key Display 1 Clear the m...

Page 23: ...9 I 0 040 2 10 Recall I 25 446 2 11 X 25 446 2 12 Enter 9 85 250 645 1 250 65 M 25 8 11 22 Insurance calculation insurance premium calculation How much 0 00 is the premium if A has insured his house at 95000 00 M his furniture at 13000 00 M and his carriage at 11500 00 M The annual premium is 334 60 M Insurance 95 000 13 000 11 500 119 500 M 334 60 X 1000 2 8 0 00 119 500 Walk through Sequence of ...

Page 24: ...3 Enter 2 0 119 000 4 X 0 190 000 5 0 036 100 6 X 0 036 100 7 Enter 3 14 0 113 354 8 X 0 113 354 9 Enter 3 0 340 062 10 X 0 340 062 11 Enter 0 72 0 244 845 The result must then be multiplied by 1000 since it is kg 24 Subtraction of two quotients 2 604 0 342 Example 1 801 1 315 1 910 Walk through Sequence of the calculation Function key Display 1 Clear the memory I 2 Decimal point position 3 3 Ente...

Page 25: ...ll I 11 25 Technical calculation calculation of the cutting speed The cutting speed is always given in m min grind m sec Example v Speed 141 3 n speed rpm rev sec 300 d diameter of the rotary part 150 d X 3 14 X n 1000 X v 1000 X v v n d 1000 d X 3 14 3 14 X n 150 X 3 14 X 300 1000 X 141 3 1000 X 141 3 v n d 1000 150 X 3 14 3 14 X 300 Walk through Sequence of the calculation Function key Display 1...

Page 26: ...call I 3 14 19 942 00 20 942 00 21 Recall II 141 300 00 22 141 300 00 23 150 00 26 Repayment schedule Example With an initial capital of 45 000 00 M an annual interest rate of 8 50 and a 4 repayment the following semi annual repayment based payment scheme Constant multiplier is the semi annual interest rate of 4 25 and repayment of 1 50 Capital Figures Repayment Annuity Time 45 000 00 1 912 50 675...

Page 27: ...is again calculated by multiplication by the constant factor 4 25 Walk through Sequence of the calculation Function key Display 1 Clear the memory I II III 2 Decimal point position 2 3 Enter 45 000 II 45 000 00 4 X 45 000 00 5 Enter 4 25 I 4 25 6 191 250 00 7 191 250 00 8 Enter 100 1 912 50 9 1 912 50 10 Enter 2 587 5 III 2 587 50 11 2 587 50 12 675 00 13 II 675 00 14 Recall II 44 325 00 15 X 44 3...

Page 28: ...ignation price 12 345 3 52 21 3 452 00 6 169 415 10 23 456 3 3 25 32 419 00 4 101 147 28 34 567 3 112 00 2 359 00 5 250 997 60 Signing Tare Price Designation Value 521 560 06 Packing Packaging 1 275 00 material Aggregate value 522 835 06 Sales 8 41 826 80 tax I Sales 41 826 80 tax II 30 12 548 04 Invoice sum 577 209 90 Walk through Sequence of the calculation Function key Display 1 Clear the memor...

Page 29: ... 00 23 Enter 0 05 13 210 40 24 I 13 210 40 25 Recall I 250 997 60 26 II 250 997 50 27 Recall I 521 560 06 28 Enter 1 275 II 1 275 00 29 Recall II 522 835 06 30 X 522 835 06 31 Enter 0 08 41 826 60 32 II 41 820 80 33 X 41 526 80 34 Enter 0 30 12 548 04 35 II 12 540 04 36 Abfu1 II 577 209 90 37 Enter 521 560 06 X 521 560 06 38 Ein1asten 0 05 26 075 00 39 II 26 078 00 40 Recall II 551 131 90 28 Serie...

Page 30: ...II 1 000 000 17 1 000 000 18 Enter 9 0 111 111 19 I 0 111 111 20 Recall II 1 000 000 21 1 000 000 22 Enter 11 0 090 909 23 I 0 090 909 24 Recall I 0 744 012 29 Labour statistics In one establishment the following figures are available Wage group Wages Workforce Wages Workforce L0 Z0 L1 Z1 1 300 00 200 330 00 200 2 330 00 300 380 00 400 3 370 00 400 440 00 500 900 1 100 For statistical purposes the...

Page 31: ...er 900 1 22 5 Enter 330 X 330 00 6 Enter 200 66 000 00 7 I 66 000 00 8 Enter 380 X 380 00 9 Enter 400 152 000 00 10 I 152 000 00 11 Enter 440 X 440 00 12 Enter 500 220 000 00 13 I 220 000 00 14 Enter 300 X 300 00 15 Enter 200 60 000 00 16 II 60 000 00 17 Enter 330 X 330 00 18 Enter 300 99 000 00 19 II 99 000 00 20 Enter 370 X 370 00 21 Enter 400 148 000 00 22 II 148 000 00 23 Recall I 438 000 00 2...

Page 32: ...result is already obtained with the approximate approximation To increase the accuracy of the result It is necessary to count as many decimals as possible Therefore the Decimal point position 6 has been selected in the following examples 2______ Example 630 01 The Radikand is divided from the left to the left in groups of two digits In this example there are two groups 2_________ 6 30 01 The numbe...

Page 33: ...0 010 000 4 630 010 000 5 Enter 23 II 23 000 000 6 27 391 739 7 II 27 391 739 8 Recall II 50 391 739 9 50 391 739 10 Enter 2 25 195 870 11 II 25 195 370 12 Abfu1 I 630 010 000 13 630 010 000 14 Ab u1 II 25 195 870 15 25 004 495 16 II 25 004 495 17 Abru1 II 50 200 365 18 50 200 365 19 Enter 2 25 100 103 20 II 25 100 153 21 Recall I 630 010 000 22 630 010 000 23 Recall II 25 100 183 24 25 099 817 25...

Page 34: ..._ 2 Triplets and therefore Example 2 847 39 2 Ask before the Decimal point 3_________ Example 279 489 Here is a group of three so that the number of digits before the decimal point is 1 digit The cube root of 279 is about 6 5 Now you can start with the calculation according to the iteration formula 1 279 43 6 5 6 5 6 538 304 1st Approximation 3 6 5 2 1 279 48 6 538 304 6 538 3042 6 538 080 2nd App...

Page 35: ... Enter 3 0 030 104 17 I 0 038 304 18 Recall I 6 538 304 19 X 6 538 304 20 Xn 42 749 419 21 42 749 419 22 Recall II 279 480 000 23 279 480 000 24 6 537 633 25 6 537 633 26 Recall I 6 538 304 27 6 538 304 28 0 000 671 29 0 000 671 30 Enter 3 0 000 224 31 I 0 000 224 32 Recall I 6 538 080 33 Sample X 6 538 030 34 Xn 42 746 490 35 Xn 279 479 971 34 ...

Page 36: ...voltage 220 V I0 50Hz 15 110 V I0 50Hz 15 4 Input power 50 VA 5 Clock speed 25 kHz 6 Capacity Input Display 15 digits Calculation register plus Memory sign 7 Computing time Addition 5 ms Subtraction Multiplication average 0 5 s Division 8 Number of calculation 3 Calculation register and storage registers 1 3 storage memories 9 Type of entry Number keys 10 Type of display Numeric display tubes 11 F...

Page 37: ...operator Necessary repairs can only be done by specially qualified technicians For the handling of electrical devices reference is made to the regulations of the respective country In the case of extremely unfavorable operational peculiarities the operator still has to work out the operational and fire protection instructions according to the national legal regulations Operating instructions for m...

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