| Type name / number: |
Ivrea Tetractys (Calculator and listing Machine) Part of the MC24 series |
| Production / SN: |
2D 047065 |
| Calculating principle: |
Rocking Segment with Ten key keyboard |
| Calculating functions: |
All four basic operations of arithmetic, including automatic multiply and divide |
| Input accuracy |
12 digits |
| Calculating accuracy: |
13 digits |
| Extra's: |
The machine has two calculators (Often described as 2x Multi Summa 24) |
| Designer: |
Two designers are seen credited:
- Mr. Marcello Nizzoli for the body-case design.
- Mr. Natale Capellaro (several pattens) for the mechanisms:
|
| Production year: |
From 1956 on to early 1970. ( average ~50 units/day. In total 6 Million produced of the series MC24 machines).
My machine produced in ~1964; price in 1964:
325.000 lire an FIAT 500 cost 465.000 lire at those days |
| Case material: |
Aluminium |
| Weight: |
20 Kg |
| External links: |
History |
| Previous owner: |
Mr. A. Moser, 30855 Langenhagen, Niedersachsen, Germany |
Cosmetic imperfections:
(I
accuse no one) |
Some oxidation under the paint, but in general in a perfect shape. |
| Date of receiving: |
2013-07-25 (eBay) |
| Machine story: |
2014-04-29
First mechanical checks showed a clean machine internally. Electrical shorts with mains. Need further detail electrical check which component(s) is(are) defect.
2014-05-14
It was not an electrical short with the mains (220V) but a short to the earthed.
I decided to replace the complete motor unit with one of a spare of a Multi summa 24 (which was mechanical completely blocked and not reparable.
One alternative was to replace some components of the electrical network with new separate components, but these components are in sight and the new ones are then not as nice packed (combined) as the originals.
Demounted the motor and replaced it with the spare one.
Tested the new situation and the clutch was activated at the end of the calculation cycle. Turning it manual on the main axis. Obvious hardened oil on the main axis but with penetrating oil slowly it became nice smooth turning. The motor test showed that not all digits react well. Here and there oiled and adding was correct at all digits en with all numbers. Multiplication was successfully executed as well. Nice with the "=" , en separate "*" (or sub total) key. As the Olympia RAS 12 52 has, the multiply result is available for further calculation and the totals are available still).
Need to know first the extra functionality of the different other key's before further testing.
2014-05-15
Division test is as well
passed, please see the pictures.
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