The Contex 30 calculator

The Contex 30 calculator as made by the Brothers Carlsen in Denmark from 1963 till 1971. It was a relatively cheap electric calculator with semi-automatic multiplication and division.
For information on this and other calculators in my collection, please visit my website:
www.jaapsch.net/mechcalc/
0:00 Introduction
0:44 Addition
1:11 Subtraction
1:45 Clearing
2:08 Multiplication
3:09 Repeated multiplication
4:13 Problems
5:19 Division
8:12 Outro

[@GrumpyTim]

I do love the Contex calculators - they really are the most bonkers machines. We have a model 10, which, like yours had the issue with the friction material in the pin matrix disintegrating - I did the rather involved job and replaced the perished foam with new foam. It's not the easiest job because the pin matrix is riveted together, but there was just enough metal to grind a bit away to open the matrix, replace the foam and then re-crimp the metal tabs. The semi automatic multiplication on the 30 is really good, I like that a lot. Favourite of all is the fact you have to write down the digits as you perform a division - I quite fancy adding a 30 to the collection now I've seen yours, cheers Jaap.

[@halloweenengineer6283]

I was waiting to see what button needed to be pressed to make all the numbers show up after the division finished, but nope! Gotta keep a notepad handy there.

[@stephenfreeborn]

Thanks Jaap. Those troublesome Contex pinboards.

[@someonespadre]

That’s an awesome machine.

[@iBlimp]

Thanks a lot for this video 😊😊

[@MattMcIrvin]

The industrial design here is downright peculiar--it looks like it's upside down.