Presentation and question about calculators long term storage at low temperature

[Alevin]

Dear all.

This is my frist post. Let me introduce myself.

My name is Ricardo Aliod , mechanical engineering Professor at “Escuela Politécnica Superior de Huesca”, which belongs to Zaragoza University, in Spain.

I am committed to organize a “home made” small educative exhibition , about scientific pocket calculator history. Its under preparation at it is programmed to start next September.

I would like to post here two initial questions:


1) Frist one, related to exhibition. Mainly the items that will be exhibited come from donations (credited), but still we have a small budget for some acquisition of famous items like HP75B,(and other non HP calculators). If you could give us some help to find it apart form Ebay (since we have scrutinized there and we know what is offered ) at a reasonable price, please, send me a pm.

2) The second and main question is about calculators conservation and long term storage practices. Even as mechanical engineer I can understand that all Integrated Circuits will “naturally disintegrate themselves” as time pass-by and it will stop working for ever after a certain amount of years. So its an ephemera item, not a long lasting device.

What will be the expected half life of the 70´s 80´s vintage calculators in the best storage conditions?.

I made a search on the forum about the subject, andI founnd some topics – not many- and recommendations are simple (desiccated environment, constant fresh temperature,...).

As IC atoms self diffusion depends on temperature, what about the calculators storage at temperatures below 0 º C.(in dry atmosphere special refrigerator)?. Will it destroy other parts (capacitors, screens, weldings,…)?. Could it create cracks and breakdowns because of the different dilatation coefficient of different materials welding and assembling? Any experience or advise of your expert knowledge will be welcome.


R.A.