Calculator blog

Musings and comments about our common interest


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New zebra development!


We have received the samples of a new design for zebras for the HP41 family of calculators. This design will solve the current issues that the elastomeric zebras have. (This part is referred to in the service manual as 1251-5731 )

Let's see it:


Initial tests seem very good - 100% connection on first try! Dimensions are perfect - what we need to find is the optimal fill for the zebra part: how thick and compliant does it need to be, and which material is the best for the application, since it has to be durable and cannot rot, corrode or dissolve. Initial tests show that it works even without filling - the compliance of the film is enough to ensure good connection. However, we will put something in, to ensure durability.

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A new Zebra batch has arrived


zebralinWe have just received a new batch of zebra connectors for HP41c. The compound chosen is more flexible than the previous one. The thickness has been optimized to avoid gaps in the lower part of the calculator, while keeping good pressure between both circuits when pressed together.

To do so, we have a central conductive part surrounded by two softer isolating silicone sides.

You can see it in the pictures beside. 

In some cases (depending on you application and what the old zebras were) you may need or not the optional zebra holder.

The price for a pair has been lowered to 6€. 


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