HP41's: 3D printing solution to broken back cover holes area

[isanchez]

Hello everybody,

One of most frequent problems I have encountered when repairing HP41 calculators is the fragility of the rear holes area, in the back cover. When that area is broken, the screws do not keep the pressure on the flex-connector and the calculator fails. I have tried many things without success until now.

Now I want to share with you a solution that has proved definitive. In collaboration with my friend Jose González, we have designed and tested a 3D-printed part that is coupled to the back cover, after removing the plastic that surrounds the holes. I enclose some photos...

I have been using this to repair, for the moment, two calculators with this problem. It Works great! The only thing you have to do is to clean the old broken plastic with a Dremel or similar, glue it carefully (I do not recommend cyanocrilate) and put a couple of clamps during 24 hrs...
It can also be used only in the case that there is only one hole area defective, just cutting one part.

Additionally it adds new (vertical) tabs to set the flex connector in place, so it increases the resistance in the case they still are present, or replaces its functionality, if all or any are missing.

I hope it can be of help to those who have HP41 calculators with this problem (I have in the spare parts box, more than ten back covers with this problem).

Kind regards
Ignacio

[Ángel Martin]

Ignacio, very nicely done! Thanks for sharing the news.
Will you make those parts available for purchase? I can use a couple of them, maybe more depending on cost.

Çheers,
ÁM

[isanchez]

Hi Ángel,

nice to hear from you!.

Well, the idea is to make it available, after the testing (which has been very successful) through the Calculator Store portal, at http://www.thecalculatorstore.com
José González Divasson, is the curator of the portal, based in Barcelona, and provides many support in a very interesting blog related to HP calculators. He did the CAD work, and will put it there. I do not still know the details about the price, but it will be published soon.

(By the way, I am still working in the USB rechargeable batteries design for the 41...;-D...not very confident, but...)

Kind regards

Ignacio

[Massimo Gnerucci]

Well done!

José already announced it on his May 15th newsletter.
Waiting for a price tag...

[Ángel Martin]

(05-23-2017 08:28 AM)isanchez Wrote:  (By the way, I am still working in the USB rechargeable batteries design for the 41...;-D...not very confident, but...)

That's still very high on my wish list ;-)

[isanchez]

Hi again,

The 3d part is now available through the web portal http://www.thecalculatorstore.com

Regards

Ignacio

[Divasson]

For those interested, the part is also available in Shapeways. There is also a guide for installation.

There is also a base to apply Diego's flex circuit.

[aurelio]

A nice job well done!!!
thank you for sharing...