die Schwalvenbergs
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After a repair of broken screw posts my HP-41CX (coconut) runs very satisfying, almost without any problem. (I can’t say if the below mentioned problem existed before, I haven’t used the CX for years).
BUT - the time in the CX runs much faster than it should. One minute standard earth time means 2:56 minutes in the CX universe. With this big delta to the real time the Correct function does not help. Did anyone come across this problem? Does anybody have a hint what can be the reason?
All commands of the Timer Module U11 work correct, no problem at all (Date, CLKT, DDAYS, etc.), thus I hope that the problem is outside of the U11 (HP Part Number 01LF6-0001).
The Timer U11 uses a crystal / quartz Y1 with a parallel switched resistor R4 (22 MΩ).
Has anybody seen a specification of the Quartz/Crystal (HP Part Number 0410-1381)?
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01.04.2014
The world most famous and in my opinion best handheld computer in the world was and is the HP-41C/CV/CX of Hewlett-Packard. Build and sold in the 80s it has reached "cult status" and a worldwide community of HP-41 enthusiast are keeping the information about it alive.
I can call a HP-41CX my own, which accompanied me during my studies. It was exactly that what a student needed in the 80s, studying electrical engineering. Together with a Math-Module and a card reader at least the electronical support in the exams was perfect.
After several years passed by without touching the device I found out last week that my beloved HP-41CX was "dead" even though powered up with new batteries. Even worse, after I took out the card eader, I noticed that I could spread the upper and lower cover at the upper part of the hp easily.
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Here one can see the blasted componenton the mainboard of the HP-41CX.
Unfortunately this component is not specified, nothing is written on it.
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First step is to remove the screws which keep the hp41 together, usually. The screws are located under the rubber feet, and under a grey foil, at least in my model.
After I opened the calculator it became immediately clear that the screw posts, which task it is to support the screws to put proper pressure onto the contacts of the key- and mainboard. Without proper posts the contact between different parts of the hp won't work correctly. A known problem.
As you can see on the picture the area around the upper screw holes at the lower cover were broken. In addition at the upper part the inner 2 of the "guidance" pins between the upper posts were broken not able to keep the in the right position.
Furthermore the right post of the lower ones was broken. Altogether a quite substantial damage even though my hp war treated gently in drawer.
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