Non clicky HP41 key

[isanchez]

Hi,
just to contribute with my experience.

During the past month I have been working in a couple of 41c, with very low serial numbers (1950xx). They implement the oldest display driver, tall keys, and if you look carefully at the finish of the keyboard mask, it is looks different to the typical 41c. It looks "painted" in a metal plate more than "printed" and the finish is very smooth.

Advice: Be very carefull when using the Deoxit, that does not touch this "painted" type of keyboard mask...or it will dissolve the letters and the black paint, and ruin the calculator ..., please take this into account. I recieved one with this problem from one friend and I had to change the keyboard mask. It is a pity because this model is very rare.

One of the old 41C was VERY dirty...I have seen and worked with dozens of HP41s, but none like this...It is very usual to find coffee or beverages residues that get "gummy"...
My recommendation: put ONLY the keyboard in vertical position (REMOVE THE BOARD APART) inside a glass of water with non aggressive detergent (like the one you use to clean dishes or wash your hands). Keep the display out of the contact with the water. Leave it for one day or more and change the water (now without soap), from time to time repeatedly press the keys, specially the most affected ...after this use a hairdryer to dry it (avoid very hot air). Be patient and dry it carefully. I have done it and all the dirtiness was removed successfully. After this you can apply the Deoxit if the remaining problem is the oxid...

[I insist: always keep the display out from the contact with the water. Only the keyboard can be in contact with the water].

Apart from this, I have noticed that the click of the row formed by "1", "2" and "3" had not the same "feeling" in both old 41c's calculators. The "click" was not as noisy as in rest of the keyboard...Now you mention that the 1,2 & 3 in your calculator behaves similar...
This makes me think that, maybe, there is something different in the design of this row in the keyboards of these 41s, or it is affected in some sense by the presence of the two lower posts...think that could be enough to improve the keys touch/reliabilty, but they will not behave exactly as the rest.

This is all,
kind regards

Ignacio