HP-97 keyboard

[Kees Bouw]

Hi,

The keyboard of a HP-97 has keys with a cross shaped stick attached which fits into a cross shaped hole. See the attached picture. What I found is that on some keys, there appears to be some sort of lubricant or grease on the small stick. On most keys I could not find any trace of it however. I could see no relation to keys being frequently used or not. I can imagine that there can be some wear from moving the stick up and down over the years, so maybe some silicon grease will be beneficial. Does anyone know if there was any lubricant or grease applied in the factory? Should I put some on the sticks anyway? Or is there a good reason not to do it?

Thanks,

Kees.

[teenix]

There is no mention of lubricant in the keyboard maintenance section of the service manual. I personally wouldn't do it because the lubricant could end up dribbling down onto the circuit board surface and contacts. Over time, the keys may get sticky as well.

cheers

Tony

[vassilisprevelakis]

also a word of advice, even though the repair manual explains in detail how to remove the keys, don't. The end of the stem where the tab that keeps the key in place is attached is very weak and can break. Back when the manual was written, you just cursed and reached for a new key in the spares bag, but now you are s****ed!!

**vp

http://www.series80.org

[Kees Bouw]

Hi,

Thank you for the replies. I have resisted the urge to use any lubricant in the keyboard because it seems unlikely that this was done in the factory.
Fortunately I have never broken a stem having disassembled two keyboards. However, I now have a HP-97 that is quite clean and seems little used, so I think I will not remove the keys. If it's not broken, don't fix it!
I am wondering how these keyboards were manufactured. The stem is cross shaped and this cross is rotated in a way that appears unique to each key. You can't put a key in the wrong position yet the same key does fit in another calculator. I think that the cylinder that it fits into was not fixed to the keyboard initially. The key may have been rotated until straight and after that the cylinder was fixed, maybe by using heat. Is such a thing possible?
Another thing that puzzles me is the people who were working in the factory, or designed the manufacturing process. Is none of those people interested in the products they worked on any more? I have never read a story about how it was done, what materials were used etc. It is a long time ago but some of them must still be around to tell the tale.

Kees.