HP67 : repairing a keyboard

[albertofenini]

As you can see is a very old keyboard, on the contrary the HP45 we used was well kept.
The other HP67 keys were less strong than normal keyboards while the HP45 a little stronger.
I think it was a good compromise, and on the other side the only available option.
The line we replaced was physically broken, so it was a no go situation, the rest of the
unit was worth the work done and the feeling is very very close to all of our units.
Given that the upper part of the keyboard had almost no corrosion, I also think that someone
had spilled something and not taken too much care in cleaning.
This calculators have a thin plastic film between the keys and the keyboard, which can prevent
liquids to pass thru, but only in small amount.