HP48 Series Keyboard Design

[TomC]

As the issue of HP48 series keyboard failures continue to arise - and I'm sure it will continue with time - I've been thinking about a more robust replacement.

As I recall, the keyboard interface is designed such that there is a significant level of resistance from each one of the keypad locations.

Is the amount of resistance for each of these keypad locations documented anywhere?

Thank you,
TomC