HP-71B - Two keys responding erratically

[anetzer]

Hello,

I have found an early 71B which has two keys on the lower left edge (ON and Shift-f) which respond peculiar: Pressing them rather determined often gets no response but pressing them rather lightly and shortly and gingerly works.

I do not really want to disassemble a keyboard assembly that is rather well preserved elsewhere. Does anybody know less invasive tricks? Is there a possibility to clean the keyboard, apply contact spray etc without cutting and remelting keyboard stakes and disassembling the keyboard proper?

Thank you!

Andreas