HP 15C Keyboard

[Charles]

I have an HP 15C which passes all the tests but the 9 key sometimes doesn't register or puts 2 nines in the display. I'm reluctant to open it up but would consider it. Does anyone have any suggestions ?

Thanks

[Randy]

If the key clicks okay and has the normal travel, it should be fine.

This is an adaptation from many posts from MoHPC regular David Smith:

"Your most likely problem is a dirty switch contact for the 9 key. These can be cleaned fairly easily if you open up the machine (one screw under each rubber foot).

Beneath each key dome is a tiny hole in the circuit board. Make a tiny wire brush out of three wire brush bristles twised together, mounted in a pin vise, and trimmed square. Place a drop of 91% isopropyl alcohol on the hole, dip the wire brush in more alcohol, and gently "scritch" around in the hole with the brush. In stubborn cases you may have to repeat a few times."

For more on how to open: http://www.hpmuseum.org/disasm.htm

Good luck, post again if you need more help.