Keys not registering

[Funnel Bunny]

I have an HP 48G+ and some of the keys are not registering keystrokes. I took the faceplate off and saw there are two small, metal buttons underneath the faceplate that are depressed when the faceplate is attached. Initially, re-adhering the faceplate--ensuring that the metal buttons were depressed--fixed the problem, but now only half the keys register keystrokes. Has anyone encountered this problem before, or is anyone familiar with a remedy?

[Randy]

You attacked it from the wrong side. The problem is typically one of lost connection between the keyboard and logic board which can only be accessed by removing the case back and then the logic board. You'll find opening instructions on HP48.ORG.

The two metal tabs you refer to are there to make contact with the aluminum keyboard surround and connect it to the case for electrostatic discharge protection, they have no bearing on the problem you described.

[Rafael Ramos]

it can be dust or ox between the layers.
the easy solution (may be the only?) is:

1 - grab some cofee filters (paper)
2 - cut it into strips that can be inserted between the layers (you should end with a few strips of 7x120mm)
3 - fold them in two (now you have a double 7x60mm sheet)
4 - find a very thin metal sheet, 4x60x.5mm (i found good ones inside celular batery packs)
5 - put it ´inside´ the folded cofee filter strips.
6 - slowly insert it between the plastic layers of the keyboard. the paper must be dry. leave at least 10mm outside.
7 - spray some freon or whaterver you like to use on the paper.wait a few seconds
8 - slowly pull the paper and the metal sheet.

notes: do not use this paper again, neither insert the metal sheet without paper, under risk of damaging the trails or having some paper stuck inside the keyb.

hope this helps