nanonote keyboard broke
Werner Almesberger
werner at almesberger.net
Mon Apr 18 17:28:49 EDT 2011
Jane Andreas wrote:
> OK, the photo shoot is done.
Thanks ! I'm afraid this doesn't look too good, though. From your
original description, I thought just the plastic keycap had come
off. But the picture suggests that the damage goes deeper. Here's
what I think the situation is like:
The keyboard consists of the PCB-mounted contact plus the key
assembly.
The PCB-mounted contacts are small metal domes held in place (and
isolated) with a transparent adhesive film. This is what you're
seeing in that hole.
The key assembly seems to consist of a rubber sheet, a thin metal
sheet, and the keycaps. (When you take the Ben apart, you can
easily remove the keyboard assembly and examine it.)
I think the metal sheet's purpose is mainly to prevent the rubber
sheet from being pulled from the Ben. It has openings for all the
keys.
The rubber sheet seems to be a single piece. It is shaped such
that each key has a "dome" and a knob in the middle. So the base
of the rubber sheet is below the metal sheet and the domes extend a
bit above it. The keycaps appear to be glued to the rubber sheet.
Now, in your picture, rubber still seems to be attached to the key,
complete with the knob in the middle. If I understand the assembly
correctly, this means that the metal has cut through the rubber.
If you push in the key, it may still be held in place by friction,
but it will probably fall out again.
I'm not sure if adding glue would make things better or worse. You
could remove the keyboard and try to glue the key back into the
rubber sheet, with some super glue. This would have to be done from
the bottom, or you'd risk gluing the key to the metal, which
probably won't be so good.
An alternative would be to apply some elastic glue at the edge of
the key and to glue it directly to the PCB. Again, I'm not sure if
this would make things better or worse. Also, after this change,
each time you disassemble the Ben and separate the key assmbly from
the keyboard, the repaired key would be torn off again.
If you can get a replacement key assembly, replacing the broken one
would be easy enough. The Ben is not very difficult to disassemble.
- Werner
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