19 Jun
1998
19 Jun
'98
9:23 a.m.
On Fri, 19 Jun 1998, Christian Fandt wrote:
I found that each of the key contacts were actually a
strip of metal about,
IIRC, 3mm or 4mm wide x 12mm long. The strip had been formed into an arch
which would stand about 1mm above the surface it was setting upon. On the
keyboard assembly's PC board, each keysite had one of these arch-like
strips spotwelded to its respective PC board pads. When assembled, each key
cap had a small boss on its bottom that when pushed down against its
respective arch-like strip would cause the center of that strip to snap
down onto a contact pad on the kbd PC board. The strip acted like the
bottom of an old-fashioned oil can when the user wanted to squirt some oil
into his machinery or whatever as it would pop down and pop back with a
definite 'snap'-action. The strip "oil-canned" as we older engineers
and
mechanics called it.
I removed the keyboard assembly the other night, but I have not been able
to separate the PCB from the mechanical layer -- even after removing the
dozen or so jewelers screws, the thing appears to be riveted together.
I was able to life the "execute" keycap enough to see that the "snap"
strip is simply gone.
We bought the replacement and I kept the old kbd.
I'm a certified Packrat!
I'm not sure if I still have it but I may run into it when I move a *heap*
of remaining stuff out of our old house and cram it into the new house in
the next weeks. I am almost sure it still worked.
Even though we both had the same key die, I'd be interested in that spare
keyboard if you ever find it and can bring yourself to part with it. I
figure I can canabalize one of the other keys, or simply replace mine with
yours since it sounds like your keyboard was basically functional when
removed.
I hate it when this happens. I've got an otherwise perfect machine that
is rendered basically useless by a small dead $0.01 switch. I'll try to
rig something up, but without being able to get that keyboard apart, I
only have a few microns of work space!
-- Doug