7 Oct
2003
7 Oct
'03
11:33 a.m.
I have been working on a DEC Pro 380 and the LK201 keyboard I have
causes the Pro to report a stuck key and hang. So I opened up the
keyboard thinking I could clean out whatever had jammed in there.
Looking at it, I don't quite know how this thing works. Each key is
supported by a "cantilever" spring. This spring has a piece that looks
like it has a contact of some sort, but this is all on top of a layer of
rubber and it doesn't even look like the "contact" touches the rubber.
Below the rubber is a piece of clear, flexible plastic with circuits on it.
So does anybody know how this thing works? Contacts? Capacitive?
Inductive? Has anybody ever fixed one?
-chuck
8 Oct
8 Oct
8:33 a.m.
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9 Oct
9 Oct
4:52 a.m.
Tony Duell wrote:
We had a totally wrecked one at a place I was working,
so we (the system
manager and I) took it apart one night. Cut off the heat stakes and
pulled the layers apart. Putting it back together proved impossible,
there simply wasn't enough plastic left to re-stake it. I would not
recomend taking one apart that you plan to re-use.
You can sometimes build up the plastic using a "spin welding" technique.
Take a chunk of plastic (a part tree from a plastic model usually works
well),
and put it into a drill chuck. With the drill running moderately fast
(goggles
are definitely recommended), press it against the spot you want to weld it.
Friction will melt the two together.
Success depends on how well the two plastics will bond together.
Some plastics will not bond well together.
10 Oct
10 Oct
7:25 a.m.
Tony Duell wrote:
I got it to work, but I was very lucky. The key that was stuck was F10;
top row on the open end of the plastic layers. I slid a piece of
cardstock in between the contacts and no more stuck key.
So the DEC Pro gets through the diagnostics, boots, and enters the VAX
console program... Now if it was only connected to an actual VAX.
I have been
working on a DEC Pro 380 and the LK201 keyboard I have
causes the Pro to report a stuck key and hang. So I opened up the
keyboard thinking I could clean out whatever had jammed in there.
The clear plastic part is in 3 layers. The top layer has conductive
traces on the bottom surface. Then there's an insulating sheet with a
hole under each key (and no traces). And the bottom layer has traces on
the top surface. There are circular pads on the ends of the traces under
each key, over the holes in the insulator.
-tony
-chuck
7745
days inactive
7748
days old
3 comments
3 participants
participants (3)
-
ard＠p850ug1.demon.co.uk -
chd_1＠nktelco.net -
kth＠srv.net