apple Lisa2. Keypads
ray at arachelian.com
Thu Dec 23 19:27:44 CST 2010
On 12/23/2010 03:06 PM, Terry Stewart wrote:
>> Wow, I've not seen too many Lisa keyboards, but none whose mylar was
>> that damaged. Well, let us know how the repair went.
> Yes. I haven't opened the other two but I'm sure I'd be looking at
> the same thing.
> Ray, any thoughts of what might cause this deterioration? Would it be
> because it's been kept in a humid enviromnent and/or a hot
> environment? Or excessive use? Any ideas?
Wise ass answer to why anything deteriorates would be entropy. :-) No
idea. I would guess, and this is just a guess, that since these
materials are a depositing of metal particles on top of plastic, that
the bonds wear out over time. Whether that's because of oxidation, or
mechanic wear and tear. In this case since almost all of the keys are
worn out like that, I would say it's unlikely to be mechanical wear and
tear. This is because most people don't use every key on the keyboard
with the same frequency. You'd find some keys like the "CLEAR" key on
the numpad would be almost never used.
So if most of them are totally worn out in that way, it's got to be some
chemical process. So that's the beauty of using taped over aluminum
foil. It last a hell of a lot longer than mylar. It's unlikely that 10
years from now it would disintegrate like the mylar did. The hardest
part is cutting the rounds to be all the same shape/size. Not too hard
if you find a plastic tube of the same diameter as the original mylar
rounds and use an Xacto-knife (aka- small sharp razor on a pen.)
> I'm tossing up whether or not to buy some replacements or make them.
> I know REAL classic computer guys don't BUY replacement Lisa
> keypads...they MAKE them. However I can afford it, and am inclined to
> go that route. (-: . The ones I'm looking at getting appear in good
> condition BUT I don't want to get them only to be faced with the same
> problem a few years down the track.
Make it yourself, less trouble. And while you're at it, find some
foam. I'd replace all foam and mylar in all of the keys in the
keyboard. This way you won't have to redo it again for a long time.
I'm not exactly sure where you'd be able to get new keypads from
anyway. Maybe there's a place that makes these still, I don't know.
But once you make one or two replacement keys and verify that they work,
repeating the process is very easy. And better yet, if you replace all
of the foam now, you won't have some keys that feel mushy and others
that feel stiff. Instead, they'll all have the same tactile feel. The
keyboard will feel like a new keyboard. Well worth the 1-2 hours of
But, just out of curiosity, where exactly would you order keypads from?
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