Re: After Lisa Keyboard from Simmie on 2006-03-08 (lisalist1)

From: Simmie <michael.simshauser_at_email.domain.hidden>
Date: Wed, 08 Mar 2006 08:03:54 -0800

Jason,
I don't have a current Lisa keyboard unfortunately, but will assist in maintaining once I get one =)
Thanks.

Jason Perkins wrote:
> What's wrong with your current one? Have the foam contacts degraded? You can
> make new ones... Helmut had some excellent suggestions.
>
> "
> on 06.11.2005 13:56 Uhr, Philip Lord at philip_at_email.domain.hidden wrote:
>
> > I have a spare keyboard I'd like to get going. There are maybe 10
> > dead keys, and a few really sticky ones. what causes them to stick?
> >
> > P
> >
> >
> > On Nov 6, 2005, at 7:36 PM, macmoni wrote:
> >
>
> Hi Phil,
>
> the Lisa keyboard is totally different from other Mac keyboards- the Mac
> uses switches (Alps inc.) which can produce corrosion over the years, but
> not the Lisa keyboard:
> The Lisa uses a 3mm-4 mm thick foam material ( as found in many candy
> packages/boxes or tool boxes etc...)
> This foam material is glued to a small round plastic disc on one side to
> "snap" inside the key itself. On the other side there is a special metallic
> looking foil (like christmas paper)- this foil is not electrical conductive!
> Don't use any aluminium foil- this could ruin your Lisa keyboard.
> Recycle your foil pieces and reuse them again.
> As a replacement for the glue don't use fluid glue- this may ruin your
> keyboard- just use a sticky glue ( Pattex etc...)
> The foam material deteriorates over the years and forms a kind of sticky
> mess... this produces the sticky effects on several of your keys.
> The keyboard uses a "capacitive" concept- a switch is built from an
> aluminium pad on the PCB and the non-conductive metallic looking foil.
> If you press the key, the foil presses against the pad (under the pressure
> of the foam material) and forms a capacitor- this capacity change is
> translated into an electrical impuls. if you use fluids or pressured air,
> you can easily ruin your keyboard. You have to open it very carefully and
> reconstruct all key switches with new foam material. Don't forget to clean
> the pads on the PCB from sticky glue and foam smudge.
> The whole work took me a full afternoon- but if you completed your task you
> have a brand new fully operational keyboard.
>
> Measurements with an Ohm meter is not possible- you can only measure a
> capacity change with a capacity measurement tool- but that is not
> necessary.
>
> I have successfully refurbished 3 keyboards- they are fully operational now,
> and will be for the next decade...
> there was no need to solder anything... only cutting foam disks- you can use
> Guido Deiana- he has successfully completed the same task as I did.
>
> Helmut
>
>
> P.S.: Don't use any cleaning fluid!
> This ruins all!
> "
>
> -Jason
>
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> Content-Transfer-Encoding: quoted-printable
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>
> What's wrong with your current one? Have the foam contacts degraded? You can make new ones... Helmut had some excellent suggestions. " on 06.11.2005 13:56 Uhr, Philip Lord at <a href="mailto:philip_at_email.domain.hidden">
> philip_at_email.domain.hidden</a> wrote: >
> I have a spare keyboard I'd like to get going. There are maybe 10 > dead
> keys, and a few really sticky ones. what causes them to stick? > >
> P > > > On Nov 6, 2005, at 7:36 PM, macmoni wrote: >
> Hi Phil, the Lisa keyboard is totally different from other Mac
> keyboards- the Mac uses switches (Alps inc.) which can produce corrosion over
> the years, but not the Lisa keyboard: The Lisa uses a 3mm-4 mm thick foam
> material ( as found in many candy packages/boxes or tool boxes
> etc...) This foam material is glued to a small round plastic disc on one side
> to "snap" inside the key itself. On the other side there is a special
> metallic looking foil (like christmas paper)- this foil is not electrical
> conductive! Don't use any aluminium foil- this could ruin your Lisa
> keyboard. Recycle your foil pieces and reuse them again. As a replacement
> for the glue don't use fluid glue- this may ruin your keyboard- just use a
> sticky glue ( Pattex etc...) The foam material deteriorates over the years
> and forms a kind of sticky mess... this produces the sticky effects on
> several of your keys. The keyboard uses a "capacitive" concept- a switch is
> built from an aluminium pad on the PCB and the non-conductive metallic
> looking foil. If you press the key, the foil presses against the pad (under
> the pressure of the foam material) and forms a capacitor- this capacity
> change is translated into an electrical impuls. if you use fluids or
> pressured air, you can easily ruin your keyboard. You have to open it very
> carefully and reconstruct all key switches with new foam material. Don't
> forget to clean the pads on the PCB from sticky glue and foam smudge. The
> whole work took me a full afternoon- but if you completed your task you have
> a brand new fully operational keyboard. Measurements with an Ohm meter is
> not possible- you can only measure a capacity change  with a capacity
> measurement tool- but that is not necessary. I have successfully
> refurbished 3 keyboards- they are fully operational now, and will be for the
> next decade... there was no need to solder anything... only cutting foam
> disks- you can use Guido Deiana- he has successfully completed the same task
> as I did. Helmut P.S.: Don't use any cleaning fluid! This
> ruins all! " -Jason 
>
> ------=_Part_266_6115550.1141833283773--

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