[sdiy] Pro-One membrane keyboard

[mark verbos]

is this the same thing that makes the buttons on an Alesis MMT-8 get 
"difficult" ?

i would like to solve that one, once and for all.

mark

Grant Richter wrote:

>The Korg Poly 6 and others have this "resistive elastometer" design.
>
>It is no big deal.
>
>The problem is oxygen forms a non-conductive layer of oxides on top of the
>carbon impregnated plastic. It can be removed by mechanical means
>(scrapping, sanding). The lay is only 0.001" thick so not much scrapping or
>sanding is needed. Oxidized plastic is shiny, where as conductive plastic
>has a matte finish.
>
>I use 1 or 2 strokes of 600 grain wet or dry paper to break the oxide
>barrier and restore a matte finish which is conductive. Clean with isopropyl
>alcohol after sanding.
>
>Clean the PC contact with alcohol also but do not abrade, they will
>variously have gold, tin or carbon coating. But in my experience, the
>problem is with the contact on the pad not the PC board.
>
>>From: greg montalbano <greg.montalbano at ucop.edu>
>>Date: Mon, 06 May 2002 08:04:50 -0700
>>To: synth-diy at dropmix.xs4all.nl
>>Subject: [sdiy] Pro-One membrane keyboard
>>
>>Over the years, I've performed service &/or modifications on several SCI
>>Pro-Ones, but the one I'm working on currently is the first I've ever seen
>>with the
>>infamous membrane keyboard.  There are problems with intermittent key
>>response, but this thing looks so cheesy from the outside, I'm hesitant to
>>take it apart.  Can anybody who's had experience with these give me some
>>advice?  Is it worth the trouble to get inside?  Is there any way to repair
>>those sheet-plastic circuit traces?
>>
>>--wouldn't normally be so timid, but it's not my machine;  I'm always more
>>cautious with other people's equipment than I am with  my own (if I blow up
>>my own, that just gives me an excuse to buy NEW stuff).
>>
>>~G
>>
>>"The music business is a cruel and shallow money trench, a long plastic
>>hallway where thieves and pimps run free, and good men die like dogs.
>>There's also a negative side." - Dr. Hunter S. Thompson
>>
>>
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