[sdiy] cr-8000 button fix progress

[Dave Magnuson]

Hi Gregory,

I typically clean Roland rubber membrane contacts with a pencil eraser (be 
gentle!) to remove the oxidization on the surface.   I then treat the rubber 
with pinch roller cleaner for reel-to-reel (and cassette) decks.    It's a 
cleaner and conditioner that is supposed to help keep the rubber from drying 
out.  My bottle is Teac brand.... so check Teac/Tascam to see if they still 
make it.

Has worked well for me so far.   Be sure to use pinch roller cleaner... not 
tape head cleaner (which is almost straight alcohol).   The alcohol will dry 
out the rubber.     I also clean the metal portion of the contacts with an 
eraser and rubbing alcohol.   I've repaired about 10 keyboards this way with 
no problems yet.

Another side note....  this works great on tarnished contacts in Technics 
SL1200 tonearms... eraser and alcohol.   Works much better than the typical 
DJ fix (licking the cartridges before putting them in)... Makes me cringe 
every time I see someone do it.   (Not to mention what one may find on a 
club's house tables...yuck!... nothing I'd want in my mouth)

Dave Magnuson


----- Original Message ----- 
From: "gregory zifcak" <zifcak at hotmail.com>
To: <rude66 at gmail.com>; <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, May 11, 2006 4:14 PM
Subject: Re: [sdiy] cr-8000 button fix progress


> i'm considering this. my one hesitation is that maybe the pads have dried 
> out after 20 years, and that's why they deteriorated. if that's the case, 
> they might fail much quicker next time. i'm not sure if they're supposed 
> to be hard or somewhat spongey. hmm.
>
>
>>From: rude66 <rude66 at gmail.com>
>>To: "gregory zifcak" <zifcak at hotmail.com>
>>CC: synth-diy at dropmix.xs4all.nl
>>Subject: Re: [sdiy] cr-8000 button fix progress
>>Date: Thu, 11 May 2006 22:07:55 +0200
>>
>>it depends how long the switches pad would work. if it's taken 20+ years 
>>to
>>get to this state, then hey.. i'll worry about it in 20 years again..;-) 
>>but
>>if it'll only last 3 years or so, something more permanent may be in 
>>order..
>>
>>r./
>>
>>
>>
>>
>>On 5/11/06, gregory zifcak <zifcak at hotmail.com> wrote:
>>>
>>>well,
>>>
>>>i've managed to desolder all the buttons. whew! that IS labor intensive. 
>>>i
>>>definitely want to come up with a permanent solution so i don't have to 
>>>do
>>>this again.
>>>
>>>looking at the switch mechanism, there are two metal plates, each with a
>>>tiny bump. these come into contact with the conductive material on the
>>>other
>>>part of the switch, bridging the connection. the worn out buttons have 2
>>>little worn holes in the conductive pad, apparently caused by the 
>>>repeated
>>>poking of the tiny bumps.
>>>
>>>now, it looks like i could just rotate the conductive pads 90 degrees and
>>>have a fresh surface to press against the bumps, but they would 
>>>inevitably
>>>fail again the exact same way. i'm wondering if these bumps would also
>>>wear
>>>away at conductive paint or aluminum foil glued to the pads.
>>>
>>>any thoughts?
>>>
>>>greg
>>>
>>>
>>>
>