[sdiy] D-70 red goo of death

[cheater cheater]

Your only bet is to talk to a chemical engineer.. I wonder if David
knows anyone in his dept who might know what to do..

Cheers,
D.

On Sun, Jan 27, 2013 at 7:04 AM, Dave Brown <davebr at earthlink.net> wrote:
> I have a D-70 with the red goo of death.  Keys are stuck together, the
> weights are falling off the keys, and it’s dripped all over the PCB and
> rubber keypad strips.  Some of the keys stopped working so I took it apart.
> You have to disassemble most everything to get the keyboard out.
>
> I can’t find anything that dissolves this goo.  Lacquer thinner softens it a
> bit, but also everything else.  Acetone doesn’t touch it at all.
>
> The keyboard PCB is made up of two flex circuit boards with encapsulated
> diodes and carbon key button pads.  I think the goo has probably destroyed
> some of the runs.  To make matters worse, this flex circuit board is
> press-fit to another flex circuit board which wraps around to a connector to
> a flex cable to the control PCB.  Where the two flex circuit board pads were
> pressed together the one stuck to the other so now all the edge pads are
> missing (well, really they are stuck on the other flex circuit board).  I
> have to believe there are probably microcracks as well.  The only way to
> really test this is put it all back together and see if the keyboard works.
> I’ve done that once and ended up with 4 that didn’t function.
>
> At this point, even if I could repair the traces, I assume the red goo will
> continue to soften and drip.  Right now I’ve put it all back together
> without the keyboard and am using it as a MIDI synth module.  It isn’t that
> great of a synth with only 64 presets but I hate to send it to a landfill.
>
> Has anyone found a way to clean up this red goo?  My web search results all
> say no one has yet.
>
> Any thoughts on repairing the traces on the flex circuit board?  I would
> need some conductive paint that I could paint over the runs.  It does look
> like except for the keypads it has a mask on it so I would have to try and
> remove that without removing the traces in order to repair them.  Who has
> had good results with conductive paint and what did you use?
>
> I just hate junking old electronics.  I’ve even thought about repackaging it
> into a rack unit but the synth just isn’t worth the effort.
>
> Who do you suppose picked this red glue that really isn’t a glue.
>
> David J. Brown
> Email davebr at earthlink.net
> Website http://modularsynthesis.com
>
>
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