[sdiy] D-70 red goo of death

[Paul Burns]

This is absolutely fascinating.
regards 

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Mike Gorman
Sent: 27 January 2013 14:45
To: 'cheater cheater'; 'Dave Brown'
Cc: 'synth-diy'
Subject: Re: [sdiy] D-70 red goo of death

I recall reading about a similar issue a while ago. A bit of goggling and I
managed to re-discover the thread from the Sound on Sound Forums, here:

http://www.soundonsound.com/forum/showflat.php?Cat=&Number=623176&page=1&vie
w=collapsed&sb=5&o=&fpart=1#623176

I hope this helps.

Regards

Mike

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of cheater cheater
Sent: 27 January 2013 10:38
To: Dave Brown; David G Dixon; David G. Dixon
Cc: synth-diy
Subject: Re: [sdiy] D-70 red goo of death

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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> Synth-diy at dropmix.xs4all.nl
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