[sdiy] D-70 red goo of death

[cheater cheater]

Wow it really looks like they've solved it! Who would've thought. The
answer is a water solution of caustic soda.

Just make sure to have eye, respiratory, and skin protection while
using it, because it's really nasty stuff.

Cheers,
D.

On Sun, Jan 27, 2013 at 3:44 PM, Mike Gorman <mikegorman at btinternet.com> wrote:
> 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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