[sdiy] Re: Broken SH-101 - ideas wanted...

[Dave Magnuson]

----- Original Message ----- 
From: "Florian Anwander" <fanwander at mnet-online.de>
To: "Analogue Heaven AH" <analogue at hyperreal.org>; "Synth-DIY" 
<synth-diy at dropmix.xs4all.nl>
Sent: Monday, August 17, 2009 6:04 PM
Subject: [sdiy] Re: Broken SH-101 - ideas wanted...

<snip>

> So I picked a "trouble free" area on the pcb and tried to clean it with 
> alcohol. Bang... the surface became white, muddy and sticky. It feeled 
> like the remains of old gaffer tape. I tested with a similare area of the 
> sliders pcb, and there was nothing like that.
> Now I did a first try with alcohol and a tooth brush and the first (very 
> intermediary) result looked like that:
> http://fa.utfs.org/diy/rolandsh101/surprising-SH-101-board.jpg
>
> It is really unbelievable. This is not the first pcb that I have the my 
> hands and I have seen a lot of pcb which had been soaked with beer, coke, 
> cat pee and other stuf, you and I wo not want to know. But I never have 
> seen a pcb covered with something like that, which was definitely not 
> visible while several hours of work.
> I only wondered a little bit, why the mainboard pcb was slightly darker 
> than the other pcbs.

<snip>

Hi Florian,

My own SH-101 is covered and I mean COVERED with some sort of residue... 
almost 0.5mm thick in spots.    You can see actual drips and runs in the 
coating.  I can't recall if it was only the voice PCB or if it also existed 
on the slider board.

It doesn't seem to clean off very nicely with flux remover, so I was 
thinking it may be a conformal coating.   That voice PCB is fairly close to 
the metal bottom panel.   Perhaps the coating was intended to protect 
against shorts if a stray bit of wire or metal ended up in the case??

just a thought...
Dave Magnuson