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

[Scott Nordlund]

Is it not simply a lacquer coating applied to the PCB during manufacture?

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> Date: Mon, 17 Aug 2009 16:11:14 -0700
> From: blincoln at eventualdecline.com
> To: analogue at hyperreal.org
> Subject: Re: [sdiy] Re: Broken SH-101 - ideas wanted...
> CC: synth-diy at dropmix.xs4all.nl
>
> Oddly enough, I had the same thing happen last week while using alcohol
> to clean the PCB from a Digitech distortion pedal. I had also not seen
> it before. Maybe it's residue from a chemical used in the fab process?
>
> Florian Anwander wrote:
>> Ok, everyday you learn something new...
>>
>> After an extensive session of measuring and tracing voltages and
>> signals (btw: thanks to many kind and helpful people who sent advices)
>> I took my philatelists lense and started looking for broken or cold
>> solder joints or broken traces. With the first look at a connector I
>> was worried, because I could see in the lense something between the
>> pins of the connector, that looked like "microscopic mildew". It was
>> not visible with bare eyes (at least with my eyes, which will need a
>> reading glass sooner or later...). 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.
>>
>> I did not clean the pcb completely until now, but already the CPU
>> seemes to come back to life again.
>>
>> This story will be continued the next days...
>>
>>
>> Florian
>>
>> Florian Anwander wrote:
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