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

[Ben Lincoln]

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: