ASM-1 problems/solder flux/gotta get it off

[george & lorraine]

----------
> From: Brett Duggan <bduggan at netcom.com>
> To: synth-diy at mailhost.bpa.nl
> Subject: Re: ASM-1 problems/solder flux
> Date: 29 May 1998 18:38
> 
> 
> You guys must be using water soluble flux solder.  The flux left by rosin

> core solder should not have to be cleaned, even though I suppose it is a 
> good idea.

(george) OH IT MOST CERTAINLY IS! 
> 
> The point is emphasized when you look at the solder side of a 20-year old

> PCB that is still working perfectly and notice the layer of brown crud 
> that covers it.  I assume that this is rosin core flux...could someone 
> please correct me if I'm wrong?
> 
> Brett D
> 
(george) You are dead right that's what it is but because of higher board
population,sensitivities of modern ic's etc: etc: your ,say,Minimoog could
get away with a much lower pec cleaning regime than your present day Korg
plastic musical compromise 

> > > Oh yes - clean the circuit board to remove *any* solder flux. When
you
> > > think it's clean, clean it again!
> > > 
(george) That,s what the military manufactures do!.Then conformaly coat the
board(seal it with a non conductive layer of resin).Contrary to popular
belief most military aircraft go in through pilot error! not avionic's.  

> > > [Luke:] I've heard people stress this point before. What exactly is
the
> > > reason for this ?
> > 
> > Coz otherwise it won't work, doh!   :-)
> > 
> > No, seriously, seems like solder flux is somewhat conductive, which
> > means that you'll get small leaking currnets through the flux between
> > points that should not be connected. That is Not Good. Granted, it's
> > not very big currents at all, but then again our ears are very
> > sensitive to very small differences in, say, pitch, so...
> > /Moxie (At least that's what I think)
>