[sdiy] "re-cap" when it's SMT?

The Laboratory of Sound info at labofsound.com
Thu Nov 7 10:00:04 CET 2013

Glad to hear it was C175.

Regarding your question about how to clean corroded traces etc., I get 
good results with copper polish rubbed in with a toothbrush or 
interdental brush. After that of course a thorough rinsing with water.

All the best,


On 2013-11-07 06:31, Pete Hartman wrote:
> and patience to let it dry :-D
> Good news!  I replaced C175 only, touched the corroded ceramic cap
> with my iron to reflow the solder, and the hiss is gone.  I measured
> the cap after taking it out, and the nominally 10uF cap was reading
> about 4uF....
> There's some other work necessary to recondition it (the Alpha wheel
> is stuttery, there's a broken key), but the biggest negative is gone
> and I'm pretty darn happy about it :-)
> I didn't clean it all up, I wanted to verify whether the single cap
> would solve the problem.  Now that I know it does, I can do some
> judicious cleaning while I'm doing the rest of the fix up.
> Thanks!
> Pete
> On Wed, Nov 6, 2013 at 11:22 PM, cheater00 . <cheater00 at gmail.com> 
> wrote:
>> On Thu, Nov 7, 2013 at 5:13 AM, Pete Hartman <pete.hartman at gmail.com> 
>> wrote:
>>> Bringing the original topic of the XP-50 repair back up because I 
>>> have
>>> some appropriately sized SMT electrolytic caps now....
>>> Now that I have the PCB removed (I was able to figure out all the
>>> connectors without damaging any, thankfully), I can see that there 
>>> are
>>> a couple of vias that show signs of corrosion as well as what was
>>> apparent on the ceramic caps (which I neglected to get replacements
>>> for, but there you go).
>>> Is there a preferred method of cleaning this kind of corrosion out 
>>> of
>>> those vias?  Or off the ceramic caps, for that matter?  I can 
>>> replace
>>> them as well if need be but if there's a sufficient solution without
>>> waiting another few weeks to get another order together, it'd be a
>>> good thing.
>> A shower head and a toothbrush.
>> D.
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