Martin Crossley wrote:

Arfa Daily wrote:
"David Farber" wrote in message
...
I occasionally see this residue where the components are soldered.
Is this flux? Something else?

http://www.pbase.com/image/83992679

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA



I'm not sure what that is, but it doesn't look like any flux residue
that I've ever seen. The little brownish 'blobs' on the tops of
Q200's legs do, as does the lttle patch at the upper edge of its
centre leg. If it is flux residue, I'm sure that you would agree, as
a repairer yourself, that it is very unusual for it to be white like
that, which is why you are asking for the opinions of others on
here, I would guess ? Perhaps solder guru Smitty could offer an
opinion from the production point of view.
Arfa

I've seen it before; It's flux residue that has become damp, then
dried out again. Is there also a touch of rust on the end of the
transistor's legs (the brownish blobs)? And possibly a bit of
corrosion on the edges of the tracks, or just poor resist? Yet I
can't see any corrosion on the 0R22-resistor, but the solder is a bit
grainy, so it's probably either lead-free or has been damp. I bet
the white deposits will turn back to ordinary flux deposit if heated.
Martin.

looks like flux residue. But the boaed has not been washed and dried
properly after soldering process.
rw

--