mysterious corrosion

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gang of elk

Well-known member
Joined
Jun 16, 2004
Messages
257
Location
tn, usa
i recapped this daughter board amp card last december (a year ago) and looking at it now i see some corrosion on some solder points, only at the points which were resoldered at the time of recapping (using 60/40 rosin core solder).

is the rosin in the solder i used reacting w the old solder and causing this?

i was about to start scrubbing the trouble-spots w a toothbrush and vinager to stabilize it for now, rinse w distilled water and dry. any other ideas?

i haven't seen this w any other pcbs that i've soldered using the same 60/40. (EDIT: several other pcb's relating to this piece show the same problem, pcb's of different manufacture do not)

check out the chalky circles, like in the upper left hand corner.

KWback_2.jpg
 
ok, i'm sure that's what it is. took 2 min of googling to see what causes it and how to prevent. will clean them all and apply some CaiKleen or something, should help. it sucks but on the upside the corrosion material is easily removed by light scraping w an exacto.

thanks,
 
It isn't corrosion. Just leftover flux. On a board like this is does no harm, but it tells the world that you are not getting your joints hot enough. If the solder really melts, good electronic rosin will mostly vaporize. I'd reject that board on the basis that if the solder was not hot enough to vaporize 99% of the rosin, then the leads probably didn't get hot enough to be fully wetted with solder. And that leads to mystery intermittents down the road.
 
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