"N Cook" wrote in message
...
A 200W combo, UK made 2002, with one solder joint to a small on-end
electrolytic failed
so could be just due to vibration/resonance.
But it is on a board with obvious conical solder joints so perhaps the
most
likely inherently weak joint to fail first. The larger (heatsinky) joints
are shiny and conical, redone by hand with junk solder maybe, but all the
other small joints look horribly grey. On the other board all conical
joints
but all bright silvery colour. What is the consensus of the panel - redo
all
the grey joints with Pb-Sn solder and leave the bright ones, or if it aint
broke - don't poke. ?


I really can't make my mind up on this. All the regulars on here know my
views on lead-free solder, and I must admit that I am inclined to go over
lead-free joints that look *particularly* suspicious, with //proper//
solder, but as I've said here before, there are two schools of thought on
this among the metallurgical experts as to whether mixing lead-free and
leaded solder in the same joint, produces one with long-term compositional
stability.

Add to this that now the full legislation for RoHS is in place, as UK
repairers, we are fully obligated, officially under threat of EU law, to
repair equipment originally constructed with lead-free solder, and placed on
the market after July 2006, using *only* lead-free. This means that by
reworking a lead-free joint on such an item with leaded solder, we are
officially inviting the wrath of the solder police, and I guess, prosecution
for what they are now calling an " eco crime ".

I haven't heard of any such prosecutions yet, but in these days that we have
now where people are getting prosecuted and heavily fined for (
accidentally ) putting the wrong type of recycle waste in their household
bins, I'm sure that the day can't be far away when some poor engineer gets
tricked into breaching the legislation, by some over-zealous trading
standards person ...

Arfa