Eeyore wrote in message
...


N_Cook wrote:

Eeyore wrote
N_Cook wrote:


http://www.guardian.co.uk/technology...ch.engineering

Within a whisker of failure

About time too.

Never mind the reduced reliability (see the ERA study) caused by
lead-free
solder when equipment is exposed to vibration.


Before I waste time downloading an irrelevant pdf

would this be what you be referring to :

Review of Directive 2002/95/EC (RoHS) Categories 8 and 9 - Final

http://ec.europa.eu/environment/wast...nal_report.pdf

Results of vibration testing lead-free solder from different researchers
....

Not sure if that's the one I had to be honest but looks interesting.

Graham


One small bit from that study

"Solder joint failure due to vibration becomes more significant as the
frequency of vibration approaches the resonant frequency of the component or
structure.
Studies by Chuang et al 29 and
Song et al 30 have sought to identify microstructural features that
influence the performance of conventional Sn-Pb solders and candidate
replacement lead-fre solders. The typical microstructure of conventional
Sn-Pb solders containing coarse pro-eutectic grains reduces the ability of
these materials to absorb energy during crack formation and hence reduces
the vibration resistance of joints made using these solders. "

I thoutht distributed irregularities in structures, suppressed crack
propogation.
Would seem NOT to be borne out for the case for premature failures of solder
joints for unsupported dropper resistors in mucic combos - ie amplifiers
contained within the same case as large speaker/s.
Failure in 2 or 3 years of routine use wheras more like 20 years for failure
in similar but older PbSn manufacture.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/