> The bugaboo is this: IF these are ESD failures at assembly time,
> why are these making it through production and out to the field
> before failing?  Corollary: why are only these components failing?

When I was a student we were told this is exactly the nature of ESD damage. The 
device is "weakened" by ESD and will function initially but fail after some time under 
the stress of normal use (by Murphy's law not untill the customer is using it).

Why only that component failing in your case? It may be the only component 
subject to ESD damage during assembly, more susceptable to ESD than other 
parts, there may be other parts damaged by ESD but this one fails sooner, or a 
dodgy batch of parts more susceptable than normal.

Anyone else noticed local electronics stores becoming more ESD ignorant? Couple 
of examples: Jaycar here has no anti-static straps or packaging for chips. Dick 
Smith offered to install extra laptop RAM at the counter, no ESD protection, I said 
no thanks. The typical mindset is "Well I've never damaged anything with static so it 
must be a myth." As described above, failure can occur a long time after the 
damage is done and so does not get attributed to the actual cause.

-- 
Brent Brown, Electronic Design Solutions
16 English Street, St Andrews,
Hamilton 3200, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell: +64 27 433 4069
eMail:  brent.brown@clear.net.nz


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