Victor

We've put quite a bit of effort into this, but the fact remains.
After removing the suspect components (which fail during test of the
assembled product) we find that some pads on the component are gray/brown.

Further analysis of these darkened pads, show that they probably never
gained a proper intermetallic connection. This kind of fault is a real
problem, as it's one of the faults we cannot detect by any other means than
functional testing. And even then it's not guaranteed the product will
continue working.

We put focus on this problem, due to our customers finding products failing
after thermal stress testing. (The boards were fully functional as they
left our site)

Upon removal, we found several black pads beneath the failing components.

Rgds
Tore

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