Yuriy Khapochkin wrote:

Jon,

There could be problems with hand soldered components.

Ceramic capacitors, for example has a tendency to break and
become resistor with 10-100 Ohm resistance.

Probable, due to thermal tension from manual soldering.

I had such problems in the past.

Worst of all, it usually happens weeks or even month later.

That's why I don't want hand-soldered SMT board go to the field.


Interesting, but I have never seen this. I have deployed several hundred hand-soldered
boards to customers all over the world. I HAVE seen broken caps on rare occasions,
and fixed them. But, I've never seen this sort of trouble, except in manual rework.
I definitely do not reuse removed SMT components except on VERY prototype
pieces.


My feeling is that manual soldering subjects parts to MUCH less thermal stress
than IR reflow systems. Since these ceramic parts have VASTLY lower TCE
than the PC board, the idea that fully heating the entire PCB and components
and letting them cool together doesn't seem to be of any benefit to me.


Jon



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