John,Kim

Does replacing the capacitor result in good/pass unit? or does it fail
after extended power on times?


Can you measure a short on the capacitors before functional testing?

After functional testing, is the part completely shorted or just leaky?
Remove component and test?

Could it be EOS ( electrical overstress), is the voltage rating on part
greater than working voltage in UUT (unit under test).

Tom B.



----------
> From: John Mastorides <[log in to unmask]>
> To: [log in to unmask]
> Subject: [TN] Soldering SMT Tantalum (CWR09) Caps
> Date: Wednesday, January 06, 1999 9:02 AM
>
> We have been experiencing some shorting of surface mounted tantalum
> capacitors (CWR09) which is showing up at functional test following a
> completely automated SMT process.
>
> A profile of the reflow process indicates that temperatures are within
> manufactures recommendations for these parts.  However, there are
subsequent
> operations which could be applying excessive heat to these parts. We are
> considering hand soldering these devices just prior to final test in an
> attempt to reduce frequency of failures.
>
> We have already established that the supplied capacitors not faulty.
>
> Some concern has been voiced that hand soldering is not the recommended
> method of mounting these parts.  Is anyone out there aware of concerns
> related to the reliability of hand soldering SMT tantalum capacitors?
>
> Any other recommendations?
>
> Kim O'Haver
> 813 972-6574
>
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