Hi TechNetters,



Here’s something I have not seen before.

I have seven different ‘theories’ for what’s happening here.

Three of which do not involve mythical creatures, illegal substances or the alignment of celestial bodies.



This capacitor is on a path that sees a lot of RF power.

The unit went through 20 cycles of -70C to +115C while at nominal power.  Temperature sensing suggests this device could be hitting 170C.

No, we normally don’t test to these extremes.

The PCB has ENiG finish and the solder is SAC.   This is normal SMT, no rework.



I think I know in general what happened, but I am surprised.

I don’t have an explanation for the formation of the big pocket on the right.

Has anyone ever come across any solder joints like this?



Thanks Steve for uploading the pictures (links below).



http://stevezeva.homestead.com/pockets_25.jpg



http://stevezeva.homestead.com/Pockets_CS.jpg



http://stevezeva.homestead.com/Pocket-left.jpg



http://stevezeva.homestead.com/Pockets-right.jpg





Best Regards,

Andy

Andrew C. Giamis

Senior Failure Analysis Engineer

CommScope

2601 Telecom Pkwy

Richardson, TX, 75082, USA