The end cap photos are 500X mosaics, cross-polarization, no oblique lighting.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Giamis, Andy
Sent: Wednesday, September 06, 2017 1:20 PM
To: [log in to unmask]
Subject: Re: [TN] Crazy Solder
Thanks Leland,
The stereoscope is a Wild M3Z (image @ 25X, light pipes and Styrofoam cup filter) The rest are on a Nikon Eclipse ME600 with light pipe back lighting (100x mosaic) and different degrees of cross-polarization.
The stage is a motorized stage with x, y and z actuation.
The software is Clemex professional: image and stage control.
I used extended depth of field and mosaic construction features.
I confess that the lighting is not even in each field. I have a darker upper right corner that I just can't get rid of. It shows in the mosaics.
-----Original Message-----
From: Leland Woodall [mailto:[log in to unmask]]
Sent: Wednesday, September 06, 2017 1:13 PM
To: [log in to unmask]; Giamis, Andy <[log in to unmask]>
Subject: RE: Crazy Solder
Andy,
I can't answer your questions, but those are some incredible images! Could you perhaps share the equipment and magnification used to capture these?
Thanks,
Leland
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Giamis, Andy
Sent: Wednesday, September 06, 2017 12:25 PM
To: [log in to unmask]
Subject: [TN] Crazy Solder
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
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