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Via Failure in Field

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#60771

Via Failure in Field | 6 January, 2010

Hello, we have recently had some products returned (they were installed and operating in the field for around 2 months before they were returned). After looking at the boards it seems the vias have failed.

We now have 2 pc pcbs with the same Via fault, all other vias on the pcb look Ok.

Attached are some pictures of the failure. Any information regarding possible causes is appreciated.

The vias that are damaged are connected to the same net (they are in series).

thanks, oddbudman

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kpm

#60778

Via Failure in Field | 6 January, 2010

what is the residue all over the board in the second picture?

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#60781

Via Failure in Field | 6 January, 2010

Via failure could be caused by cracks in the barrel, or thin plating, or fractures in the traces leading to the vias, . X-ray analysis could pick up a fractured trace and cross-sectioning of the vias could pick up the cracks and thin plating. Second photo with the solder "spike" could be a repaired solder joint and the residue on the vias could be excess flux. Surface of the vias in the second photo resembles corrosion.

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#60782

Via Failure in Field | 6 January, 2010

Looks to me exactly what flux does to a board when its not washed correctly. Seems to me that it could be someone did some rework and didn't wash the board? Or the board wasn't washed correctly in the first place? Just speculation though.

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#60791

Via Failure in Field | 7 January, 2010

Did someone repair that solder joint to the left of the vias with plumber's flux and leave the residue?

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#60793

Via Failure in Field | 7 January, 2010

did the boards get built by hand or via smt process (through reflow oven)? Someone asked earlier if some one touched up the adjacent joint. The answer to that question is yes. Look at how the solder tails off the smt pad away from that joint! I suspect the same as others. somone touched this up and used an agressive flux and did not remove it.how does the pad and part look that are adject to the damaged via's?

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