seems as being a trouble in one or many vias. We  had similar problems many years ago. Reason was unsufficient metallisation to connect via 'tube' with lateral copper layer. We repared with crazy but functioning method: pressed a piece of metal in vias with open circuits, and they worked again. Not recommended for longlife products.

Ingemar Hernefjord
Ericsson Microwave Systems

-----Original Message-----
From: McGlaughlin, Jeffrey A [mailto:[log in to unmask]]
Sent: den 21 september 2000 21:26
To: [log in to unmask]
Subject: [TN] FW: PCB FAILURE AFTER TEMPERATURE CYCLING


> !!!HELP!!!
>
> We are experiencing a strange failure in a circuit board and I hope
> someone can point out the failure mechanism.
> The boards in question fail with trace opens when cold, heat the pin with
> an iron and the open trace reconnects. The boards in question are 0.093"
> thick Getek, 6 layers (4 rout - 2 planes), with 0.015" trace and 0.010"
> spacing (we ain't talkin' high tech here :<) ). We have sectioned the
> holes in question and see really clean plating and pad junctions, no smear
> or nai-heading. Any suggestions as to cause?
>
> Jeffrey A. McGlaughlin, C.I.D.
> Sr. PCB Designer
> Battelle Memorial Institute
> Columbus Ohio
> [log in to unmask]
>
>

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