Hi Paul,

Are these bare boards or have they been assembled?
Has anybody checked them out on an x-ray machine?

Hans

Air Force Material Command - We keep them flying!
~~~~~~~~
Hans M. Hinners                                 WR-ALC/LYPME Bldg. 640
Materials Engineer                                      380 Second Street,
Suite 104
Manufacturing Eng. Sec.                         Robins AFB GA 31098-1638
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> -----Original Message-----
> From: Chalmer, Paul [SMTP:[log in to unmask]]
> Sent: Friday, June 11, 1999 03:53
> To:   [log in to unmask]
> Subject:      Re: [TN] from jpl
>
> Here is some additional information on the suspected manufacturing problem
> from NASA:
> ***
> we have some circuit boards that have developed open connections when we
> apply pressure, heat or vibration.
>
> we destroyed one of the boards to create these cross sections.
>
> 40% of the via connections on one layer developed problems as depicted in
> the cross section photos.the cross sections illustrate the anomalies.
>
> the boards were designed to mil-275 (ipc 2221).
> material fr4 .093
> smallest trace is .008 air gaps .005
> 12 layers
> vias are .025 pad / .010 hole / annular ring .0075
>
> four of six parts look to have  failed.
>
> ron

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