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Subject:
Re: Wisker growth on PCBs
From:
"George Franck Jr" <[log in to unmask]>
Date:
Thu, 7 Nov 1996 15:53:16 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (84 lines) 
Rolf,

EDN 9/5/79 page 59 - Technology News 
EDN 4/20/80 page 63 - Technology News

George Franck



On Nov 7,  3:26pm, Rolf Ehrat wrote:
> Subject: Wisker growth on PCBs
> Dear Colleagues,
> 
> I am writing with respect to a 4 layer (mixed technology) PCB with the
> following layering:
> 
> Component side traces
> Ground plane
> Vcc plane
> Solder side traces.
> 
> We have, on three occasion, had boards burn out after the boards were 
in
> service for some time. The burns are between the 12V battery traces 
and
> other traces/planes. The 12V is fused with a 1.5V quick fuse. The post
> mortem on one occasion indicated that the short occurred between a 
component
> pin and the ground plane. The other cases are not so clear as the 
short
> occurred on an inside layer along an edge of the board. The spacing
> generally is 0.015".
> 
> I recall to have read in the past about wisker growth. Can anyone 
point me
> to such literature, preferably in EDN, Electronic Design. Any help 
would be
> appreciated.
> 
> 
> Rolf Ehrat, Sen. Des. Eng.		Tel. (905) 669-2280 ext. 320
> Scintrex Ltd.				FAX  (905) 669-5132
> 222 Snidercroft Rd.
> Concord, Ont.
> L4K 1B5
> 
> 
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> 
>-- End of excerpt from Rolf Ehrat



-- 


George Franck Jr
Raytheon E-Systems
Product Assurance Engineer
Falls Church Va

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