Reply-To: "Fred Bartoli"
From: "Fred Bartoli"
Subject: Re: PCB puzzle
Date: Sat, 28 Sep 2002 21:24:10 +0200
X-Newsreader: Microsoft Outlook Express 5.00.2919.5600
Organization: Guest of ProXad - France
NNTP-Posting-Date: 29 Sep 2002 10:35:52 MEST
"John Woodgate" a écrit dans le message
> I read in sci.electronics.design that Spam Hater
> wrote (in <firstname.lastname@example.org>) about
> 'PCB puzzle', on Sat, 28 Sep 2002:
> >I have seen "whiskers" grow inside a PCB. There is a contaminant in
> >the PCB, and your heating cycle is causing it to move around inside a
> >tiny crack in the substrate.
> >Lapping down an un-assembled board would show nothing. The
> >contaminant was probably introduced in the assembly process, and the
> >lapping process closes the cracks.
> It should be possible to find out for sure. In fact, if you have ISO
> 9000, I think you MUST find out for sure. The methods (in order of cost)
> are probably:
> Crack detection fluids
> NMR (if your local hospital will co-operate)
He he, just eat the board, and maybe you'll get it for free.
> Regards, John Woodgate, OOO - Own Opinions Only.
> Interested in professional sound reinforcement and distribution? Then go
> PLEASE do NOT copy news posts to me by E-MAIL!