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February 2000

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Subject:
From:
"Stephen R. Gregory" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 22 Feb 2000 11:52:17 EST
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In a message dated 02/22/2000 10:16:22 AM Central Standard Time,
[log in to unmask] writes:

<< Lately I have been seeing failure analysis that indicates the failures
 were caused by trying to take a through hole component and bending
 the leads up and around or under the component body to make it
 a surface mount component.  In one case a crystal seal was broken
 and another the bends were just too "springy".

 Is there a set of suggestions as to how and when and IF this can be
 done to a through hole component?

 Susan Mansilla
 Technical Director
 Robisan Lab >>

Hi Susan!

Was this crystal a metal canned crystal? There are a lot of oscillator and
crystal manufacturers that form the leads on PTH clocks, oscillators, and
crystals so they can be surface mounted. But what they don't tell everybody,
is that you SHOULD'NT reflow them! They need to be hand soldered.

These are through-hole parts and just can't take the heat of reflow...just
call a few vendors and ask if they recommend reflowing the ones that are PTH
and converted to a SMT type of lead. Maybe that's where the seal was
compromised...during reflow?

Just a guess...

-Steve Gregory-

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