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October 1999

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Subject:
From:
"Sauer, Steven T." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 11 Oct 1999 15:53:19 -0400
Content-Type:
text/plain
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text/plain (29 lines)
Susan,
As the others have stated, it is highly unlikely that the adhesive changed
states and flowed into the crack region of the component.
I have experienced the anomaly that you describe.  The root cause was
excessive down force during placement of the component onto the PCB (one of
the PCB supports was not properly installed into the tooling plate and
caused the board to bow up).  During the subsequent cure process, the
adhesive flowed into the crack of the component and visually covered the
crack (a double dot of adhesive was used).  During ICT, a high resistance
measurement flagged the component and upon removal, the crack was found.

Steve Sauer
Mfg. Engineer
Xetron Corporation

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