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Subject: Re: [Homebrew_PCBs] Jumping chips

From: "leon Heller" <leon355@...>
Date: 2009-04-04

----- Original Message -----
From: "Jim Lewis" <jim.lewis@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, April 04, 2009 12:12 AM
Subject: [Homebrew_PCBs] Jumping chips


>I have a problem with SMT chips jumping off the board during reflow. I
>preheat for 2.5 minutes 1/4" above the hot plate and then reflow 1.5
>minutes directly on the hot plate at 375F with a cover. Paste is from
>Stencils Unlimited. Any solutions?

Your PCBs might have absorbed moisture if they have been left around for
some time.

Leon