In addition to locating a reel of bad caps you brought up another important
issue. Functional test is far from a really good test. Sometimes it covers a
lot, sometimes very little.

ICT actually does a really good job on the passives. 

Bob K.
 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Rivera, Raye
Sent: Friday, April 08, 2011 10:55 AM
To: [log in to unmask]
Subject: [TN] Cracked ceramic capacitors

Hello Technetters,

We had an issue with cracked SMT ceramic capacitors causing boards to fail
functional test. We isolated the problem to a reel of parts that contained
some cracked caps and purged these. Problem solved.

My question is about what to do with boards built with these capacitors
before we purged. The boards pass functional test. The concern is that a
cracked cap was loaded, but has not yet failed. The range of actions
proposed here are:

- Temperature cycle the boards between -5 C and 55 C a few times. The theory
is that this will flush out any latent defects.

- Visually inspect for defects.

- Manually change out all the suspect caps, about 50 per board.

Does anyone have thoughts on what would be the best method or another idea?
We don't have ICT capability.

Thanks!

Raye Rivera



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