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From:
Wayne Thayer <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Wayne Thayer <[log in to unmask]>
Date:
Fri, 13 Mar 2015 15:31:10 +0000
Content-Type:
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Hi Howard,

I didn't mean to say that this NEVER happens with a cerdip...Indeed, the
nature of the structure is that the shock waves can break an epoxy seal
(never saw it with glass). But it should be a pretty severe shock required,
not mild rattling around in tubes. It's your second picture that clinched it
for me, which depicts a device sloppily made and wantonly abused.

The pix make it look like they were bonded with aluminum.
Interesting--that's what was used towards the end of the "cerdip era"
because the high temperature required for the glass seals would corrode the
Au/Al weld too much. Since these were epoxy sealed, that requirement isn't
valid. But maybe they changed lid sealing processes but not the rest of
their "approved" process to reduce re-cert costs.

Wayne

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Watson, Howard August
Sent: Friday, March 13, 2015 11:21 AM
To: [log in to unmask]
Subject: Re: [TN] Mechanical failure of 8-pin Cerdip

Drew,

Thanks for the feedback, and it is good to hear that someone has seen this
defect before with a cerdip. I was wondering if this type of problem might
be more prevalent with the cerdips.

Howard A. Watson 


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Friday, March 13, 2015 8:57 AM
To: [log in to unmask]; Watson, Howard August
Cc: [log in to unmask]
Subject: RE: Mechanical failure of 8-pin Cerdip

Howard,

Not common but it does happen.  I have witnessed this once.  When I was
working at Fisher Controls International.  This was in the pre ICT days.
Each assembly type had a custom made test box designed and built for it.
One of the test department folks called us out to see this.  He had  a
completed assembly on the test box.  The assembly was fully functional,
passed all set up and test process.  When he had finished test he noticed a
fourteen pin Cerdip missing it's lid.  Electrically sound.  We joked about
shipping it that way but of course off to repair it went.  Cerdips can fail
at the glue line if impacted hard or if the bond was compromised in some
fashion when it was made.  As long as it is very rare all you can do is
scrap the bad part or tube of parts if your uncomfortable with the risk on
the balance of parts in the tube.

Drew Meyer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Watson, Howard August
Sent: Friday, March 13, 2015 9:36 AM
To: [log in to unmask]
Subject: [TN] Mechanical failure of 8-pin Cerdip

Hello TechNet,

I have an IC Op Amp that was found in stock with the lid separated. The
stock room discovered this while kitting components, so this part was
minimally handled. It was stored in the original IC tube. Collectively, we
have never seen an occurrence of something like this, and I wonder if any of
you have experienced this before. The explanation I got from the
manufacturer is that it is most likely a packing and/or handling problem and
that if there is too much slack in the tubes, the parts colliding together
could cause the lid to pop off. Wouldn't the seal material be more robust
than to allow the lid to pop off? My concern is that we have 120 of these
all from one lot, and if there was a processing problem, then maybe I have
some other poorly bonded lids that may separate. Do you think my concern is
valid, or is this a one-off rare handling caused defect? These are space
grade parts.

Thanks to Steve, a couple pictures are posted on the links below. I don't
know what could be determined from the first picture, other than yes, the
lid definitely popped off! The second picture shows another IC with a lid
slightly skewed, but within tolerance I believe. Thanks in advance for any
suggestions you can offer.

http://stevezeva.homestead.com/RH1078MJ8-1.jpg
http://stevezeva.homestead.com/RH1078MJ8-2.jpg

Howard A. Watson


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