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Hi David,
Sorry about not getting this posted earlier, but I have not been feeling
well today, and just got around to checking my email. I have your picture
posted now though:
http://stevezeva.homestead.com/discolored_leads.jpg
I think what guy was referring to was a thread from a while back that I
started about a purplish tint that I saw with some SAC305 solder on a gold
plated board. Here was the picture:
http://stevezeva.homestead.com/Trippy_Solder.jpg
George Wenger was interested in analyzing it for me, and this was his
report:
http://stevezeva.homestead.com/FSC-5178.ppt
But what I see with your caps is different I think. The purplish tint that
you are seeing maybe some of same sort of oxide that was in the SAC305
solder that I saw, but I find it hard to believe that the manufacturer would
ship tantalum capacitors looking like that. I've seen many, many reels of
tantalum capacitors, and I can say that I've never seen them come from the
manufacturer looking like this. Do these happen to be Vishay?
One of the things that come to my mind is that these may be counterfeit.
They almost look like they've been pulled off boards. You say that they're
straight out of the manufacturer packaging, but where did you actually
purchase them from?
Just from the picture, I would be suspect of these parts...
Steve
-----Original Message-----
From: Guy Ramsey
Sent: Thursday, March 08, 2012 10:36 AM
To: [log in to unmask]
Subject: Re: [TN] Discolored Leads on D-Case Tantalum Caps
Hi David,
Steve is out today, not feeling well. He may monitor his mail.
But, there was a thread a couple of weeks back about tin and purple tint on
the surface of solder.
It might be of interest.
Guy
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Bealer
Sent: Thursday, March 08, 2012 9:32 AM
To: [log in to unmask]
Subject: [TN] Discolored Leads on D-Case Tantalum Caps
I have some tantalum caps that the leads are so discolored (a brown to
purple tint to them) that the pick & place vision system is rejecting all of
them. these are supposed to be 100% Sn plated, are MSL 3 rated, and these
are new parts straight out of the manufacturer's packaging with no signs of
breach. The leads also will wet out using solder paste with OA flux.
If I can get the machine to place these what reliability issues could we be
facing?
I have a picture of several parts that I'll ask Steve to post.
David Bealer | SMT Department Manager
Phone: (217) 442-0611 ext. 6022 | Fax: (217) 477-7134
Watchfire Signs by Time-O-Matic Inc.
[log in to unmask]<mailto:[log in to unmask]>
www.watchfiresigns.com<http://www.watchfiresigns.com/>
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