Got some more... and certainly the root cause. I made a sketch (jpg) if
anyone wants to
have a look.
The capacitor is a 1812 CC.
The boards are subjected to physical stress because of the
installation/removal of two
connectors. What is the problem here is that there is three mounting holes
for standoffs.
Therefore, the boards can be bent.
However, let's change my original question again:
Would anyone replace CCs for TH caps considering that a large number of
boards have
to be modified. Did anyone tried it before and with what kind of success
(or else).
I guess that the answer is pretty obvious... sorry for spoiling some time
here!!!
Then again I did not have all the information then.
Thanks!
-----Original Message-----
From: ME Magnin [mailto:[log in to unmask]]
Sent: Thursday, February 13, 2003 10:11 AM
To: [log in to unmask]
Subject: Re: [TN] TH capacitor on SMT pads
I cannot beleive that this wrong design explains capacitor cracks?
We have not received the answer to the question : which package is this
component (0805, 1210,1822, ...)?
Are all the components affected or just some of them (which distribution on
the layout)?
Because I met such a problem a few years ago (20 caps per board cracked in
the field on 2000 boards)I would look at following manufacturing steps :
hich soldering process : reflow or wave ?
how are the boards depanellized? (how far from the board edge are the
components? are they parallel to the edge or 90°?)
is a test performed on a test fixture with test probes ?
is a component inserted on a socket?
is the board clipped into a suport?
best regards
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Bissonnette,
> Jean-Francois
> Sent: jeudi, 13. février 2003 15:45
> To: [log in to unmask]
> Subject: Re: [TN] TH capacitor on SMT pads
>
>
> Nope! It was not missed... I picked it up and I was told
> that I was making
> a fuss for nothing, "...capacitors are
> holding well, we keep it like this...USE AS IS".... 5
> Face (for the
> terminations that is...)
>
>
> -----Original Message-----
> From: Kathy Kuhlow [mailto:[log in to unmask]]
> Sent: Thursday, February 13, 2003 9:51 AM
> To: [log in to unmask]
> Subject: Re: [TN] TH capacitor on SMT pads
>
>
> What type of end termination is on the cap? I assume a 3 or
> 5 face. Wow,
> how could this have missed or unnoticed?
>
> Kat
>
> >>> [log in to unmask] 02/13/03 08:17AM >>>
> I got one more info that may confirm the source of my problem,
> maybe some of you can confirm.
>
> The lands for the capacitors are too close together and probably
> not wide enough. Seems like the land patern is so that it fits the
> cap's width and the end comes flush with the cap at the ends.
> Results, there is no solder fillet neither on the end nor on
> the sides.
>
> Any thoughts?
>
>
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