Are these parts too close to any larger parts or ground plane that
could upset the thermal balance? Is your paste deposition and part placement
dead on? Is your paste fresh? If your answer is no to first and yes to last
two questions, then I would suspect your profile to be the cause.

> -----Original Message-----
> From: Jorge A Rodriguez [SMTP:[log in to unmask]]
> Sent: Friday, September 03, 1999 3:57 PM
> To:   [log in to unmask]
> Subject:      [TN] Tombstoning
>
>           I am having a lot of tombstoning with  1206 plastic film
> capacitors
> (stack metallized film) part numbers  ECHU1H392JB5 and ECHU1H123JB5 from
> Panasonic. Pad design was already checked and it seems alright.  From all
> the
> chips on the board, these are the only ones that  we are having problems
> with.
> Also the oven profile it's OK too (we are using a Unitherm Vitronic
> convection
> oven and Kester 256 no clean solder paste).  One think I noticed it's that
> the
> components seem to be lighter in weight compared to the  ceramic
> capacitors.
> Has anyone had a similar experience? , what can I do to improve the
> process?.
>
>                Any comments/suggestions. Any information is appreciated.
>
>
>                Thanks
>
> Jorge Rodriguez
> Conexant Systems
> [log in to unmask]
>
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