Roger I've hit this problem once in a big way too with a contractor :

Once they smd'd the top side;
than they've had this super new wave fully glass (no name, for peace)
enclosed , with state of the art spray fluxer ,
for second pass pth mount .

When i saw the top glass of the wave enclosure (with deposits of flux
despite rigid daily maintenance) ;
me the part time Dr. Watson  knew immediately why my microsockets behaved as
you described ;
they were misted from top !
Made them to work with outline pallets , cut the spray down , etc.
(in the process discovered it worked two ways ; misting from top ; and
overly keen forced creep of flux up from legs onto contact formation)

One of the many reasons why i stick to foam like glue ; call me plesiosaurus
or not .

The contacts are designed and validated to live quite happily clean & dry ;
without "enhancers .
My guess is yo're on no clean with flux all over ; doing it's corrosion
overtime .
Correct me if 'm wrong please .

paul

-----Original Message-----
From: Roger Hill (home) [mailto:[log in to unmask]]
Sent: Monday, 13 March 2000 3:52
To: [log in to unmask]
Subject: [TN] IC Socket Contact Quality


I am having trouble with our equipment.  Field service techs think there are
periodic glitches which lockup our equipment, due to the contact quality
(tarnish, dirt?) between ic's and there sockets.  They are able to reset the
system by pulling out the ic and reseating.  The problem then can't be
duplicated.  We have thousands of these in the field - so soldering would be
very very expensive.

To date, the field techs have also been burnish the ic leads once they are
removed.  Can this damage surface of the contact?   Is there anything else
we can be doing?  We have tried some "contact enhancers" but have had
problems with it attacking the plastic ic socket so we are reluctant to go
in this direction.  Any ideas?

Thanks in advance

Roger Hill
972-245-2243  x203

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