Tom,
We have recently used an 84 pin PLCC socket here, and in our application, I
have noticed the need to support the PC board directly under the socket when
inserting the part. If the board is not supported, it causes excessive bow
in the PCB. The reason for this in our application is through-hole leads,
mounting hardware, etc. holds the board up slightly from the surface on
which it is set. If the board is allowed to bow too much in the socket area,
I can see where it might cause a broken solder joint. I don't know if this
fits your scenario, but it's all I can offer. You also mentioned that the
socket bows out a little when the part is inserted, we see the same thing
here. Because the socket contacts are under constant spring pressure, and
there is a large span between corners, I think that will always be the case
with a socket of this size (unless the socket walls are made very thick).
Good luck,
Thomas DeSmit
EDA Librarian/Sr. Eng. Tech
IFR Americas
Wichita, KS USA
> -----Original Message-----
> From: TechNet E-Mail Forum. Thomas Han
> [mailto:[log in to unmask]@IX.NETCOM.COM]
> Sent: Tuesday, February 01, 2000 4:17 PM
> To: [log in to unmask]
> Subject: [TN] SMD PLCC Socket
>
>
> We ran a batch of boards that had surface mount PLCC84pin sockets. PLCC
> components are placed prior to shippment. Our customer have noticed that
> few boards had disconnected socket pins(one per socket). Only
> thing that I
> could think of that would cause this to happen is, installation of PLCCs
> into its socket, creating enough shear force on the connector to
> break the
> solder joint. I didn't get a chance to look at the broken solder joint
> itself, but I took a look at some of the finished goods in house, and the
> plastic housing on the sockets bow out a little bit upon
> insertion of PLCC.
> Has anyone seen this before? What else might cause this to happen.
> Customer had stated that the solder joints are well wetted. Any input is
> greatly appreciated.
>
> Tom
>
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