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Printed Wiring Assemblies (PWAs)
Solder cup cold solder joint failure
During a repair activity a cold solder joint was
made between this solder cup and the wire soldered into
it. Subsequent vibration resulted in the joint breaking
and the wire coming out of the socket
The failure of the solder joint could have also been
caused by contamination in not cleaning out the old
solder prior to re-soldering the connection. In addition
gold solder cups require 2 tinning operations prior
to initial soldering to eliminate the possibility of
gold embrittlement.
Reference
:
NASA-STD-8739.3
7.3 Preparation of Printed Wiring Boards, Terminals,
and Solder Cups
2. Terminals and solder cups shall be examined for damage
and cleaned prior to the attachment of conductors. Terminals
and solder cups shall not be modified to accommodate
improper conductor sizes.
5. Tinning of Conductors.
c. Gold plating on all surfaces that become part of
finished solder connections shall be removed by two
or more successive tinning operations (solder pot or
iron), or by other processes demonstrated to have equivalent
effectiveness.
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