workmanship problems pictorial reference
Pictorial Reference - Printed Wiring Assemblies
Pictorial Reference - Printed Wiring Boards
Pictorial Reference - Components
Pictorial Reference - Fiberoptics
Pictorial Reference - Wiring and Cabling
Pictorial Reference - Wire Bonding External Link
inspection pictorial reference
workmanship training

Guidance and Advice



WORKMANSHIP PROBLEMS PICTORIAL REFERENCE

 

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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