Causes of Bad Connections

Causes of Bad Connections

Bad connections caused by… Countermeasure
/ Process Change
Could be detected in tests as…
Open Intermittent Open High Resistance
Wire not connected, missing or connected to something else (miswire): Guided assembly can help prevent miswires. Cirris provides multiple options for guided assembly.

Pin-Sight build aide.

Flux on mating surface of contact Learn more about flux on contact surfaces. X X X
Cold solder joint IPC/WHMA 6-20 section 4.3 to 4.9 has excellent information on soldering.

To purchase a copy of A620 visit the WHMA website.

Wire insulation caught in a crimp termination. Inspection and adjustment for cutting/stripping equipment including replacing stripping blades. X X X
Metal oxides on surface of joined metal parts including failure of gas tight connection. This can be a field problem that is difficult to test since the wiping action of connector engagement usually interrupts the problem for a short time. To learn more about this problem see:

Dry Circuit Testing

Deformed/damaged/worn contact, including fatigue in spring force of contact. Contacts in mating fixturing connectors that are identical or even undersized may help. Spring probes are blind to these faults. X X X
Failure of contact to fully mate because contact is not retained in connector housing. Contact Retention Problems
See Push-Click-PullPin-Sight
Learn more about Pin-Sight
Wrong wire gauge for termination. Check manufactures specifications for terminals/pins against wire guage. Use a splice to change wire size. X X X
Loose crimps, including those caused by missing strands of wire. Crimp force monitoring, Crimp Pull Test:Crimp Size Chart X X X
All strands broken (sometimes the result of excessive crimp force). Crimp force monitoring, Crimp Pull Test:Crimp Size Chart X X X
Fixturing to the device-under-test has any of the problems above. X X X