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.

Second Side Pinning with Guided Assembly

Guided Assembly with easy-wire 

Pin-Sight build aide. 

X    
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.

http://www.ipc.org

To purchase a copy of A620 visit the WHMA website.

X X X
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

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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-Pull


Pin-Sight 
Learn more about Pin-Sight

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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