I think everyone has encountered this problem:
A device does not work anymore properly until you find out by coincidence a position in which it still works. For example my USB microphone has a faulty connection until I lift the cable slightly...then it works again.
I have now always assumed that it is a problem with solder joints and the repositioning reconnects the device. The problem is: After I bought a soldering kit some time ago (it is out of order, by the way :( ) I opened the microphone and was surprised that everything looked fine. The solder joints look solid and the cable itself did not show any marks or bends. Electrons should be kind of disinterested how the form of a cable or a connection is, so I am a bit confounded.
I suspect this question is a duplicate, but I did not find anything in this way.
What exactly are those problems which cause that devices/cables work only in specific positions (from most frequent to least frequent) and how can I fix them?