Hi,
after some 40 years experience with guitar amps and accessories I figured I had seen every kind of fault possible with a 1/4 inch jack to jack lead. But I have now seen one more.
A high quality, hand made lead using Neutrik gold flashed plugs and Canare low noise guitar cable came my way with a request to re-terminate one end, as it was " faulty ".
Of course it checked out fine with an ohm meter and continuity buzzer, no matter what I did to the lead. Internal inspection of each plug end showed it was fine too.
Then I spotted something, the tips of both plugs looked rough and dirty - just the outer edges mind you. Under magnification, it was obvious both were gouged all around and had material embedded in the crevices. The gold plating had gone too.
Knowing that some jack sockets contact the tip right on its edge, it had to be cause of the problem the owner was on about.
WTF was the cause ?
The owner regularly busks, performing on concrete and tared footpaths.
If you drag a guitar lead across a surface, the EDGE of the tip is the contact point.
Don't matter a hoot with smooth surfaces or carpet.
... Phil