Pioneer SE-700 Headphones

(Vintage around 1974.) (AWESOME HEADPHONES!)
These had an interesting problem in that one side would be dead until you 'cranked' the volume up for a second.  After that, you could use them normally, but if you let them sit for any length of time, you had to jump them again.
 

This side had an intermittent connection between the ring and the mylar. You can see the old darker gray conductive ink that makes the contact between the outer ring and the mylar and the new lighter gray from the silver ink.