PCB Open Circuit

[T34 Flyer]

What do you guys think could have caused this PCB short out?  Dry location and 7.5 Amp load each side.  It is one of my oldest 4 controllers.

[TheDucks]

If those go to those black wires, you had a solid short. Was the PCB on a conductive surface, OR did a stray screw roll under the board at some time (I would expect to see a bit of carbon on whatever made contact

The only other idea, is whatever is on the other end of those wires (pigtails) has become rust/carbon tracked inside the end . Ohmmeter (2M scale) might show that.