It didn't do its job very well!! Sam had a bout of uncontrolled feedback and the tweeter blew..
I wonder, the PTC was glued to the circuit board with hot melt glue, would it not be better if it was in free air. The copper circuit board could have been acting like a heat sink.
The winding of the tweeter speech coil is a flat conductor, it measures 0.02mm x 0.5mm, which if I am correct is equivalent to .02mm which as a fuse, is at a pure guess, probably about .1 amp, times 25 as it is 25 times thicker in the other dimension. This makes the speech coil wire able to carry 2.5 amps....
Have I worked it out right??