Not sure if it's the same reason, but...
Many, many years ago, shooting with a (very manual) Vivitar 283, the flash fired but with a very loud pop. It would continue to charge, but wouldn't fire, using either the test button on the back or triggering it by firing the camera. It sat for a week or more (key point here*) before I could do anything with it. I took it apart (I was always tinkering with things as a kid) to find a wire had come off the circuit board. Soldered it back on and the flashed worked like before.
* the reason I mention that it sat - when it stopped firing, the capacitor was at full charge, something I believe in the 500 volt or higher range. Had I taken it apart right away, I would've risked serious injury playing around with a full cap. So if you do decide to take it apart, let it sit without batteries for a week or more to let the cap discharge!
Again, might not be the reason yours stopped firing, maybe someone else here will have a better idea.