Originally Posted by Leigh B
Yeah... What he said ^^^.
Capacitor failure is extremely common, almost guaranteed if the flash is more than ten years old.
It's an easy fix (replace the capacitor), but may not be worth the cost depending on the size and quality of the unit.
Yeah, what they both said ^^^.
The issue is that you get up to 80% full charge, maybe, just enough to flash. But not the right amount of light to use the chart for proper exposure.