If you let the flash charge and run for a while without flashing it, the capacitor might re-form and the flash begin to function normally.
Sometimes the capacitors will come back to life, more often they don't. But it's worth a try. I have an old Honeywell from the early 60s, if I let it sit without use, the capacitor loses it's form. Charge the capacitor for a while, and the flash functions normally; I use it as a slave.
Well, I dit exactly the same with two screwdrivers when I still was at school. I learned my lesson...
Originally Posted by mr rusty
But you are right: Everybody be warned fiddling around with high-voltage capacitators!!
Safety is always a paramount concern when dealing with high-voltage equipment.
Even a small capacitor in a camera-mounted flash can store enough charge to kill a person.
If you're not familiar with proper methods for servicing high-voltage equipment, don't try it.
To discharge the capacitor I use a low end Fluke DMM (model 114) and in their low end models they have what is called a Low Z voltage mode which the impedance of the meter is only 2 KOhms vs the normal 10 MOhms impedance. It would discharge the capacitor safely, reasonably fast and also tells you what the voltage is.