Power adapter sparks and then stop working
Judging by the discussion in the comments:


The flash comes out of the socket during insertion.
The socket works for other appliances.


The most likely explanation is that there is a dry or broken joint between the plug pins and the circuit board. The pins are going to take the most mechanical abuse. The spark may be escaping through the gaps in the case around the pins.



Figure 1. Check the PCB for dry or broken joints. Note the discontinuity in the solder bead compared with the adjacent pins. Source Pink Fish Media.