Well I have an intermiitend problem with my GX20 and external flash. I have the Samsung 360 flash but there are times that when I attach it to the GX20 that they dont seem to know that each other are there, ie the flash doesnt switch to P-TTL and the shutter doesnt set to the flash sync and when I shoot, there is no flash firing. It can happen in any shooting mode, I usually shoot in apperture priority and have the iso set to my rear thumb wheel but even switching to P mode doesn't seem to help.
As you would expect, this usually happens when I am under pressure to get a group shot at a community meeting or convention and people are starting to think that I cant use my gear....
Any ideas or advice....and all kit is about 3 years old with minimal use