I am baffled but, I have an idea of what is causing this. Camera fires fine, add a hot shoe mount flash and the flash won't shoot. The on camera fill flash pops up when you hit the button but, it won't go back down without manually pushing it back down.
I am wondering if maybe the fill flash is stuck and is overriding the hot shoe mount causing the HS flash not to fire.
At one point this morning the HS flash was firing, even when I wasn't hitting the shutter button. It just fired of a sequence of about 6 flashes.
Any ideas or suggestions?

