Shawn NH

I recently had a similar experience with my YN560 IV and YN560-TX. I have had all these for years and had used all of these with my Nikon system (D750 and D7200) pretty successfully. I recently I attempted to use them on a Sony (A7r V) and found a similar problem to what was reported here. The first time I hit the shutter, the YN560 IV would trigger, but not the second time. Adjusting the exposure on the YN560-TX enabled me to trigger the flash again. I happen to have 3 YN560 IV units, and I attempted this with each one of them. Turns out the issue is strictly with only one of the YN560 IV units, the other two work flawlessly. My guess is that there is a difference in firmware with that one unit (not sure if it's older or newer). I hope this helps someone else get to the bottom of their issue.