I've been using the Yongnuo YN-622N-TX flask controller with the YN-622N transceivers for a while now with no issues... until last night. There's a light on the transceivers by the hot shoe that's usually green. Well last night it turned red and they wouldn't fire. I have 2 of them and they both quit working. I tried changing batteries, changing flashes, turning on and off, nothing worked. The controller was set to manual so I could adjust the output of the flashes and the flashes (SB-600 and SB-700) were set to TTL. Why TTL? Because that's how they need to be set in order for the manual adjustments on the flash controller to affect the output on the flash units. The instructions with these things are terrible and I came upon that setup through trial and error and it's worked for almost two years now... Until last night. Can anyone help? Or does the red light mean "these are shot, buy new ones." I also tried this on 2 different cameras. A D700 and D750. These have worked flawlessly on both in the past.