The photos uploaded without web address: to be fair to the copyright owners - 1st photo from daveharasti.com/nelsonbay/cowries/Volva_volva1.jpg and second from i.pinimg.com/736x/5c/7c/34/5c7c34fbb5ff531261e527d64cf25472--volva-snails.jpg
So when you mentioned on a dive that you had the problem and shutter release was locked up. Did you change your strobes back to manual during that dive? I just want to make sure that if TTL misbehaved, at least going back to manual would be a good back up. However, if the board decided to act up and there was no way to get around it while on a dive, may be it is not worth bothering with it, I guess.
Hi -- this happened before diving and I dived cameraless!! I can only assume it was a circuit board issue as when I tried a nikon external flash everything was fine. After a third attempt at home with the strobes they started firing normally - beats me but it was very annoying. With the switches on the board both are down - down for inon on left and down for TTL on right. The fact that TTL switch is on does not (as I understand from reading here and elsewhere) preclude the use of manual settings.
On the inons I just turn the strobe dial straight to manual. When I use TTL on the strobe, despite the fact the ttl converter itself is lighting to confirm TTL (green light) and the strobe itself has TTL confirmation light (green as well I think) the shots are always badly underexposed. I am not having that problem in manual mode, but it did not matter what I did on the weekend, nothing worked, despite trying all switch settings, changing the batteries etc, I will have to use trail and error over the next few days and if the problem persists I will reinstall the original flash trigger and send the TTL one for repair / replacement as it is under warranty.