Sea&Sea YS-D2 TTL Problem with new J Version

So just for everyone who might have the same problem at some point: In the end I managed to convince the reseller that sold the strobes to contact Sea&Sea and have my strobes replaced. He wanted quite a steep fee for it, but alas at least now I have two new strobes that are working. The rep from Sea&Sea mentioned btw. that they have seen this problem before and it is known to them. So if you experience the same issues, don't waste time testing and contact Sea&Sea for a replacement.

Sea&Sea Strobe problem:  It sounds as if the strobe's trigger is off, such that it flashes a bit after the camera's shutter has closed, and the flash does not show in the photo.

The strobe's flash is controlled by a complex timing circuit that fires it for a defined length of time to control the brightness of the photo.  If this timing circuit is defective it may delay the onset of the flash, such that the strobe flashes is delayed.  It is a factory repair as the circuits are very complex and tightly packed, and can only be replaced by factory technicians. 

  This possibility can be checked by setting the shutter at 1/250 sec, the f stop closed at about f28. Set camera and strobe to M mode (for later pictures set to TTL).

 Now aim the camera (no housing), with the flash open, at a mirror, so the camera and strobe are reflected by it. Hold the strobe fiber-optic cable against the open flash, and take a picture: it should show the mirror reflection of both flashes. If it only shows the camera's flash, and the Sea&Sea strobe did flash, it may mean the strobe's firing is delayed by a defective internal strobe circuit.  If so, let us hope your local dealer can help.

Another diagnostic step would be to take a video while you fire the camera and strobe at a mirror.  This might show the relative timing of the strobes and camera's flash.  Good luck!