Inon Z-240 malfunction @ 50 m

I recently completed my Dsat deep tec course and had the chance to dive to 50 m, with my camera. My Inon Z-240 strobe failed at that depth, in a somewhat unusual manner. I would be interested if anyone else had a similar experience and knows of a solution to the problem. I would also like to find out if what I experienced is due to a faulty individual unit or due to a problem with that piece of gear in general.

I am using a Canon EOS 400D, in a Hugyfot housing, connected via 5-pin cables to an Inon Z-240 strobe. A second Z-240 is used as a slave. The malfunction was of the master strobe. I tested the setup on the surface, and the camera took pictures and the strobes fired, as they had during surface tests and dives during the previous days. At depth, however, after 3 or 4 pictures, pressing the camera shutter did not fire the strobe anymore. The control light was still on (red = charged), but the strobe wouldn't work anymore. Turning the camera and the strobe off, and on again, sometimes convinced the strobe to fire once, but not a second time. After a few minutes of fiddling with this problem I gave up and instead enjoyed the dive.

Surprisingly, when returning to the surface, back at the dive shop, after getting the setup out of the rinse tank, the strobe worked fine again, firing every time I took a picture. I assumed I had miss-set something (though there are not many ways to do that and I am quite familiar with this strobe) and readied the camera system for another dive.

At that dive, again to 50 m, the exact same thing happened: Flawless function at the surface, no firing at depth, again flawless function at the surface.

The Inon Z-240 is rated to 80 m. I had the connector cable break at a previous instance, but then it just did not transmit any signal anymore and had to be replaced. I don't think the problem described here is due to a cable problem.

I'd appreciate any suggestions why this problem occurred and how to solve it.

If you're certain the strobe isn't firing and it isn't a settings issue on the camera then I would think it would have to be the cables. The strobe itself is incompressible at that depth. There's no partial flood occuring because operation returns to normal at the surface.

I had a similar problem a week ago on a fairly deep dive luckily i have both my 220s hard wired .After putting my brain into gear i changed the faulty one to slave whilst still on the dive.

After i got out and back to camp i removed the cable cleaned all the contacts and and now it seems ok. I will know on this fridays dive if it was just a bad connection. I would agree the problem almost certainly will be the cable. I have got 4 of the Inons and have used them most weeks for many years, my opinion is they are bullet proof. Touch wood!

I thought I replied here but seems not. I would suspect it is not the sync cord but rather the hotshoe connector. I had the exact same issue as this just not as deep and it turns out it was the hotshoe connection that was a bit flaky. I built a foam wedge to hold the connector in place and it solved the problem. Clearly the aluminum part of the housing didn't compress at depth but the connection between the front and back of the housing clearly will change dimensions a bit and this was enough to cause problems.

Bill

Thanks everybody for the advice!

Klaus