Last week I flooded my Inon Z240 with salt water. It was pure stupidity, I obviously did not grease the O-ring of the battery compartment properly, so it was twisted a bit when I tightened the cap, just enough to let water in. During the dive the strobe fired correctly, but showed some strange behaviour (target light being off for a couple of seconds after a flash, at the end of the dive target light still on after shutting off the strobe). When I came back to the dive center I could see the twist in the O-ring (must admit I could have seen it before, but ...), so I knew what had happened.
When I opened the battery compartment the infamous black liquid came out, and the batteries were heavily corroded. Another diver at the resort had some experience with such kinds of floodings. He washed the battery compartment, cleaned and dried it. After that the strobe was not functioning, but it was not completely dead. When turning on, the target light was shining, and there was a "crackled" sound as if the capacitor was was getting some charge, but it did not load completely. Seems that some gas that had built up during the battery corrosion pushed water or toxic broth into the strobe compartment, or the battery compartment is not sealed against the inside.
I had a S&S backup strobe, so I let the Inon alone for that night and put it into the (hot) compressor room. Next morning I tried again, same behaviour. I saw that there are some tiny screws in the front of the strobe. I removed them and could lift the front plate of the strobe (I had to pull a bit to lift it off the o-ring seal. If you ever have to do so, don't use excessive force, since the onboard sensor sits in the plate and is wired). I let it rest for twelve hours in the air-conditioned camera room, hoping that all water/humidity inside the strobe would dry. Guess what - after I reassembled the front plate the strobe worked perfectly again up to the end of my trip! Of course I will let it have serviced now.
This is just an info that not necessarily everything is lost once there is water inside the strobe compartment, but of course I sincerely hope that no one will never have to make use of this knowledge for him-/herself or some fellow divers!
p.s.: I just found out that a dealer in Germany offers an O-ring which is placed inside the top of the battery cap for additional safety. Costs just a few Euros, but that would have been a good investment...
p.p.s.: Does anybody have an Inon repair or service manual? Would have been a great help if I coud have opened the strobe completely, which I did not dare to do in fear of ruining sensitive parts.