So I returned from my dive holiday (which was great!) with a defective MJ850 torch.
How and what happened
During my last nightdive on the liveaboard, I had a buddy with me that was not really too confident in nightdives. I decided that if I would use my light, set to maximum power, it would be a bit easier for the buddy to dive.
Setting the MJ850 to 100% power creates blind fish, atrackts lionfishes from 200m distance and burns holes in coral. It is that bright! Until this dive I had been using the minimum setting, still overpowering all the other divelamps of the team.
Seeing the light it produced I decided to throttle back a bit to the medium setting, and since this was the last dive onboard decided at the end of the dive to reset to maximum power for the last 15 minutes of the dive or so... I had not tested the lamp that much, yet.
Nearly back at the boat (the MY Rosetta) the light suddenly dimmed to something comparable to my backup. Returning to the boat the 5% light is more than enough, as the Rosetta uses it's floodlights during the nightdives. Initial thoughts: the batteries must finally have reached a minimum level. (I actually recharged the batteries only once during this trip... and only because I figured not to trust the battery indicator.)
Back on board I was not able to turn the MJ850 off. It remained on, in emergency power setting, during the fresh water soak.
The MJ850 is now, still, burning at 5% emergency power as soon as I reconnect the batteries. I tried the obvious... shaking it a bit, leaving it on for a while, turning the magnetic switch ring to all different settings possible. Still no solution.
I am now in a mail/msn discussion with the company in China, to see if I can send this lamp for repairs. With no real foothold in Europe for the company, this will obviously be an expensive exercise for me and for them... hoping I can trust the repairs to be made and the lamp to be returned in time for my next dives.
Anyway .. the answer to my earlier questions on Scubaboard: MJ850 cheap. Too good to be true? might now actually be answered... cheap! and too good to be true (at least if the warranty and service does not really work out.)