MJ850 - cheap. Too good to be true?

[Laurent Gluck]

Laurent,

Indeed you have to remove the reflector. Simply unscrew it. First remove the cap at the back and the batteries. Next mark position of the ring that retains the glass, as during re-assembly, you must be sure to tighten the ring to at least the same position. Remove the ring with a tool (steel plate 53 x 3 x 30 mm, with full rounds at two corners) Remove the glass, if it adheres to the O-ring, gently blow on the back end. Then unscrew the reflector. There are two notches in the outer edge for this purpose. Underneath you'll find another, smaller retention ring that holds the LED and driver unit inside the light body. There is also a plastic washer around the LED that prevents a short circuit between the LED power supply caused by the reflector bottom. After you removed this unit, unscrew the black cap. You have to make an extraction tool with M29 x 1 that fits the brass bushing. Also cut a piece of tube that fits around the driver unit. With a threaded rod M6, a couple of M6 nuts and big washer you are able to extract the brass bushing with the PCB inside. Next, you have to remove the soldering that binds the PCB to the bushing. Also disconnect the wires between LED and PCB. Pry the LED up from its seat and the heat conducting compound, otherwise your soldering iron can't heat the joint sufficiently. When assembling make sure you put sufficient heat conducting compound underneath the LED and between driver unit and lamp housing.

Good luck,

Sape

Thank you Sape for your help!

Regards
Laurent

 

[mifriend]

Hello all,
thanks for interesting comments: I experienced flooding and had to change the LED + Driver: where did you find yours? (the one I got from Magicshine looks less powerfull !
I am going to add sealand paste to avoid new issue.
Do you think it is a good (or stupid) idea?
thanks for your replies
Michel

 

[Wireshark]

Dear all,

See attached pdf for the brass ring extraction tool I made. All is made of mild steel. The tube is a standard available size. Any other size will do as long as the ID is between 33 and 35 mm. Have fun.

Sape

 

[Tapazou]

Does anyone knows what is written on the broken part (chip identification) of blue pcb. It might be easy to repair with stronger part...

 

[StuartT]

I just received the MJ-876 from Novae and will post it's reliability once I get it in the water.

 

[Spg01]

I received mine in November and have had it on a bunch of dives with no problems. It replaced my SST-50 that was having battery issues. The light is on the large size compared to the SST-50, mostly because of the battery pack that is inside the handle. But according to Magic Shine there is a balancing circuit in the battery pack which is a great feature. I usually only do one night dive at a time and it always lasted through the entire dives running 1 hour+. I would like to build a handle for it, but I am not sure how well it will work with the light being kind of large.

 

[Wireshark]

Does anyone knows what is written on the broken part (chip identification) of blue pcb. It might be easy to repair with stronger part...

Tapazou,

That will be a hell of job, replacing the broken part. It is only half the length of a rice grain. You definitely need steady hands and eagle's eyes. I already searched for the four letter identification that you can see on the picture elsewhere in this thread. I only found a Russian forum discussing the same problem, but not offering a solution. I guess it's a transistor.

Sape

 

[Wireshark]

Dear all,

Just want to inform you that I succeeded getting new LED units from the factory at reasonable cost (UPS shipping charges). I explained the problem and kindly asked for two PCB's to repair my buddy's torch and mine. Instead I was offered two complete units. The processing took a while, but it was worth waiting. Magicshine has a PayPal account, so payment is no problem.

I'm a happy diver again and I can only recommend others to follow the same route to get their light fixed. Good luck!

Sape

 

[Tapazou]

The chip number is AGDF 92. It's not easy to replace, but it's possible.

 

[yegoshin]

Ok so since a special tool is needed to get the driver out, & shipping from US to EU is, to say the least, inconvenient. How many people in the US have a broken MJ-850, & still need the tool the replace the driver? I'm thinking a group buy on the proper drivers from MagicShine then everyone here can USPS the LED module to get the drivers replaced super cheap, I guess we'd have to know the cost of a complete LED module vs just the driver to see if its worth getting a tool made up.
Here is a nice set of instructions in russian with pictures: Ðåìîíò ôîíàðÿ äëÿ äàéâèíãà MagicShine MJ-850 Ìàãàçèí "Çàïàñ Ìîùíîñòè"

-Dmitriy