Wireshark
Registered
Dear forum members,
I just joined the Scubaboard forum because of this interesting subject. My dive light is a NaturalShine Big Fish, sold by a Spanish company. Looking at the the pictures of the MagicShine MJ-850 and my own light, I'm convinced they are identical. I bought it last February on the BOOT fair in Düsseldorf, Germany, for a fair price, including a sturdy case. In July I used it on the first dive below 20 meters. After a while I noticed a little water inside, and I was able to tighten the glass retention ring with my bare hand. That must have worked as no new water came in. I kept it vertically during the rest of the dive to prevent damage to the electronics. Back on the boat I managed to remove the glass, clean and dry the internals successfully after which it functioned again. Till two weeks ago, when I switched it on and off for a short usage (on land). The next day it refused completely. Batteries were surely fully charged. There was no visible damage or corrosion caused by the earlier partial flooding. With the multimeter I measured about 13 mA standby current in off position, 15 mA in all other positions. So my conclusion is: there is still some electronic activity.
After reading this thread I conclude my light has a blue PCB marked MJ-284. Michael, does this failure mode also exist for the blue one?
I'm no trying to get a new LED & driver unit from the supplier. It is still under warranty. As a back-up plan I can replace the PCB myself. Micheal, I have the impression you sell them?
Some of my observations and experiences I would like to share with you all:
1. The replacing O-rings for the body I used are AS 568A-125 32.99 x 2.62 NBR 70 ShoreA
2. The O-ring behind the glass is metric 50 x 2.5.
3. I would not replace it with a harder one. This seal in an axial groove works best if there is no gap between glass and metal through which the O-ring can extrude under pressure. I tried to tighten the retention ring with the standard O-ring fitted to the same position as without, which was a hardly possible. Harder O-ring rubber makes it harder to close the gap.
4. Also, I see no reason to use a lubricant on this stationary seal. Lubricants should only be used on O-rings that experience a sliding or rotating movement from the counterpart.
5. I would not rely on the plastic cap on the back of the driver to pull the brass ring out. You may strip the thread off. Or was anybody successful using it as an extraction tool?
6. If anyone wants to make an extraction tool himself: the thread is a non-standard M29 x 1, so you have to find somebody with a lathe as I don't know any standard component (fitting) with this thread that can be modified for this purpose.
7. The tool I made to turn the retention ring is a 3 mm thick steel plate 53 x 30 mm with 4 edges fully rounded. clamp it in a vice, place the light on top and rotate the light. That's better and safer than using a pair of spread scissors.
Sape
I just joined the Scubaboard forum because of this interesting subject. My dive light is a NaturalShine Big Fish, sold by a Spanish company. Looking at the the pictures of the MagicShine MJ-850 and my own light, I'm convinced they are identical. I bought it last February on the BOOT fair in Düsseldorf, Germany, for a fair price, including a sturdy case. In July I used it on the first dive below 20 meters. After a while I noticed a little water inside, and I was able to tighten the glass retention ring with my bare hand. That must have worked as no new water came in. I kept it vertically during the rest of the dive to prevent damage to the electronics. Back on the boat I managed to remove the glass, clean and dry the internals successfully after which it functioned again. Till two weeks ago, when I switched it on and off for a short usage (on land). The next day it refused completely. Batteries were surely fully charged. There was no visible damage or corrosion caused by the earlier partial flooding. With the multimeter I measured about 13 mA standby current in off position, 15 mA in all other positions. So my conclusion is: there is still some electronic activity.
After reading this thread I conclude my light has a blue PCB marked MJ-284. Michael, does this failure mode also exist for the blue one?
I'm no trying to get a new LED & driver unit from the supplier. It is still under warranty. As a back-up plan I can replace the PCB myself. Micheal, I have the impression you sell them?
Some of my observations and experiences I would like to share with you all:
1. The replacing O-rings for the body I used are AS 568A-125 32.99 x 2.62 NBR 70 ShoreA
2. The O-ring behind the glass is metric 50 x 2.5.
3. I would not replace it with a harder one. This seal in an axial groove works best if there is no gap between glass and metal through which the O-ring can extrude under pressure. I tried to tighten the retention ring with the standard O-ring fitted to the same position as without, which was a hardly possible. Harder O-ring rubber makes it harder to close the gap.
4. Also, I see no reason to use a lubricant on this stationary seal. Lubricants should only be used on O-rings that experience a sliding or rotating movement from the counterpart.
5. I would not rely on the plastic cap on the back of the driver to pull the brass ring out. You may strip the thread off. Or was anybody successful using it as an extraction tool?
6. If anyone wants to make an extraction tool himself: the thread is a non-standard M29 x 1, so you have to find somebody with a lathe as I don't know any standard component (fitting) with this thread that can be modified for this purpose.
7. The tool I made to turn the retention ring is a 3 mm thick steel plate 53 x 30 mm with 4 edges fully rounded. clamp it in a vice, place the light on top and rotate the light. That's better and safer than using a pair of spread scissors.
Sape
