Infinity Ultra; common flaw?

I recently bought a Gerber Infinity Ultra, the first had an LED that was crooked so I returned it for a better centered one.

This new one has a way better, whiter tint than the original, so I traded up for sure. However I'm experiencing a minor annoyance with it. Every now and then I'll twist it on and nothing will happen. Giving it a good whack turns it on, but never completely solves the problem, eventually I will experience this again and have to whack it again.

Also, it occasionally flickers and sometimes will go out...again, a whack solves this.

Obviously some connection is being lost, like the battery contacts are not touching. The battery is in there pretty snugly though, so is this a common problem I can solve? I keep checking inside and the spring contact on the inside looks maybe a little compressed, but when I put the battery in, I can push it down a bit so the spring isn't crushed. The cap spring is fine, it was a teeny bit bent, but I straightened it out.

The only thing that looks suspicious that I can't really get at is the white ring of what looks like epoxy glue. It might be tapered a bit and preventing the battery's + end from making perfect contact with the spring in there.

Is this a common issue with Gerber Infinity Ultras? I love this light and EDC it, but constantly whacking it is annoying and I shouldn't have to do it at all. I could probably return it (again) and risk getting a much more blue LED, but I'd rather keep this one if all I have to do is pull the spring out a bit or something. Plus what guarantee do I have that this isn't a common flaw, and any new one I get will display the same issue?

Anyone with experience on this issue care to help?

Try cleaning the threads and adding a drop of conductive lube...
The bottom contact requires a Q-tip to clean.
I'm not sure where there is white stuff but if it can prevent contact in any way, then find a way to get rid of it.

[ QUOTE ]
The_virus said:
...Every now and then I'll twist it on and nothing will happen. Giving it a good whack turns it on, but never completely solves the problem, eventually I will experience this again and have to whack it again.

Anyone with experience on this issue care to help?

[/ QUOTE ]

It probably just has a dirty contact.

Get a pencil with a clean, live eraser. By live I mean not a pencil that is old enough that the rubber has became hard and dead.

I rub the flat head of the eraser on a small piece of 220 grit sandpaper so nice pink eraser is exposed. Then reach way down into the body of your light with the pencil and 'erase' the oxidation on the little spot where the cell hits the bottom of the tube.

If oxidation is the problem the eraser top will be black when you pull it out. If so, refresh the eraser with the sandpaper and repeat. Continue until the eraser comes out looking clean.

That will usually straighten it right out.

Also, rub the plus and minus contacts on the cell vigorously on a coarse cotton cloth (like denim) before re-assembly.

Thanks mates, I'll try cleaning it and see if this problem goes away. I did notice tiny black circles on the batery contact points that I just rubbed away with my finger...I'll just have to do the same on the contact springs inside!

The end of the spring at the back of the bulb may be a bit hard to clean, but I'll try it. I've been looking at pictures of the old CMG design and it looks like the old style had the - end at the back of the bulb against a flat contact point, now it's reversed to the + end behind the bulb, and both contacts are springs! Harder to clean for sure, but I think dirty contacts are the problem. I'll post again if the problem is solved, thanks again! /ubbthreads/images/graemlins/smile.gif

UPDATE: Yep, looks like the diagnosis was correct, the eraser came up black. Not really black though, the part that turned the eraser the blackest was the (-) end of the cell itself! I used the eraser on the battery to see if there was any oxidation on the cell and the - end was dirtier than anywhere else in the flashlight. I did get some off the (+) contact spring too, not as much as off the cell itself, but that was the second most dirty area.

The light should be free of any oxidation residue now, I'll update again if the problem persists. This problem was the annoying intermitent type that you could only experience "sometimes" and not often enough that you could reproduce it on demand (like say at the returns desk of a store!). Thanks again for the help, looks like this case is solved. /ubbthreads/images/graemlins/smile.gif

I've also had good results using the pencil eraser trick on 'sheet metal' spring contacts and coiled spring contacts. Try making contact and then spinning the pencil, among other movements.

I'm still having this problem, the eraser makes it better, but it seems like the problem comes back.

I think the spring at the back of the LED is covered in oxidation, and I can't quite get at it. Due to the small space for the pencil, I can only really make contact with the tip of the spring. I'll try compressing it harder to make contact with the lower coils.

I know there's still oxidation in there because the black ring on the (+) side of the battery is still there, even after I've rubbed it clean about three times.

I also read in another thread about how anodized threads on caps can break the current, or make it kind of flaky. I wonder if this is an issue with the Infinity Ultra. I still have yet to get some conductive lube as suggested, but I think I should try that too. There isn't a whole lot of lube on the threading, but you can tell it's there.

EDIT:
I also took a pair of tweezer surgical clamps and pulled the spring out just a bit, so the battery is definitely making good contact with both springs now.

Thanks for the further advice, keep posting if you have anything to add people!

I had a CMG Sonic that did the same thing. It would turn off randomly until I whacked it slightly. Finally no amount of whacking would turn the light back on. Got a replacement from Gerber.