L2T output drop in low mode -- thoughts?

Hi! My L2T has developed a worrisome problem. The light output on "low" has suddenly dropped by at least half. Output on "high" seems normal. It's not a battery issue. No flickering or corrosion noticeable. Any thoughts?

walkabout said:

Hi! My L2T has developed a worrisome problem. The light output on "low" has suddenly dropped by at least half. Output on "high" seems normal. It's not a battery issue. No flickering or corrosion noticeable. Any thoughts?

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Send it back?

clean the threads ?

NA8 said:

clean the threads ?

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Second that. Inside and out. If you've have grease on the threads, remove it. Some lights can tolerate a little grease there but a lot of grease is not a good idea on this type of system. On low, the current runs through the threads.

Thanks for the replies.

I must confess that I don't see how cleaning the threads would make a difference. (The threads were greased lightly at the factory; I haven't added to that.) If it works normally in "high" mode, there must already be a proper current path.

The "low" mode problem must surely lie in the microprocessor/voltage regulator. Or am I out to lunch?

Anyway, I sent an e-mail to the supplier. They are forwarding the e-mail to the manufacturer. I smell potential "buck-passing" but I'll keep an open mind as things progress.

Meanwhile, I think I will clip a Photon on my keychain in case this light conks out on me.

walkabout said:

Thanks for the replies.

I must confess that I don't see how cleaning the threads would make a difference. (The threads were greased lightly at the factory; I haven't added to that.) If it works normally in "high" mode, there must already be a proper current path.

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No, that's only for high. There are two separate current paths in this light. When in high mode, the neg path uses the rim of the barrel against the outer edge of the driver board when you 'tighten' the head down. When you 'loosen' the head for low, you break that circuit and the neg current path is made through the threads. That change of path to the board is what puts it into the low mode. There must be good contact in the threads for the light to work properly. (on low) If the machining is just right, or actually, just wrong, you may loose slight contact and low mode may become intermittent.

Clean the threads, inside and out, with some alcohol and test her again. Hopefully that do the trick. :thumbsup:

Hey, you learn something new every day! I did not know this light used two current paths.

Even though the threads looked shiny and new, I gave them a good cleaning and voila, low mode started brightening up.

Why it decided to act up after working perfectly for six months is, I suppose, one of those random mysteries.

At least I can trust this light again (hooray!).

Thanks everyone for the wise advice.