Fenix LD01 twisty troubleshooting

Hi all, looking for some advice. i have an older Fenix LD01 that all of a sudden stopped working on me. won't turn on when tightened down. i took the tail spring out and added copper braid to see if that helped. still didn't work. removed the bezel and put leads to the pads. LED lights up fine. i put leads to the underside of the driver and nothing. when i shake the light hard, it turns on and off. Driver issue?

Edit: Light has been fixed! see post #9

It would certainly seem so. Ain’t got that particular light, so can’t say for sure.

Maybe try to buff all contacts points, including the end of the battery tube, retaining-ring (if any), center pad, etc.

If it’s got a RR, loosen it or remove it even better, buff it (and both sets of threads as much as possible), snug it down hard.

A Q-Tip dipped in alcohol after buffing will both remove grit and also clean things as a solvent.

Beyond that, btfoom.

Thanks, i’ll try cleaning the contacts. that’s all i can really do i guess as removing the driver looks impossible. looks to be glued in place with no holes for a tool to thread out. No access from the top either as it’s just two hole for the wires. What a pain. its been a good light.

Wellp, here’s the thing… “It’s been a good light” sounds like you’re gonna toss it. Don’t.

If the LED works, then it’s likely that replacing the driver could/would fix the light. So if it’s a 17mm driver (or whatever size), you could even drill out the old driver and replace it with a new driver in the right size. Lotta drivers have vias around the outside that’re filled with solder that you could press-fit the driver into the hole. And if not, people’ve soldered thin wire strands ’til it is press-fit.

So get even a cheap 1-mode or 3-mode or whatever driver, and you can get it working pretty easily.

No one says it has to be a direct-drive driver that could fry the LED in seconds. Start modestly, tweak later. For a long time, my EDC was a 1-mode 1.4A ’502, simple on/off when I needed it, reliableAF, nothing to break. Did like 98% of what I wanted it for.

Just goggled it now, and it’s a teeny little thing, an AAA light.

Wellp, Convoy, Sofirn, etc., might have drivers for their AAA lights. Probably also press-fit.

Anyhoo, I’ll defer to others who may’ve done similar.

The center positive contact on the head in your picture looks dimpled, has it been crushed by overtightening the battery? If so a dab of solder to raise the contact up might help.

its looks fairly flat close up. Also when i tried the center and outer ring with leads it didn’t light up. i think something is loose and it makes contact when i shake the light.

Mine’s still kickinm (2013), but I recently replaced her. :smiley:

Decided to open up the head again to see if I could fix it. I didn’t want to give up on it. every time I shook the light it turned and off randomly and I could hear something loose. I don’t know what it’s called but it is the biggest component on the battery driver side. it had coils around it. this piece was loose and lifting off the board. I wedged a thin piece of heat shrink between the top of it and the upper driver board too keep it from moving. I applied power to the contacts where the battery would be and it worked! Probably not a good idea but I injected some regular hot glue in there to make it stay as I don’t own any potting compound. Everything is back together and works as it should.

Solder instead of hot glue would have been better. :wink:

That part is the inductor. Typically the heaviest part on a driver board for a single cell. They are notorious for breaking free after a number of drops. That’s exactly why potting increases reliability.
Excellent job on the repair!