LD01 Troubleshooting

Hi folks,

I've got an LD01 that I've had for about a year and am having really strange problems with it. I'm hoping some of the more experienced folks here might be able to help me get the gremlins out or at least help me explain the problem better to the dealer I bought the light from.

Basically the light will not turn on even if I have it twisted on. Sometimes it will not light at all, other times it will light weakly (like 1 lumen -- finally, an original LD01 with a low low! ). This problem develops if I EDC the light for a day or so.


I thought this could be the contacts, so from searching the threads, I've cleaned all of the contacts in the head, threads, and the end of the tube with alcohol and rubbed the spring with an eraser. I also thought this could be the battery and have found it reproduces regardless of what battery I've had sitting in the battery.

I've sent it into 4Sevens two times now and each time they haven't been able to replicate the issue and have sent it back, but it's always returned within a day or two of EDC.

I've created a video of the problem as this is probably the best way to show it: http://www.youtube.com/watch?v=ZDdE0538RcY


Short of asking 4Sevens to EDC the light themselves, I'm at a loss as to the next steps. Any ideas o' kind CPF souls? :shrug:

Try De-Oxit Pro contact cleaner, also sold by 4x7. Also check if the problem is thermal, e.g. warm the light up with your hands. It could be a micro-crack on an internal trace in the electronics.

Could be a weak tail cap spring and a snug fitting battery.

:welcome:

You did everything you could. I think paulr has it though. Smacking it to make the connection sounds like a cracked trace or solder joint.

The good news is there are a lot of excellent AA/AAA keychain lights out there to choose from now(cheaper too). :thumbsup:

paulr said:

Try De-Oxit Pro contact cleaner, also sold by 4x7. Also check if the problem is thermal, e.g. warm the light up with your hands. It could be a micro-crack on an internal trace in the electronics.

Click to expand...

Hi Paul,

I'll definitely give both suggestions a shot. I'm wondering if I should test both warming and cooling? The light spends most of its time in my pocket so it stays fairly warm.

If the issue is potentially a cracked trace or spring, is there anything I can do to get this to reproduce consistently? The 4Sevens folks have been nice to me both times, but their main issue is they want it to reproduce consistently before doing a warranty fix for it.

I'm wondering if maybe I should ask them to carry the light around for a few days. :sigh:

leonardc9 said:

I'm wondering if maybe I should ask them to carry the light around for a few days. :sigh:

Click to expand...

How about if you give it a thorough test after having it in the fridge for a while, or a warm car for the other temperature extreme? This might be a way to ensure that another person evaluating it could reproduce the conditions?? :shrug:

Kestrel said:

How about if you give it a thorough test after having it in the fridge for a while, or a warm car for the other temperature extreme? This might be a way to ensure that another person evaluating it could reproduce the conditions?? :shrug:

Click to expand...

I tried testing with both and unfortunately no joy. I'm going to send this back to 4sevens once again, but I'll try to talk to them on the phone first and see if they'll EDC it to get the problem to replicate rather than just doing a quick bench test and sending it back.