BASIC FLASHLIGHT TROUBLESHOOTING GUIDE

Cataract

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I see too many threads about "my light won't come on" where people just do not know the basics of what to do in that type of situation, so here it is in a nutshell:

BASIC FLASHLIGHT TROUBLESHOOTING PROCEDURE:

1 – Check the battery polarity (most often positive towards the head, but not always)

2 - Make sure all parts are screwed in all the way and remove / reinstall your dropin if applicable while inspecting for broken parts.

3 - Try a new non-rechargeable battery (and new bulb if it’s an incandescent)

4 - Clean all contacts: inside the head, spring(s), tube ends and threads. (Rubbing alcohol and a Q-tip work fine or this)
4A - For twisties and lights that have erratic behavior: check if your o-rings are not creating too much friction (too dry or too big) or not enough tension (too small). Big o-rings can prevent contact, small o-rings can make contacts happen when not desired, causing flickers or undesired mode changes.

5 - Remove the tailcap and short the end of the battery with the end of the tube (a paper clip works just fine).
5A - If this works: tighten the tailcap retainer ring (note that some are reverse threaded).
5B - If tightening the retainer ring doesn't work dismantle the switch, clean all contacts inside the switch area
and reassemble.
5C - If this does not fix the problem, but the light comes on when you short the battery and the tube end, you most likely have a defective switch.

6 - Contact you dealer. If the dealer warranty is over, contact the manufacturer. Some dealers and manufacturers will honor the warranty for longer than stated or will provide replacement parts for a reasonable fee and sometimes even for free.

Don’t just give up on a light or brand just because your light didn’t come on.

As a standard maintenance procedure, you should lubricate your o-rings (see the comprehensive grease and lube thread for more details) and clean your contacts on a regular basis (at the very least once or twice a year up to once a month, depending on your usage.) Once a year, I check that my retainer rings are screwed in properly and I basically never have any problems.

Let me know if I forgot anything and I invite you to share your tips & trick or stories of a light that neede a simple maintenance to get going again :thumbsup:
 
Last edited:

Cataract

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Good point. I added a comment on dropins on the second line.

The goal here is to get newbs over 99% problems while not running the risk of voiding the warranty on new lights, so I prefer not to mention taking the pill out or anything like that. I'm hoping the mods will notice this thread and make it a sticky so people don't feel the need to start a thread every time a light won't turn on due to a small maintenance related problem. In-depth troubleshooting is rarely needed (virtually never if the light is under warranty) and very often requires more specific procedures like how to remove a specific pill and should also be accompanied by recommendations from someone who already opened that specific light when possible.
 

^Gurthang

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Cataract,

I get your point about taking apart a light & voiding the warranty. I was mainly thinking of P60 based lights when I responded the first time. I'll second the motion to make this a "sticky" thread for helping newbies, especially since I've gotten a small amount of grief for suggesting [to newbies] to use the search function to find the info they seek. Another suggesttion if this is made a sticky thread is to add some pics showing how to tighten a tailcap switch ring or a loose connection, or some sort of helpful pics.
 

jorn

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There is a sticky about stuff like this (with pictures) in the budget part of the forum.
 

Cataract

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Cataract,

I get your point about taking apart a light & voiding the warranty. I was mainly thinking of P60 based lights when I responded the first time. I'll second the motion to make this a "sticky" thread for helping newbies, especially since I've gotten a small amount of grief for suggesting [to newbies] to use the search function to find the info they seek. Another suggesttion if this is made a sticky thread is to add some pics showing how to tighten a tailcap switch ring or a loose connection, or some sort of helpful pics.

Excellent points there. I'll make the commitment to add pics with arrows to the areas to clean, disassembled switch and whatever seems useful if the mods decide to sticky this thread.



There is a sticky about stuff like this (with pictures) in the budget part of the forum.

Didn't know about that one, but it does concentrate more on the internals rather than the regular maintenance points. Nice pics, though.
 

russde

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Cataract,
As a newb I want to thank you for taking the time to put this together. I knew about most of these, others I would have spent a great deal of time either searching (here) for or fumbling around until I thought of it myself.
Cheers!
 

Cataract

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Cataract,
As a newb I want to thank you for taking the time to put this together. I knew about most of these, others I would have spent a great deal of time either searching (here) for or fumbling around until I thought of it myself.
Cheers!

Thanks, took me a while too at first and that's why I figured these little things needed to be put together ;)
 

sold365.com

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Thanks, as a relative newbie to Flashlight repairs, following your steps helped me start up a 10 minute RUN BC 10!
 

tam17

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Thanks for starting this thread, Cataract! A little contribution from my fresh experience.

Twisty flashlight changes modes out of sequence + very hard to turn on and off

I've almost returned a perfectly good LD01 (XP-G R4) today. At first it seemed like it's changing modes randomly (as you probably know, LD01 is a twisty with med>low>high sequence), and that p*ssed me off so bad that I've failed to notice how dry the O-ring was, making turning on and off very hard. Upon arriving home, I've removed the O-ring and then tested the UI: it worked flawlessly! I've lightly polished the sealing surfaces with used "1500" waterproof carbide paper, washed the O-ring in dishwashing detergent, cleaned everything, applied silicone grease and re-assembled. Everything A-OK!

So, dry and sticky O-ring can affect the overall flashlight operation, not only the waterproofing.

Cheers
 

Sub_Umbra

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I've got a problem with #4.

Alcohol isn't the best thing to clean contacts, though it may work if nothing else is available. The catch is that you have to use the 91% alchol and not the far more common 70%.

It doesn't make any sense to try to clean electrical contacts with anything that is 30% water.
 

Irelander

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I've got a problem with #4.

Alcohol isn't the best thing to clean contacts, though it may work if nothing else is available. The catch is that you have to use the 91% alchol and not the far more common 70%.

It doesn't make any sense to try to clean electrical contacts with anything that is 30% water.

I highly recommend DeoxIT. I work with electronics all day and much of it is repair work. We have tried all types of contact cleaners and DeoxIT works wonders and keeps the contacts looking good for a long time. Grab a bottle and it will last you a long time if all you are doing is cleaning your light contacts once in a while. I just cleaned my Quark 123 contacts with it the other day and they look as good as new now.
 

tam17

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I've got a problem with #4.

Alcohol isn't the best thing to clean contacts, though it may work if nothing else is available. The catch is that you have to use the 91% alchol and not the far more common 70%.

It doesn't make any sense to try to clean electrical contacts with anything that is 30% water.

Alcohol is recommended in Fenixlight Ltd.'s user manuals. Quote: "Clean the contact points with an alcohol soaked cotton swab." (Source: LD01 R4 User Manual). Which alcohol and which concentration - not mentioned.

I'm using either 95% ethanol or "Oszillin T6" contact spray for fine electronics. Never use water-based products or WD-40...

Cheers
 

Cataract

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I just came back from vacation to see my thread has attracted some new comments.


Thanks for starting this thread, Cataract! A little contribution from my fresh experience.

Twisty flashlight changes modes out of sequence + very hard to turn on and off

I've almost returned a perfectly good LD01 (XP-G R4) today. At first it seemed like it's changing modes randomly (as you probably know, LD01 is a twisty with med>low>high sequence), and that p*ssed me off so bad that I've failed to notice how dry the O-ring was, making turning on and off very hard. Upon arriving home, I've removed the O-ring and then tested the UI: it worked flawlessly! I've lightly polished the sealing surfaces with used "1500" waterproof carbide paper, washed the O-ring in dishwashing detergent, cleaned everything, applied silicone grease and re-assembled. Everything A-OK!

So, dry and sticky O-ring can affect the overall flashlight operation, not only the waterproofing.

Cheers

Thanks for your contribution, I'll add something about checking o-rings.

I've got a problem with #4.

Alcohol isn't the best thing to clean contacts, though it may work if nothing else is available. The catch is that you have to use the 91% alchol and not the far more common 70%.

It doesn't make any sense to try to clean electrical contacts with anything that is 30% water.

Believe it or not, this is a very common practice in electronics to use alcohol, wheter it be 90% or 70% alcohol (most do prefer 90 - 95%, though). First off, board contacts are normally of a type that is very hard to corrode, if at all, and board traces are protected by a coating. Second, the evaporation rate of alcohol (including 70%) is high enough that nothing is left on the surface within seconds. In general, there is only a very small deposit of dirt, oil or oxydation on flashlight contacts and even a dry q-tip might do the job, but sometimes more is needed and alcohol is used because of the high evaporation rate and also because it works well on most oils.

Contact cleaner solutions are also recommendable, but there is no evidence whatsoever that using 70% alcohol will do anything bad. Plus, most flashlights have gold plated contacts and gold has pretty much 0 tendency to corrode. Whatever you use to clean your contacts, just make sure you don't use so much it can leak inside the head or the tailcap. What you really want to avoid is humidity inside the head with the electronics, that's where water can affect the durability of the electronics, but exactly how much so is very open for debate and has more to do with the soldering quality than anything else. Also, know that most contact cleaning products do contain some water and that some of these products are aggressive enough that they can cause premature wear on contacts or dissolve gold plating when used frequently. Basically, the more a product cleans oily stuff easily, the more it is likely to remove gold plating, but that is only a concern if you clean your contacts often.

I highly recommend DeoxIT. I work with electronics all day and much of it is repair work. We have tried all types of contact cleaners and DeoxIT works wonders and keeps the contacts looking good for a long time. Grab a bottle and it will last you a long time if all you are doing is cleaning your light contacts once in a while. I just cleaned my Quark 123 contacts with it the other day and they look as good as new now.

Deoxit will remove the worst of residues, even some rust caused by a leaking battery. I still try to use it with caution but, yea, it makes contacts look great. It is also designed with gold plated contacts in mind, so is very recommendable.


Alcohol is recommended in Fenixlight Ltd.'s user manuals. Quote: "Clean the contact points with an alcohol soaked cotton swab." (Source: LD01 R4 User Manual). Which alcohol and which concentration - not mentioned.

I'm using either 95% ethanol or "Oszillin T6" contact spray for fine electronics. Never use water-based products or WD-40...

Cheers


Most (if not all) manufacturers of anything electronic will recommend using alcohol for cleaning contacts and, no, no one will specify which concentration: 70% and up is good enough for most uses. Just don't overdo it whatever you use.


NOW FOR THE RESERVE SIDE OF THE COIN:

I definitely recommend NOT using alcohol on your o-rings as it can dry and cause cracking on certain materials. I usually remove my o-rings before doing any cleaning on the threads.
 
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