# LED Troubleshooting guide (budget lights)



## nakamoomin

I’ve just been introduced to the world of LED lighting. Over the last two weeks I’ve received two lights from an undisclosed (but very popular) dealer in HongKong (DX).

These so-called budget lights are great value, but both have been “twitchy”. The first (Romisen RC-F4) had an issue with its switch being unreliable. The second (MTE “P7-D”, 5-mode) had a flickering issue. I’m sure others have problems with budget lights, and therefore I’ve made this tiny troubleshooting guide. Feel free to comment as I am a noob with regards to LED flashlights (except for a Luxeon I bikelight I designed and built for an engineering project in university a few years back).


*OK! Here goes!*






_my lights_

These are the lights I will use today (I also have a DX Pig-light, but I’ve never had any issues with it, so recon these are maintenance-free, ha ha), the Romisen RC-F4 and the MTE “P7-D” (5-mode).



*DIM OUTPUT*


_*1) Check the batteries!*_
If output is dim, but there is no flickering issue, the battery is a likely culprit. Some voltage-regulating circuitry may also flicker when the voltage drops, but this is rare. Remember: If your light uses more than one battery you need to be EXTREMELY careful not to mix-and-match batteries of different capacity or voltage. If you suspect that one of the batteries are dead (sometimes even brand new ones are dead) remove them and get them checked. This goes for all lithium-based batteries, primaries as well as rechargeables. Consider purchasing protected cells as well. 


_*2) Check the LED*_




Visually inspect the LED to see if it shows any sign of being “burnt” (discoloration, dark spots). This should be visible through the lens.


_*3) Check the solder-points and contact-points*_




Visually inspect the solder-points by removing the head. If this is not possible remove the bezel and extract the glass and reflector if possible. Some heads are glued (such as the MTE “P7-D”) but it may still be possible to access the LED/pill by removing the bezel/lens/reflector. Be very carful not to touch the reflector. It is polished and aluminium is soft. If you don't know what you're doing cleaning it is likely to ruin it! Wipe the lens when you reassemble. If everything seems all right, continue troubleshooting using the steps regarding flickering/switch issues.



*FLICKERING / SWITCH ISSUES*


_*1) Clean the internals of the light*_
Use compressed air or “tap and blow” to make sure no metal shavings/debris from the manufacture of the metal parts is caught inside the tube. 


_*2) Check the contact between body and tailcap/switch-assembly*_




Remove the tailcap and use a paper-clip or otherwise suitable piece of metal and make contact between battery negative and the body. Make sure you make the contact on a part of the body that is not anodized. If the flickering stops, this may indicate a “bad” switch or bad contact between tailcap and body. Use a pair of needle-nose pliers (or a pair of sturdy tweezers) to tighten the switch-assembly (turn clockwise). If the switch-assembly is tight in the tailcap, remove it (counter-clocwise) to inspect.




Some switches are “open” (MTE “P7-D”) while others are “closed” (Romisen RC-F4). If your switch is of the “closed” type, it will hold the switch within a container that is inserted into the tailcap. If it is “open” the tailcap itself will form the container.




For “closed” switches, tighten the inner seal (see picture), reassemble and test. If no improvement is seen, continue with procedure for “open” switches.
For “open” switches, remove the parts and check for contact. Use a fine-grain sanding-paper (400 grit or higher) to clean the contact surfaces for solder-flux and other impurities. 




Reassemble.


_*3) Check the contact between body and pill.*_
Do the paper-clip test as described previously. Vary the pressure on the battery. If the flickering is reduced/stops when pressure is applied, this indicates a contact problem between the pill and the body.
Get access to the pill by removing the head or by removing the bezel/lens/reflector. Remember to NOT touch the "shiny" parts of the reflector with your bare hands (or anything greasy)




Check if the pill is tight by using a pair of tweezers/needle-nose pliers and twist it clockwise. If it is tight there may be a problem with the wiring, which requires advanced repair (perhaps to be covered in another thread). 
Reassemble and you're done.






I hope this is helpful. I searched these forums for help on my MTE “P7-D” as it was nearly unusable when I got it (heavy flickering) and there was no easy check-list for troubleshooting these lights. Here it is! Feel free to comment!

Tom.


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## Oddjob

Welcome! Great step by step pictures and instructions! You should do this with the more popular lights (although I suppose they would be similar to the ones you used).


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## Flying Turtle

Great first post, nakamoomin! Welcome to CPF. Looks like you should be happy here, and we appreciate your input. Your guide is excellent.

Geoff


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## yellow

wow, great.

As if You were an old-timer (on cpf)


covers really everything


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## nakamoomin

Thanks for the feedback, guys!

I guess most lights are built (more or less) the same, so I thought it'd be nice to go through some basic troubleshooting. I know others are strugling with the build-quality of these cheap lights. Usually it all comes down to bad assembly (thankfully). 


Right now I am contemplating a direct-drive mod for the RC-F4 (a la BessieBenny) which will include pics (of course).

Also I'm waiting for an SSC P4 U-bin on star to upgrade my ancient Myo-XP.
Tutorial with pics will follow. 

Again, thanks for the feedback, keep it coming..


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## Gunner12

Wow! Nice first post!

I think this should be stickied, to cut down on the "my light is broken, how do I fix it" type posts.

:welcome:


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## tnforever

We should sticky this and add to this as more useful things come along. This is a great beginning post, but far from extensive. With a few more additions this could be fantastic!


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## ANDREAS FERRARI

WOW! Are you really new here?This is some fine work.Gunner12 is right-this should be a Sticky.:welcome:


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## Patriot

Yes this is a handy thread and covers the basics very well.

Great first post and welcome to CPF!

:welcome:


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## nakamoomin

Thanks for all the positive feedback, guys! I really feel welcome!
I've been reading the forums for a month or so, especially bessiebenny's budget guide but this is my first post.

As for additions: Bring it on! I am more than willing to add to this post. 

I am also contemplating an "advanced troubleshooting" or "troubleshooting for power-users" which would include: resoldering bad connections, application of thermal paste/glue, LED replacement, meassuring power draw and voltages etc.
Maybe even some modification (conversion to direct drive).

Again, cheers guys, and keep suggestions coming. (I'll add them as soon as i have a chance)

T.


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## horizonseeker

Great thread. A lot of this stuff I figured out by lurking and just doing it, but it would be a lot easier to have a pictorial like this one for beginners.


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## Oddjob

Maybe this should be a Sticky.


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## NOT THE SLOWEST

You are my hero. I finally know what part of my light doesn't work, the switch. Now I need to find a replacement part.

Thanks

Robert


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## lrp

Awesome and welcome!!


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## ninjaboigt

very very nice


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## NOT THE SLOWEST

Got the switch, my light works. I'm a happy Camper. I cycle through the street of NYC and have found the strobe mode the BEST way for me to be noticed. Yes it may be overkill, but better than road kill. It's the only thing I have found that "may" get me noticed on my nite commute. Now I'm off to find an affordable light that I can use. P7's look nice, but need longer battery run time. 

Rob


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## DM51

Moved to the Budget Lights section; now a sticky there.


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## setherd

*problem with P60 drop in.... intermittent contact????*

A while back I bought a cheap Dealextreme LED dropin for my surefire Z2. I often have to hit the end for it to work. even after I screw the tailcap down fully it wont come on. But other times it will go days without issue.
I don't think it a tailcap issue. I guess the body of the dropin isn't completing the circuit in the head.

does this make sense? it was a cheap one. I want to get something better but can't make up my mind.
I have a mcclicky switch on the way so I can confirm if its the switch or not.

Is there something I can put on the dropin to help contact? maybe some arctic silver?

thanks!


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## dottormale

fantastic post ! 

thank you , i fixed my new aurora p7 , that wasn't assembled properly .

thank you form italy )))))))))


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## mgm1

fantastic post ! 


thank you form Russia!


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## drizler

Don't forget to use some of this stuff when you think there is a conductive issue.      I got this stuff at Advance Auto although any other auto parts place should have it possibly even the bigger Walmarts.     I have come to love this dielectric grease and wish I had found it 35 years ago.    I now use it on all outdoor bulbs and electrical connections to insure no weather related problems later on.    It's also great under auto sensor leads to block corrosion and its troubles.    As for flashlights I had gathered a collection of 6 of those $2 LED lights you find at the counter at Advance.   Given 6 months to a year none of them worked at all which is no surprise.    I greased every cheap metal contact piece  with it and viola, every one now works.   This stuff is better than grease as it won't short out the connection like regular grease will.    A tube of this should last at least 10 years and keep your electronic goodies very happy.:thumbsup:a


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## ddac

Awesome tutorial!!

I have the same MTE light. I purchased it as a dedicated bike light (strobe mode). However, after a few weeks of use, the light started flickering. It would go dim and be bright again. 

I'm going to try the paper clip test.


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## ddac

I did the paperclip test and it was day and night. With the  paperclip, it did not flickering and there was no dimming!!!

I examined  the tailcap. It was very tight. I loosed it with needle nose pliers and  couldn't see anything wrong. I used fine grit sandpaper to sand  everything down and cleaned it with alcohol before putting it back  together.

Result: Still flickering. It also goes dim & bright  erratically when i start vibrating the light (imitating the environment  when it's mounted on my handlebar).

Any ideas?


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## row

Thank you very much for the detailed post


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## hank

Aside -- can you tell if it's a real or fake MTE?  From somewhere else, I found "an authentic MTE, you can tell because the PCB is encapsulated and epoxied to the recess in the brass module with thermal epoxy for better heat conduction, not exposed like all the fake ..."


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## Jaysonr6

Hi.

I know i have found it somewhere in my travels...

But does someone have a list of the o-rings needed to replace all of them in the dealextreme SSC P7?

I was hoping to go get some better quality ones and use a decent lube lik[FONT=arial, sans-serif]*e *​molykote.[/FONT]


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## Jaysonr6

anyone at all?

I am goin to Thailand in a week and would really love to replace the o'rings and test this out.


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## AnAppleSnail

Jaysonr6 said:


> anyone at all?
> 
> I am goin to Thailand in a week and would really love to replace the o'rings and test this out.


The 'Dealextreme SSC P7' is not a single light.  The SSC P7 describes an LED used in a few dozen lights.  A good guess is:

1" Bezel O-ring
Same-size as solarforce/P60 style lights for head and tailcap O-rings


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## aosinator

Thanks so much for posting this guide.  I had 2 flashlights which have been flickering wildly, especially when gently shaken.  This guide helped me figure out why, and then to fix it.  :twothumbs


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## DP Hunter

Great guide - thanks for posting it! I may be able to start doing this!


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## hantulaut

ah this one ive been looking for. My cheap china flasglight has sudden flickering dozen times when it switch ON.
Wonderful pics info too. Thanks


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## jarma

excellent!! fixed my flicker problem in minuits, brilliant to fix what im sure is a very common problem on budget flashlights,


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## JaffoAZ

This is hilarious. This stickied post is more than a couple years old. I Have a Solarforce 2011 version L2 that I have been in love with since I got it a couple days ago, and it has performed flawlessly with some generic XM-L T6 drop-in that came with my first budget performer, an Ultrafire 502b. I really thought I'd struck gold with less than $30 investment for such a nice quality host (and that 502b) and a cheap drop-in. 30 minutes ago I was severely peeved when suddenly the torch became a tactical pressure switch-only light, irritatingly cycling through the 3 brightness modes and 2 worthless blinky modes with just half pressure on the switch. The light would just turn off completely if I fully click the switch. Not only that, but if I smacked the setup in my hand sharply, it would once again cycle through modes. UGH!!! I was thinking "Oh crap - I've just discovered the downfall of budget Chinese torches." Then, I reverted to one of the top three static posts on this budget light forum, and by step 2 or 3, my torch was back to being awesome again. Tightened the containment washer in my switch and all is fine again. Thanks a million, nakamoomin. Where would us clueless newbs be without ya? Probably posting really ignorant negative reviews on Amazon.com or saturating the forum with countless redundant "what the hell happened to my stupid flashlight?" posts or something... God, I love this stuff. 03:naughty:-30-2009, 06:12 AM


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## aba1

Hello,

I've noticed that my flashlight luminosity depends on the outside temperature
Do you think led performance depends on the environment?
Thank you in advance


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## Bevis

nice guide. i have a pair of it and they are working fine. i dont want to do changes as its sensitive to do this stuff. well you explained well but i am little scary.


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## sikreto

Good thing i found this, I was about to throw my flashlight.  As I have followed step number 2 step by step as I've already determined that it is a problem in the switch, and even followed some of the extra taken by other members here, my flashlight still doesn't work. What other considerations have I missed?


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## Kappycpf

Thanks for the explanation. Don't forget to note that one must remove the rubber like cap to access the switch in the tailcap.


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## andymac

joined candlepower and found the answer to my nightsearcher tracker problem within 5 minutes many thanks :thumbsup:


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## TheIrishExit

This post helped me trouble shoot my Solarforce L2P, or at least narrow the problem down to the drop in. Thanks.


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## mosquito

For reference:

If you need to remove the switch from the end cap of a small Nebo -- like CSI Edge, US Army TAC-50, and probably the CSI LUMA50 and Lumiere -- then:

1) Remove the end cap from the body.
2) Remove the rubber seal over the end of the switch. (Pinch it out with thumb and forefinger.)
3) Press the switch assembly out with something like a #1 or #0 flathead screwdriver. (The switch assembly is not screwed in.)

--

So far, I've had three of these lights and I agree that they're not very reliable.  So, I always keep a spare with me.  When they start flickering or being inconsistent, usually wiping the AA cell contacts improves it enough for the night.  If that's happening too often cleaning them well makes them bright and reliable again.  

For me the pros are:

- Cheap
- Durable 
- Baseball cap-mountable 

Cheap?  $10.  For durable, I've been using these lights for about two years on a weekly+ basis and haven't broken one yet.  They get dropped and mashed, not infrequently, and are always bouncing around at the bottom of my messenger bag.  For my particular purpose of having a small, convenient head-mounted light they're great because they clip onto the band of my baseball cap as I'm working and stay put.  Always keeping a spare isn't a bad thing for me either because I often have other people -- musicians, producers, performers -- ask to borrow my light.  With two I can loan one and keep the one I'm using where I need it.


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## TxRobtrx

THis is a great sticky - thanks for putting it together


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## Talbingo

Thanks for post this is great info and I'm sure it will come in handy at some stage.


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## Hoggy

I'd just like to add my own testimonial to this aging sticky..... Which, BTW, this forum started my flashaholic ventures because I wanted to find out why my batteries became 'dead' in a 4-AA camera shortly after charging. I ended up buying the MAHA-C9000 and LaCrosse chargers - and even started labeling and tracking my batteries in a spreadsheet due to this forum.. _UNTIL_ I discovered Eneloop batteries, that is! Now I don't bother - and will never buy anything other than Eneloops. ... Then I ventured into ecigs and got involved with Li-ion batts. This forum has, and continues to be, an invaluable source for all things battery! Plus, I'm up throughout the night - hence my flashaholism. 


I had bought a slew of AA & AAA _sized_ lights from DealExtreme around 2009 or so. *ALL* but *one* had issues.. The standard flickering, needing to hit the head in my hand, tighten and/or loosen the tail and/or head, etc. ... The _good_ one being an UltraFire A6 Stainless Steel AAA-size.

Fast-forward to now, 2016, and I wanted to get a second UltraFire A6 SS. It was hard to find, but I did find one on another site, and ordered it.. THEN I had discovered that LED tech has advanced since ~2009, so I was able to cancel that order. (Don't get me wrong - it *is* a wonderful, beautiful, and powerful flashlight - even more powerful than most of the _AA-sized_ lights I had bought (using just Eneloops) - but it _is_ slippery and heavy.)

So I decided to order another slew of powerful flashlights from DealExtreme, only AAA-size this time, hoping to get _at least one_ more that didn't have issues...
Out of the 2 that have arrived so far, _one_ didn't have any issues from the get-go - a SingFire SF-364, another beautiful and very powerful flashlight. I was prepared to send the quirky one back, but..

*THEN* I found this thread and did most of it to ALL my flashlights that had issues, old and new alike - using both contact cleaner with Q-tips as well as compressed air.
And now...

ALL OF THEM, old and new alike, are *fully functional!!!!* Without any 'quirks' whatsoever! ..And most are even brighter, I might add, after also cleaning the lenses and reflectors! *:twothumbs

* (Well, save for one, in which I broke one of the tiny wires that were soldered to the PCB.. But I knew I was pushing it, so it was my fault. So maybe one day, I'll try out my lack-of-soldering-skill and see if I can fix it.  )


Ehh... There's just no way I'm going to be spending, even over $20, for a single light. For their prices, I'm willing to wait a couple/few weeks - and even do cleanup on their shoddy workmanship. Besides, it also gives me something to tinker with.


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## MrFastCarsFun

Hoggy said:


> *THEN* I found this thread and did most of it to ALL my flashlights that had issues, old and new alike - using both contact cleaner with Q-tips as well as compressed air.
> And now...
> 
> ALL OF THEM, old and new alike, are *fully functional!!!!* [...]


That's awesome! Funny what a little preventive maintenance can do. I always wondered if tinned wiring makes better long term metal conduction.


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