Hey Chloe, yea I got it from ebay so it’s unlikely they will exchange it. I will check the listing though and see what the terms were, perhaps email the seller. Was from HK I think, or maybe even mainland CH.
Normally, first thing I check are batteries. (you seem to have done that)
Then tailcap. Instead of using the tailcap, use a wire from the battery to the body. (you can just change tailcaps, high chance the answer lies there)
Check contact between driver/head/springs to body. (you can just change bodies)
Check wires to leds, any loose wires? Could the wire be shorting on reflector or something? (one some lights, that would require to take the driver out)
Investigate driver/do a driver swap.
Hey,
Is that a joke? It’s still connecting as there is still some brightness… could a less springy spring actually make it dimmer? I will check it if you think so.
“Normally, first thing I check
Normally, first thing I check are batteries. (you seem to have done that)
Then tailcap. Instead of using the tailcap, use a wire from the battery to the body. (you can just change tailcaps, high chance the answer lies there)
Check contact between driver/head/springs to body. (you can just change bodies)
Check wires to leds, any loose wires? Could the wire be shorting on reflector or something? (one some lights, that would require to take the driver out)
Investigate driver/do a driver swap.”
Hey,
Thanks for that. You’re right, good to start with process like that. I checked the brass/copper end caps and cleaned the one in the led end as it was a little discoloured (only slightly) no difference. Fortunately I have another model exactly the same so I will just swap the head assemble onto the body/tail assembly and see what happens. Easy as.
[5mins Later]
No, I swapped the head assembly to the tail end of the one that is working brighter and it was still noticeably dimmer, so it must be something within the led end assembly that’s making it dimmer 
It is really strange - there is light, but just not as bright. So annoying. Taking apart the head assembly doesn’t seem to be all that simple as it is built quite robustly. I will need a soldering iron too for re-assembly? Can’t even find a youtube video with a how-to and unsure of which search terms to use in the forum here… so many posts and models.
The spring at the driver(head) end are known to go bad on all the TRJ lights due to the high current.The springs overheat and loose tension and gain resistance.If it is not this then poss. a driver issue.Good luck!
“The spring at the driver(head) end are known to go bad on all the TRJ lights due to the high current.The springs overheat and loose tension and gain resistance.If it is not this then poss. a driver issue.Good luck!”
Wow! Very interesting. Thanks for the well wishes. Ok, I will have a shot at the spring as part of the process… can I just stretch it out again or do I need to get a new spring. Sounds bizarre but anyway. Still feels springy - infact I just checked it compared to the other one and they feel exactly the same insofar as springyness is concerned. More I eliminate the more I am coming back to Chloe’s comment re driver board.
I haven’t had the spring problem with my TRJ12, but I have read of it here before.I would guess that you would be able to tell if it is bad.If it is the same as your good light than that is probably not it.It probably is something wrong with the driver….keep checking your post though, I am sure someone with more knowledge will be by soon to help!-Rick
“I haven’t had the spring problem with my TRJ12, but I have read of it here before.I would guess that you would be able to tell if it is bad.If it is the same as your good light than that is probably not it.It probably is something wrong with the driver….keep checking your post though, I am sure someone with more knowledge will be by soon to help!-Rick”
Thanks Rick,
Yea, I just tried to take the board out but it’s obviously soldered on to some wiring inside and I don’t want to pull too hard or I’ll break it. Just need to figure out how to get it out then I can check for loose connections etc. Hopefully just change the board.
Regards,
James
BUMP - any help?
Can you swap the spring easily? Or even get a new spring, one that is better quality (not sure where from though).
Another idea is to use some braided copper wire:
Haven’t read the entire thread, but have you checked the spring in the tailcap? You’ll need tweezers to remove the inside of the tailcap.
Edit - o.k, now I have read the thread properly, so it’s not the tailcap spring.
I had a very similar problem with my ultrafire C8, it went dim and checking it on a multi-meter there was very little current. I ended up replacing the driver thinking it was a driver issue, however it was actually the LED that had gone bad.
If I understand it right, the J18 has a single positive and negative wire from the driver connected to the LEDs, the LEDs are wired together and complete a circuit/loop. If one of those LEDs go bad, then the circuit won’t complete or barely complete, causing the entire flashlight to go dim.
Problem is I don’t know an easy way to determine this. Looking at my LED and starboard it gave no clues that it was bad, solder points were good, however it was sitting loose in the pill so had poor thermal transfer.
One thing that should be easy to check is to remove the reflector and check the LED and LED starboards are firmly seated and don’t move around, if one is sitting loose then that could be the problem. If it is an LED problem and they all look fine, then perhaps someone with better knowledge may be able to suggest how to isolate the problem LED.
You could try turning it on and carefully checking each emitter to see if any seem to be performing differently, presuming you don’t blind your self, however considering the entire circuit would be effected it may be impossible to tell.
Of course it may just be a driver issue, however considering the odds, 1 driver vs 7 emitters……………
Hey Chloe,
I have a spare flashlight exactly the same model that works fine. When I put the entire tail assembly of that one on to the head of the one that is dim it is still dim… so I don’t think it’s a tailcap problem. It could potentially be the spring in the head plunger under the retaining cap but I don’t think so. All it has to do is make the connection, which it does, and as this torch was working brightly not too long ago I am assuming it is a circuit problem somewhere i the head, driver or as mentioned below/above a problem led.
Thanks for you post whokilledJR,
I have tried to remove the reflector but it is apparently secured by two screws accessed from below and seeing as I am unable to remove the driver board I can’t get to them. To be honest I have no idea how they put the driver board in there. I have fiddled with it for about 30 mins trying to get it to come out but no matter which angle I try it just doesn’t want to fit through.
UPDATE* My email to Trustfire.com was met with a disassociation and claim of indemnity from the manufacturer. They will be of no help unless you purchased it directly from them. So much for standing behind your product. I would have paid for all postage too.
At this rate it is seeming the only option is to break the driver board to remove it. But I will keep trying.
James
Hey JR,
If I could get to the led board then I could just go around the led’s completing the circuit with a multimeter and isolate which one is bad. But I can’t even get that far. Getting the driver board out is the real issue.
Damn it.
James
Sorry, James. I misread a post and thought it might be the spring at the head end after all. I did not know about the spring being a common problem.
Hopefully someone has disassembled one before and posted pics but if not, can you post pictures of how far you can disassemble it?
For swapping the board you will need a soldering iron, and some crocodile clips to quickly make connections without having to resolder. This also means having two disassembled heads. :~
I wonder, can you buy a new head and save all this trouble? Or are you happy to try to repair it?
Hey,
All good.
Not sure why I would need two heads? Just need to get this board out and replace it with another one? There’s another guy on here that replaced his board and bhe didn’t mention needing another disassembled head…
I can post pics but there’s not much point, basically I have got to the point where the retaining cap is removed and the driver board is loose, I can pull it out part of the way but the coil on the side of the board sticks out too far to allow it to fit out of the hole. Either way, not much point removing it until I have another board to replace it with.
Everytime I try to post pics it wants a URL, meaning I have to upload pics to another site then link… seems BLF want to keep their bandwidth usage down… fair enough.
Ahh I will keep searching the forums.
James
If I still had my J18 I’d be able to tell you how to get the driver out. Reading another thread it seems the driver is pressed in by a retaining brass ring that is threaded. If you look at the bottom of the driver side where the spring is, you should be able to see 2 small holes/hollows on the brass retaining ring. If you’re lucky it won’t be fixed with solder or anti-adhesive.
Have you tried unthreading the retaining ring yet? Is there any solder used to bridge the retaining ring to the spring board? You’ll need some basic tools, I usually use SS tweezers. If after attempting this and it won’t budge, and you can’t see any solder bridging then I would use anti-adhesive as it may be glued.
Considering the amount of issues people are getting with the J18, it’s probably a driver issue as I couldn’t imagine the leds being a consistent problem, although I haven’t seen any resolutions yet.
You probably really need to upload some pics. I use photobucket.
Hey JR,
Definitely.
I have already undone the retaining ring etc… managed to pry the driver board out a little bit but the coil on the board is too big/on wrong angle to be able to get it out of the hole. Perhaps I am just being a muppet, but I spend lots of time trying. I tend to agree, it’s most likely the board.
I emailed the trustfire factory, hopefully they will come to the party with a replacement if I pay for postage - that would be awesome!
James
Hi, I thought you had two of the same light. If it were me, before ordering any new parts I would swap the head, then board just to make sure, hence taking two apart.
Good luck getting it apart! It sounds like a pain. :~
Imgur is good if you want quick pic hosting. 
Ahhh, I see what you mean Chloe - swap the boards to check if it is the board or the led’s… yes I have two of the same light.
Problem is I simply cannot get the board out… you would think that it would just slide out but it doesn’t. I have tried on every angle possible. It just doesn’t make sense. i can’t even begin to imagine how they got it in there.