What driver do I need... New guy...

Brian Ski

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May 23, 2014
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Indiana
I picked up a DX flashlight a while back. Worked well then quit. LED is not getting any power, so I am guessing the driver board is out. I don't want to spend a lot, because I am cheap, and it is a cheap flashlight. There are so many driver boards out there, I have no idea what to look for. I would be happy with a 2 mode. Medium and high. Doesn't look like they make 2 modes... Maybe a 3 mode...

The flashlight uses a 18650 battery. It is labeled Cree, Uniquefire, T6. Maybe something cheap on ebay??

Anyone give me an idea what I am looking for???
 

RetroTechie

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Oct 11, 2013
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Welcome to CPF, Brian Ski! :wave:

First I'd check it isn't a bad contact, loose retainer ring or something like that. Final assembly is often shoddy on such lights. :shakehead And check (read: measure) the function of any switches. For cheap lights, that's usually a single tailswitch.

Normally you can unscrew the front bezel & remove the reflector to get to the LED from the front. This may not be necessary though.

If you can unscrew head from the body tube, you'll find there is some metal ring that holds the driver board onto the 'pill' inside the head. If not soldered in place, you can unscrew that ring, using whatever fits (paperclips may come in handy :) ).

At that point it should be easy to get the driver board out. Measure its diameter, that's the size driver board you're looking for. The other thing to watch is the vertical room in that space between driver board & LED. For common drivers using AMC7135 IC's, that's usually okay. But for a high-power driver that uses 1 or more inductors (coils), that height may be a problem.

With the driver board out of the way, you can remove the pill itself (again, may not be needed). Or unsolder a wire to the driver board, and test the LED.

Doesn't look like they make 2 modes...
There's quite a few 2-mode drivers out there afaik. But mostly there's driver boards with more modes, that you can configure in different ways by making or cutting some connections on the board. For example to disable flashy modes (strobe / SOS) or choose between low-high and low-med-high. In some cases it's even possible to re-program the microcontroller on it. :duh2:

If you decide to disassemble the light, can you make a 'group photo' of the parts?
 

Brian Ski

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May 23, 2014
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Indiana
First I'd check it isn't a bad contact, loose retainer ring or something like that. Final assembly is often shoddy on such lights. :shakehead And check (read: measure) the function of any switches. For cheap lights, that's usually a single tailswitch.

Switch should be fine. I took off the head end and measured the battery voltage through the case/switch. good start.

Normally you can unscrew the front bezel & remove the reflector to get to the LED from the front.

Got that far and getting no voltage to the LED. Not sure how to test the LED. I am an old school and remember LED using 1.5 volts not sure what to power it up with. Didn't think I wanted to hook battery direct. To much voltage. Maybe a AA battery???

BTW Just for the heck of it I measured across the input side of the driver without the battery connected. I was getting about a volt. Guessing a capacitor on the board holding the voltage. Leading me to think the driver was bad.

At that point it should be easy to get the driver board out. Measure its diameter, that's the size driver board you're looking for. The other thing to watch is the vertical room in that space between driver board & LED. For common drivers using AMC7135 IC's, that's usually okay. But for a high-power driver that uses 1 or more inductors (coils), that height may be a problem.

If you decide to disassemble the light, can you make a 'group photo' of the parts?

Ok that points me the way. Will remove it and get a pic when I can... Thanks for the help.
 

Brian Ski

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May 23, 2014
Messages
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Indiana
At that point it should be easy to get the driver board out. Measure its diameter, that's the size driver board you're looking for. The other thing to watch is the vertical room in that space between driver board & LED.

With the driver board out of the way, you can remove the pill itself (again, may not be needed). Or unsolder a wire to the driver board, and test the LED.

If you decide to disassemble the light, can you make a 'group photo' of the parts?

Well... It looks like the board diameter is about 11/16 or a 17 or 18 mm... I put put a micrometer on it later. Fair amount of room above the board. Maybe 3/8".

Back to testing the LED. Not sure how. Being moderated for being a rookie so haven't got a reply to first message.

Camera is not good at very close up shots... Will give this a try. Kind of hacked the LED board trying to ge the pinched wires out. Ack...
2cnujio.jpg
 

Brian Ski

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Indiana
Well I put a mike on it... Looks like a 17MM diameter. Didn't know there were so many sizes.
 

Brian Ski

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Well I put a mike on it... Looks like a 17MM diameter. Didn't know there were so many sizes.

Ok 17mm... How do you tell what current driver you need??? Looks like I am narrowing it down.

Still wondering how to test the LED without blowing it. thx
 

LowLumen

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Jun 3, 2012
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To test the LED, put 2.5-3.0 volts across it & see if it lights up. I use a CR123A battery to test them.

For a Driver, do a search for 'NANJG 105C'. These are 17mm drivers using the 7135 linear regulator. Decide what the max current you want to drive your LED and order the driver with appropriate number of 7135 chips on in. (each 7135 supplies approx. 350mA, so 4 will drive the LED to 1.4A , etc. ) They con be configured to run 3 modes: 5%, 30%, 100% works well. If you want to drive more than 1.4A, the back side of the driver (facing the battery) will have 7135 mounted on it; make sure your light has enough room if you decide to use these. 1.4A & less has no components on the battery side of the board.

Good luck, hope this helps.


Edit: correction the driver with no components on back is 'Nanjg 101-AK-A1'
 
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Brian Ski

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May 23, 2014
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Indiana
To test the LED, put 2.5-3.0 volts across it & see if it lights up. I use a CR123A battery to test them.

Ah that is why it did not work with a AA...
For a Driver, do a search for 'NANJG 105C'. These are 17mm drivers using the 7135 linear regulator. Decide what the max current you want to drive your LED

Sounds good... How do you determine the max current??? How much is too much or too little to dim??? I would be fine matching the one I have, just not sure how to determine it.

Thanks,
 

Brian Ski

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Joined
May 23, 2014
Messages
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Location
Indiana
Well from what I can tell mine may have come with a 2800 ma driver. How much of a decrease in light will a 2280 ma driver be??? Noticeable???

Is there a rule of thumb or cross to current rating to lumen??? Suggestions or opinions??
 
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