Instructables
Picture of led flashlight repair
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 UPDATE .....MAY 7, 2012
To my grandson Braydon....
I started having issues with a short again, and this time found the battery holder positive terminals were "collapsed" at their mounting point in the plastic holder, preventing the battery itself from making contact.  There were three very small screws to remove from the end of the battery holder, allowing removal of the holder's end cap, and therefore access to these terminals.  A miniature slot screwdriver was used to gently pull these out a TINY amount.  This allowed the batteries to make proper contact and corrected the 'shorting' problem. Light is working great again !  One 


I bought a package of 2 'tactical style' small flashlights from Home Depot for roughly $10 US.
They are great, powerful little lights, but within 2 weeks started shorting out during use. Very annoying.  Thinking it was a bad on-off switch or a loose connection to the batteries, I started snooping inside the thing.  What I found was a worn spot on the heatsink, at the point where the battery holder 'nose' or 'nub' connector makes contact.  If you'll look in the photos you'll see the tiny worn place on the heatsink, which to me looks like it was spray painted on with a metallic-like paint. That's over simplifying how it's constructed, I'm sure, but you'd agree, I think, if you saw it with a magnifying glass, as I did.  Solution was to drop a small amount of solder into the center of the heatsink, creating a solid area for the battery holder nose pin to make contact. Worked like a charm.
Step 1,     disassemble. Unscrew the front end-cap, revealing the silver colored head you'll be working on

Step 2,     unscrew the head from the after-part of the flashlight.

Step 3,    turn the head on it's  side with the led light down,  exposing the back side of the heat sink where the trouble spot is.
                I've supplied 3 different shots of this, and if you'll look at dead center of the heatsink you can see a tiny worn spot.
                Look closely and you'll also see a tiny hole towards the edge of the contact area. I'll assume this is a source for ventilation
                 to help the heatsink work best.  During soldering, you'll want to avoid covering this hole with solder.

Step 4,    First, drop a small bit of solder onto the center, (2 pics of this step)

Step 5,    using your soldering iron, spread the drop of solder around just a bit. (another 2 pics of this step)


                You're done ! Except for re-assembly, or course. I'll trust you can do that without pictures.
One last tip.  When putting it back together, I like to use a lttle lube on the threads, in this case, good ol' vaseline!
arkville2 years ago
Excellent presentation. Repaired my LED quickly by using your easy to follow instructions. Mine was slightly different in that it had a spring in the center of the rear and the spring had come loose from the pc board. Resoldered spring to board and light works perfectly.
bobcat1947 (author)  arkville2 years ago
Your remarks are very much appreciated. That was a fun and relatively easy fix, and I was fortunate to have a camera that clarified things, too.
reptilehead2 years ago
THANK YOU!
I carry a Leatherman Monarch 400 (part of a leatherman gift set) and it was having that same issue, 30 seconds after getting it disassembled, I had it fixed!
bobcat1947 (author)  reptilehead2 years ago
Thanks for taking the time to let me know, RH ! Did yours have a similar heat sink, with an easily worn spot? Just curious. I'm fascinated by the development of these type flashlights.
Very similar, the only difference being that mine didn't have a hole on the back of the heatsink/PCB, and the whole unit was internally threaded.
It also only runs on 1 AA battery, its not as bright as my other multi-LED lights, however the BEST light is the one that's available at all times, and this one is small enough for my E.D.C. pouch.
Phil B2 years ago
Thank you for this. I looked at your 6th and 7th pictures (from the left) and noticed one of the little metal tabs coming up through the green circuit board material is not soldered to the board nearly as well as its companion. I would want to add some solder to that joint, too. (The joint I have in mind is toward the right side of the circuit board.
bobcat1947 (author)  Phil B2 years ago
Thank you, Phil. Good eye ! I opened up both lights again, and they each have that same imperfection. There's an unopened pack of these in my drawer, and I'll bet they'll be the same.