Quark AA2 died - DIY fix possible?

My 8 year old Quark AA2 ( R5 Edition 1 - according to the invoice) has just died. Not unexpectedly perhaps. Forgot it was in my lap and it dropped about 2 feet onto a wood floor when I got up from a chair. The problem appears to be in the head since the batteries and tail switch test OK.

I would hate to just toss it out so I thought I'd take it apart to see if there was a clip, or contact or solder joint that may have loosened/mis-aligned. Is that even a possibility? Trying to disassemble the head I got as far as what's shown in the photos. Can the pill(?) be popped or screwed out? If so how exactly?

At the moment I'm somewhat wary of going further since at this point nothing seems to come apart easily. I'm particularly concerned about breaking the solder joint of the white wire to the aluminum tube. I haven't been able to find anything via google or the CPF forums for this particular model. Any thoughts, instructions or information sources on how to disassemble it would be greatly appreciated. Many thanks.

Regarding the "photo"mentioned above - I guess as a new member I cannot attach photos and I do not have a URL source set up. So, I'm looking at the LED emitter end of the head assembly - black plastic centering disk removed - a white disk with a led and a red and black wire soldered to it - a white wire coming from below this disk soldered to the aluminum head tube.

Can now edit post. Photo links follow:

I'm not 100% sure but I think the 4Sevens lights had a 10 year warranty. Check https://darksucks.com/pages/warranty-returns and see if it qualifies for repair.

Update: I checked the wesite and it looks like DarkSucks will do some repairs on older lights but you pay for parts and labor, depending on when the light was purchased.

PJ said:

I'm not 100% sure but I think the 4Sevens lights had a 10 year warranty. Check https://darksucks.com/pages/warranty-returns and see if it qualifies for repair.

Click to expand...

Didn't 4sevens go bankrupt? AFAIK, they're no longer in business. Whoever took over their brand name, probably won't honor the warranty. But, I guess it doesn't hurt to check. I threw out my receipts for my 4sevens lights when they went bankrupt.

Thanks. Have checked that. For purchases pre 2017 (mine) there are labor and parts charges. Plus, living outside the U.S.A. the shipping costs would be several times the value of the light.

Nica, would you be able to PM the pictures of the flashlight? Also, do you have access to a multimeter that you could use to test the different paths on the circuit to see if there's anything you can find that way?

Wow, I forgot all about that warranty, my Quark AA Turbo goes everywhere with me but I think I bought it pre-2008.

Try tighten the clip ring.

Thanks. Tried that. Wasn't loose to begin with. Still no joy.

Try paper clip as a tailcap.

I would start by cleaning the threads up real well and then lube everything up.

If you have a digital volt meter, you can check for voltage at the led. If none, then it is a problem with the board. In my experience when dropped, sometimes a component, usually the heaviest one, can loosen or break off entirely. The rectifier (?) I think is what I've seen go.
Theoretically, it can be resoldered, although I haven't tried personally.
To alleviate this, the board needs to be potted, to hold all of the components static, even when subjected to a sharp blow of some kind.
if you shake the light, do you hear anything loose?

There was no voltage at the led. And all continuity checks in the host and tail switch checked OK. After de-soldering the led leads and testing with an independent power source it lit up. So that leaves the driver.

Cereal_killer helped me through the disassembly which wasn't particularly intuitive (at least to me, first time taking a light apart). The aluminum "disk" under the led star is not a press fit (or other-wise) heat sink. It is a solid machined part of the head. The driver is also glued/epoxied into the head. C_k said the only way to pop the driver out would be to go in through one of the wire lead holes with a sturdy "pick" and punch the driver out, probably destroying it in the process.

I used a very small micro screwdriver inserted at an angle through the screw hole (photo below). This penetrated the furthest and seemed to make contact with the large driver disk. Going in through the wire holes only reach the smaller upper disk. Given its somewhat iffy connection (unknown at the time) to the large disk those points probably wouldn't have been useful in punching out the driver assembly. I also half submerged the head in boiling water for about 15-20 seconds. This wasn't so much to try to soften the glue/epoxy as to have the aluminum head expand faster than the PCB and crack the glue joint. Anyway, a sharp tap on the screwdriver and the driver popped loose.

As for the failure of the driver... the only thing my untrained eye could see was the "thingy" connected to one of the "half-moon" contacts on the flip side of the large driver disk had broken free (see red arrow in photo below). Maybe it was due to the fall, maybe the boiling water, maybe it was something else entirely. It's beyond me to fix it so on to a new driver an led.

Since this is my first go at this, any suggestions. The info in the forums (and others) is overwhelming. I was always happy with the original specs of the Quark AA2 - 180 lumens, 7 modes (especially moonlight), Cree XP-G R5, used daily/nightly and only had to re-charge batteries every 3-4 weeks. So I don't think I need the latest and greatest, but am open to suggestions (as long as I don't burn my fingers).

Looks like an inductor has broken or come loose. That shouldn't happen from boiling water, it was probably due to the fall. Inductors have a fair amount of mass (being a chunk of ferrite with copper windings around them) and a common failure point in my experience for a driver subjected to large shock. If the inductor is still intact, you can try soldering it back into place.

zipplet - from your description (and google) that's what it looks like. The coil cracked off leaving a very ragged break above its solder joint, or however it was attached. It also looks like two very fine wires leading from the coil to the two half moon tabs at the point of the red arrow also broke off. That's micro surgery to reattach or replace and beyond me. A new driver still looks like the best option.

Before you give up and consider a new driver. Try the baking the driver in the oven 100 degree Celsius fro 20 minutes. I did that with one driver, when it wouldn't cycle through the modes anymore. So i got moonlight and nothing else. I checked everything without success. Short before purchasing a new driver, I gave a short with the oven. The result was that it works again. Not sure for how long, but it is now a couple of weeks ago and i use the light daily. So somehow the heat must have "reconnected" the part that broke or got disconnected. But again use this as the last option when you would anyway through it away

If you can get the iron onto the pads, there is a reasonably safe way to attempt a fix.
Peel back the winding so you have a small amount of wire exposed at the bottom of each "pad" of the inductor. Scrape off the insulation a little at that point with a flatblade screwdriver/sandpaper - it's enamel, so only gently. Make sure the wire is extending a little beyond the bottom of the inductor.

Apply solder to each pad. A small blob is sufficient.

Apply flux to the inductor and pad.

Hold the inductor in place and heat one side of the joint. It should attach firmly. Then do the same to the other side.