Small Red wire inside Firedragon "500mw" ...any ideas what it's for?

Hi,
I recently participated in the GB with Lasersman (aka Dino di-rectum) and received a real POS so called 500mw 532 Firedragon....long story short is it wasn't anywhere near spec and it had other issues like a broken spring, loose switch, cross threaded tail cap, and non TEM00 operation...they wouldn't agree to honor their return policy for a full refund so I am under dispute with them through my credit card company...chances are I will keep the refund my credit card company has already issued me AND keep the laser too...not that I want to keep their laser but unless they agree to pay for return shipping I have no intention to spend any more of my hard earned money to ship it back.

Having said all this I have decided to fix some, if not all, the issues with this laser myself and auction it off and use the money to help pay for the return shipping for some of the others in the GB who weren't so fortunate to have as easy of a time as I did with my credit card dispute, if there is any left over the rest will be donated to the forum.

So, now to the question at hand...this is the first high powered handheld green I have opened up and there is one small red wire that slipped out of a hole in the back of the diode housing. On the end was a very small dob of black plastic like material...the hole it slipped out of was filled with what appears to be heat sinking putty like Arctic Silver. The wire was bare for about 6-7mm above this black material and appears to have been in contact with the aluminum mount for the diode and the back of the diode housing..as if it didn't matter if it shorted to the body. The other wire going into the back of the brass diode housing is about four times the thickness of this red one and corresponds in thickness to a white wire coming odd the driver board that is attached to the body which I assume is the positive ground wire. So I have three wires off the driver board, one black going directly into the back of the diode housing that is firmly attached, one white going to ground/body, and the small red wire that was loosely slipped into a hole in the back of the diode hosing withe the sinking putty I described. My first thoughts is this is some sort of overheating protection circuit but this little piece of black stuff on the end doesn't appear to be any sort of thermopile (I guess it could be) and the wire was stripped up so high it it appears it was probably shorting into the body of the diode housing. Anybody have any idea what this is and how it should be implemented properly? I have not put it back together yet to see if it will work without this wire but I was planning to see what would happen if I taped it off and left it sitting in the back of the switch housing.

I am wondering if this wire being so sloppily applied and shorting into the body may have been the reason the laser was about 35% under spec and was so unstable.

In addition to these problems the spring was broken off and is now fixed as is the tail cap and loose switch....these were all easy fixes and are now better than OEM. Hopefully This wire was the cause of the malfunction and when I get it put together properly it will work as it was supposed to...who knows.

Any help here will be greatly appreciated.

In about 31 more days the dispute with my credit card company will be final and my refund permanent. If Lasersman doesn't arrange for the return shipping I will do as I mentioned and sell it. Not sure if I will go with eBay or just put a post here and give it to the highest offer. Either way, I will post a link here for those of you who are curious.

Also, if you are reading this and are one of the ones who got a bad laser from Lasersman on this last GB and will be out any money due to return shipping costs, touch base with me via PM in the next few weeks.

Thanks again for any help with this question...I wish I could post pictures but I am still having problems with my all Mac computers and file size limiting my picture downloads to the forum...I need to figure this out soon...

The RED wire with the plastic "blob" on the end is not really a wire, but rather a temperature probe.
- It WILL work without this wire inserted. Though I'm not sure if there are any other implications.

The other wire going into the back of the brass housing is NOT the positive lead. It is the NEGATIVE lead. It can be misleading, because often this wire is RED, even though it's the NEGATIVE lead. Remember that IR diodes are case positive, so green modules are generally case positive also.

The POSITIVE feed is supplied through the case itself.

BTW, awesome initiative you have here. I'm bummed that the GB didn't work out well for everyone Good on you for undertaking this to help out.

EDIT: If you're interested in testing the current to your diode (not tailcap current, but the ACTUAL current to your diode), you can place a DMM in current mode between the brass housing of the module, and the metal contact point it would connect to on the driver. Just make sure you have the DMM leads securely attached so that you don't break the circuit momentary and re-connect it, causing a surge. My FireDragon (300mW version) was shooting 2.4A to the diode itself.

Thanks RHD...my sentences are run ons so it kinda looks like I was saying the black was POS but I meant the White grounded wire was the positive ground....anyways, thanks for the clarification. So this wire just acts to transmit the heat to a thermopile on the driver board? Interesting....so it makes No difference if it is insulated or not I guess. In that case I will re-insert it where it came from.

I think I found the main issue this Firedragon was having....the spring coming off the driver board was bent down and wasn't making proper contact with the battery. Ultimately it failed altogether and broke off. This would account for all the issue sans tail cap I was having...low output, fiddly switch, unstable output, and I suspect, mode hopping. When I fixed the spring I used a slightly larger gauge wire spring and instead of just soldering it to the board I also used some five minute epoxy to strengthen the mounting of the spring. The switch housing is on the end of the driver board that the spring was mounted and explains why it took constant pressure on the switch to keep the output high....this was applying indirect pressure onto the spring making the contact with the battery better. I suspect when I put it all back together it will perform much better.

Since my very first test I was unable to replicate the 420mw output again. I will bet it will be back to that level now. Still shy of the advertised "we guarantee you get more than what you pay for" 500mw but maybe not...soon we will find out.
Jeff

Hey,

Not a "thermopile on the driver board". I'm fairly certain it's just a thermistor or something, that sends its input back to the driver. Though admittedly, I might be wrong - if it's a single lead, then it doesn't make a whole lot of sense for it to be a thermistor.

What I do know, is that you can run it without this item inserted. In fact, I have a super awesome build that will confirm this for you if you want to scope out a thread I'll be posting, hopefully later today

Any luck re your output issues?

Yes, I am interested in your thread, please post a link here if you don't mind.

I still haven't put it back together. I caught a nasty cold the past two days and just haven't been up to messing with it. As soon as it goes back together I will post some new LPM runs.

Even if I fix it I am going to sell it (provided it doesn't get returned) as I bought a "1w" green from Laserpointerpro a couple of months ago, knowing it wasn't going to be a full 1 w but the price was right...it ended up being a stable 430mw with good batteries and has much better beam specs than this one...the beam diameter is more than half of this one here....it is much brighter than this one so I am keeping it instead (I originally intended to return it but for $200 it turns out to be quite a nice build). I doubt unless this one can pump a stable 600mw or more, that it will appear any brighter than my LPP build. It's also in the exact same host....