The hot melt glue stuff picked off easily on mine. It draws only about 200 mA with a charged cell. The pump should take a little more if turned up (somehow !). This may help mode hopping as I've noticed that it's worse if the battery charge is low.
Also, without the glue, I may be able to rotate the LD in the housing for better coupling.
Btw, i've noticed none of the thermal issues you describe, mine comes to full power within a second if its just at room temperature (around 18 centigrade here currently). If i leave it on for a few minutes it does warm up and dims a bit, but not severely. I have noticed the mode hopping problem once, but on a nearly drained cell... even then it did that for a split second and then produced the normal beam again.
There are 2 resistors, one 1k (102) and one i can't read but might also be 1k. The PCB has a space for a pot there, but i'm not sure what value it should be. You could try putting a resistor in paralel with either (i'd experiment with 4k7 or so), and see if that has an effect on current.
The marking 'power transistor' is my mistake - it's acutally an IC, but looked like a SMD power transistor initially because its coverd by the glue.
I noticed that if my KD 50mW got cold, the intensity dropped significantly but no mode changes.. it seemed to warm up on its own to full power but it would take a few minutes. I also noticed that the power switch seemed flaky. Sometimes the power would flicker or dim if I barely toched the switch. In my case, the problem turned out to be where the switch terminals were soldered to the case. The solder connections were cold. After fixing the poor solder job, the switch worked fine.
The pictures show the two spots where I had to re-solder the connections on the power switch. The picture was taken a few weeks ago before the laser was sent back as defective. I'm still waiting on KD to replace it..
For some odd reason, there is an isolating gap between the actual body and the diode/mca assembly. When closed, the metal ring on the end of the lens provides electrical contact, so it will not work when opened up. I put some braided wire in the gap, which allows it to work open, and makes adjust focus a lot easier.
For the sake of thermal- and electrical contact, closing the gap would be a better choice. I don't dare to solder the pieces together though, as the heat may very well damage the diode, mca and what not. I did leave the wire in there when i closed it back up, it provides and addtl path for electrical contact that way.
It could be that they are still held together by the glue in mine... doesnt feel like a very solid connection, but it could also be held there by the laser diode leads - so i don't feel like yanking it out
My KAI 50 died tonight... It was only on for about 4-5 minutes as I was experimenting with trying to burn some ink black paper (the paper never burned, smoked or complained).. It was lasing fine and then just blinked off....
I was still using the original battery so I replaced the battery and measured the current draw at ~225mA, still no lasing. I left it turned off for a couple hours and tried again....It's definitely malfunctioning as there's nothing green coming from the aperture. There is a faint deep red glow (yes, I know..IR) but that's it.
I took delivery of the laser on November 17th and I don't think it has more than 45 minutes total run time since I've had it. The beam quality was always good but I don't think the power was close to the "true" 50mW claimed. It couldn't do any of the tricks you might expect but it did have a nice looking beam for star pointing.
Oh well.. It has a 30 day guarantee. I sent KAI an email; I guess I'll find out what kind of customer support they have.
In the meantime (and to make myself feel better), I just ordered the 90mW UltraFire laser from DX.
My replacement laser finally arrived today. After first powering it up with the provided battery, the power was about 17mW. After disassembling, I cleaned all the threads and the entire case insides with scotch-brite (anywhere that could be a power coupling). I also re-soldered the switch contacts to the bottom part of the case. The stock battery measured 3.05 volts with no load. After reassembling, it was much better. 51mW @ 265mA! With a freshly recharged CR2 @ 3.8V, the power measured 79mW @ 417mA! Very bright! Let's hope this one lasts a little longer.
I canceled my order for the Ultrafire 90mW.. It appears to be on indefinite back order.
I got mine today - And it came with a CR2 Lithium, giving out whopping 0.2v!
I did a little "mod" on mine, not really a mod, but i connected two AA-batteries with some wire and tape, gonna make it permanent (with real battery holder and such, in a box) later, because one CR2 battery cost just over $9 here.. AA batteries cost $0.36 for one.
First toughts was that it was bright! I think it is brighter than my true dx30 (but i cant check now, because i dont have any new batteries - just old crappy ones)
Re-charging a primary lithium cell? At the very least, i'd suggest better eye protection than you would use for using the laser
417 mA sounds like a lot to mee to, mine draws around 300 mA from a fresh rechargeable. I can't measure output power, but i'd say it's pretty close to the claimed 50 mW from the rechargeable. From the primary it's a bit less, somehow laser manufacturers can't seem to create a decent current source. This still surprises me, it's not that hard to get it right, especially when you -can- get the rest of a DPSS laser right.