The Kenometer at play...

[Curiously_Coherent]

Anyway, looks like someone, who is not as obsessed with perfection wants to buy mine, so it's possible i'll order another one, and hope for the best...

Make sure that you let DX know that you had the split beam problem and that you're willing to give them another chance. If you put in a support ticket and explain that you're selling your first one but would like them to check your second one for proper operation before they ship it, I'm sure Winnie will help you out. Believe me, they really want guys like us to stay happy because at $120 / laser we make up for a whole lot of $2 doo-dads they probably take a loss on!

I'm really glad if you found a buyer for the first one. TEM01 sucks when you know what it should be like.

Cheers, CC

 

[IgorT]

Make sure that you let DX know that you had the split beam problem and that you're willing to give them another chance. If you put in a support ticket and explain that you're selling your first one but would like them to check your second one for proper operation before they ship it, I'm sure Winnie will help you out.  Believe me, they really want guys like us to stay happy because at $120 / laser we make up for a whole lot of $2 doo-dads they probably take a loss on!

That's actually a good idea.. I'll do that, if i sell this one.. Thanks!

I'm really glad if you found a buyer for the first one. TEM01 sucks when you know what it should be like.

Yeah, if i didn't know what it is, i probably wouldn't care either.. The only thing, that would bother me then, is the bad beam divergence..

Let me know, when you get a chance, to check yours.. I would really like to know the spot size at a certain distance, for comparison..
And check the beam for splitting.. Oh, and is yours ever abruptly changing in brightness, noticably?

I would like to know, if better ones exist, before i order another one....



Kaidomain still hasn't even shipped the KD50, and it's been almost three weeks.. Every week they say it'll ship in a week. Oh well.
Since you have both, could you tell me the visual brightness difference approximatelly?


Thanks!



EDIT: Oh, i did manage to light one match from around 4-5cm.. But i had to paint it completelly black, and take the laser directly out of my cooler.. (a small peltier powered refrigerator for drinks)

And my mode hopping issue is changing.. Now it splits immediatelly, but slowly starts joining and turns into one beam in a few seconds..

If only the results were more consistent, it would be easier to decide, what to do..

 

[Curiously_Coherent]

I've just edited the original post with all the tests to add the two that I did last night and the videos I posted on YouTube. I was able to get 240mW briefly from the DX200 and it stayed at higher power for much longer while being cooled by a chill-cell. (Basically a highly conductive ice-pack)

My DX200 seems to have a nice tight beam and all I notice is that after cooling it seems to jump up in power in steps as the crystals warm up. I assume that the diode or crystals achieve some thresholds that kick the lasing into higher efficiency states. Later tests with used batteries would barely hit 100mw, so this thing definitely likes fresh Alkalines.

The KD50 has a nice bright beam and is easily as bright as the DX200 with used batteries. Plus it stays bright for a long time on that little LIon CR2. Speaking of KD, I just got an order from them I placed just a week or so ago, so maybe their shipping is improving. (Assuming the product is in stock, of course)

Here are the vid URLs if you don't want to bother going back to thread-top. http://www.youtube.com/watch?v=0aWEnjYW7Lw & http://www.youtube.com/watch?v=axQDsfdodXA

Cheers CC

 

[IgorT]

Here's some fun reading for you:

I went through that link, and i'm starting to get a feeling, that these lasers don't use the PD regulation at all...


Maybe, when they are regulated, they put out a certain lower power succesfully, but these could be hacked, to put out the max the batteries can give them..



Anyway, i noticed some more VERY bizzare behaviour... I thought the mode hopping has something to do with the current going through it, and the heat.. At least it looked like that at first...

But when i was measuring the output the last time, i got the feeling, the multimeter is interfering with the current flow.. The results were different, than when the batteries are inside and the laser is screwed together.. It started mode hopping almost instantly, and didn't want to return to normal.


Just now i measured the current again, with different batteries, and noticed something VERY surprising.. I can change the modes by varying the pressure on the pushbutton! This only works when it's taken appart, and powered from the batteries via aligator clips. When it's put back together, it works somewhat, but not that profoundly.. When it's appart, i can give it just the right pressure, to bring it back into TEM00. It becomes MUCH brighter in this case....


It would seem it has less to do with the current, and more with the mechanical pressure.. But i don't know how this is possible.. It only works on the pushbutton and nowhere else. It's really weird.


But now, while i was writing this, i had another idea.. Several people had incredible success by putting in Ni-MHs.. Maybe it has something to do with the length of the batteries pushing against the spring, coming from the PCB... The reason is obviously mechanical, so it is somewhat related to heat, and because of that also to the current, but it would seem, that my laser is capable of putting out only one very bright beam, at different currents and heat levels, if the conditions are right..

It's weird, but i'm gonna try putting in a tiny spacer, so that the batteries push against the PCB more, and see what happens...

 

[IgorT]

Success!

I fixed my laser!!! Finaly..


After discovering, that the beam varies the most with pressure on the button, i unscrewed the battery compartment, and looked into the laser module..

I noticed, that the spring is not in the middle before, but i didn't pay too much attention to it. This time i noticed, that it's moved more in the direction of the pressure on the button..

I removed the foam, that is hiding the "driver" board, and noticed, that it too is much closer to the opposite side of the laser body, and when you push the button, you just push it in that direction even more. There is a big transistor (or IC) on the other side of the PCB (opposite of the button) and it's only supported by a few more pieces of foam.


Since the "driver" board is directly soldered to the legs of the IR LD, every time you push the button you put strain on one of the most sensitive parts of the laser!

I decided to put a hard piece of plastic below that big transistor, so i cut two small rectangles from a 1mm thick plastic board and glued them together. Then i used a screwdriver to push the PCB up and put the plastic in place under the big transistor with tweezers.
Now the board is supported much better, and can not move with pressure on the button anymore. The spring is also closer to the middle...

I put the foam back around the spring, and put the batteries in. The behaviour of the laser changed dramatically!


Before, it liked being cold, started very bright, as one beam and mode hopped when warm, losing brightness.
Now it starts as two beams, but they immediatelly start joining, as it warms up, and turn into one beam in just a second or two..

Before, the longer it was on, the worse it got.. Now, the longer it is on, the better it gets! It gets to full brightness in just a few seconds and remains there! The abrupt brightness variations are also completelly gone! I tried with several different voltages and the behaviour is FINALY constant, as soon as it warms up.


Now i am happy with it.



One more thing.. Even if it worked perfectly all along, i would have prefered to have the PCB supported, so that pressure on the button can not break one of the LDs legs away..

I also think i know why most people get better results with Ni-MHs. It's possible, that rechargables are slightly longer or shorter and put a different pressure on the PCB through the spring.. I don't think it has anything to do with voltage or current anymore, except being somewhat related to it through the heat the current produces, and the resulting deformations inside, combined with button pressure variances.


The manufacturer should really build some support for the board under the button into the laser. It could be so much better if only it had this piece of plastic inside already..




Oh, i also just remembered the reason, the board is pushed so far down. There is another spring inside, going from the LD + up to the body of the laser, to provide electrical contact. This is what pushes the PCB down, and combined with pressure on the button and heat, causes the laser to malfunction.

It's a major design flaw, and all that's missing is a piece of plastic....




EDIT: I just wanted to add, that this fix, while it worked for me, could theoretically make things worse for someone else.. It might still be usefull in the long term, to support the PCB from below, but if everything works fine, don't bend it up like i did, just support it (so pushing the button doesn't cause strain on the LD), or do nothing at all.

Just gently supporting it on the other hand, could prevent it from developing this problem in the future...

 

[IgorT]

I've just edited the original post with all the tests to add the two that I did last night and the videos I posted on YouTube.  I was able to get 240mW briefly from the DX200 and it stayed at higher power for much longer while being cooled by a chill-cell. (Basically a highly conductive ice-pack)

I just watched the videos...


Are you also going to do the test with and without an IR filter? It would be good to know how much of the power comes from that.


Since my laser prefered being cold before, i really was thinking of converting it to active cooling.. But now, that it actually prefers higher currents and being warmer, i'm not so sure anymore. It's still not stable on alkalines, but it LOVES fully charged Ni-MHs...


On the other hand, the problem with mine is definatelly from some misalignment between the pump diode and the crystals. The conversion i was thinking about (active cooling and current regulation) would require me to use a completelly different enclosure anyway. And now that i know my laser is capable of making a good beam, i could probably fix this misalignment at the same time...

I didn't want to start taking it appart, before i knew, if it makes any sense at all, or if it would be better to return it. Now it looks like i could actually turn it into a very good laser... Hmm. But in that case i'll order another one, see which one works better and convert the other one.



I'm glad to hear you got your stuff from Kaidomain. But they still haven't shipped my KD50mW and it's been three weeks... Oh well..

 

[clwatkins10]

nice, wish i had one

 

[IgorT]

nice, wish i had one

Unfortunatelly, getting a good one is a lottery. I almost wish i didn't have the one i have now..

And even tho i did, what Curiously_Coherent told me to - i told DX about the problem, and that i would like to buy another one, if they test it, like i tell them to - i'm still worried about what i'll get.


On the other hand, they contacted me, apologised about the problem, and offered to follow my "test protocol"..


Now i just have to decide, if i really want it. I also don't know, how long i can keep this one in one piece.. My fingers are itching..

 

[Sokonomi]

Hi CC,

I just stumbled my way in here via a video I saw on youtube.

I have a question about the DX30 you reviewed.
Namely does or doesnt it come with a IR filter? DX seems to claim the lack of IR filters simply out of safety conveniance,
even though some people seem to report these things indeed having some form of IR blocking going on.

The other question would be is the DX30 in your test the "true" one, or another model?

Im still waiting on my first DXt30 coming on from hongkong, but I do enjoy reading some positive things on this unit,
as opposed to all the bad stories on the somewhat older reviews on DX. :

 

[Curiously_Coherent]

Hi Sokonomi,

Welcome to the forum. You'll find a ton of useful info here. As for the DX30, as I wrote in the test, I tested it with an external IR filter and it was still putting out 28mW, so I'd say it either has an IR filter or it leaks an insignificant amount. The only way to know for sure is to disassemble it, and understandably, I only ruin my toys if they stop working!

If you search here for DX30 you may find a thread where one was disassembled. Mine is a "True" model DX SKU 469 and it's been a good solid laser for me. I'm sure you'll enjoy it and I wouldn't worry too much about IR at this power level, just make sure you never shine or reflect it in your eyes.

Cheers, CC

 

[viroy]

if anyone has a working ken-o-meter they want to sell.
please let me know, i want one asap!

 

[Bionic-Badger]

Wrong forum section (you should post it in the "Buy, Sell, Trade"), and this thread is months old.