DX 200

Yes, someone over on CPF has taken it to school, and done a spectral analysis, and when hooked up on a power supply it was 178mW of green and around 30mW of IR or so.

The burning power can not come from the IR, as it is not collimated at all. The reason, that it only burns at short distances is the divergence. These have a very bad divergence usually, so as soon as the beam becomes wider, it can not burn anymore, because the power is spread over a larger surface.

What kind of paper did you try burning? What did you paint it with?
Oh, and did you check it for mode hopping through a magnifying glass?




I just got the second one as well, and guess what.. It's mode hopping, as soon as it gets warm.. Again!

This one has a better divergence, than the previous one, so it can burn further away. Unless it's mode hopping of course.
While in TEM00 it can light a match very quickly and etch a black floppy disk. But as soon as the beam splits the power spreads, and it can't do this anymore.
This is also very noticable in the brightness of the spot. In TEM00 it glows, but when the beam splits, it instantly loses brightness. Almost half of it.

Through a magnifying glass, i can observe, how the big spot starts turning into an elipse, and then two spots still joined, and in the end two completelly separate spots.

I tried alkalines and Ni-MHs and nothing helps. The PCB wasn't even supported by the foam this time, and the button gets stuck sometimes.
If the module in the middle was more massive, the heat could spread more easily. Instead, there is air between the module and the body of the laser. If only the module was thicker, so that it would touch the outer shell, this could be a good laser.


This is so annoying! Rain from DX tested it for me - he said it was "always bright", and they wrapped it in extra bubble wrap like i asked, but the quality of these is just too low. All in all it's a bit better, than the previous one, but if only the beam would stay in one piece. It's depressing.


I did notice, that the module would fit into the massive body of the KD50. They are identical in size and both have threads in the same place.. I think i'll put my KD50 in the body of the old DX200 and the old DX200 in the body of the KD50, so it has better heatsinking. As soon as i'm done repairing it..


I think this one is going back tho... Don't want to wreck my nerves trying to repair another one. Especially with unpredictable results.

I can't believe, that i ordered two and got a bad one both times.

Sorry to hear you got burned again Igor. :'( Maybe they just aren't making them like they used to anymore. I think you should take a little video of the Mode-Hopping as seen through your magnifying glass and send it to Rain so he knows better how to test them there. Maybe it can help them sort out the quality control before they get shipped and spare others your experience.

My condolences. CC

So what is the actual divergence, what approximate beam diameters for both green and IR at 1 - 5 - 10 m ?

Well, i have a few weeks, before i have to return it.. I think i'm gonna build an attachable Peltier cooling module and stick it on, to see what happens. Some cooling wouldn't hurt it, but i noticed, that putting it in the cooler actually brings the output down, below the KD50.. The previous one liked being cool. This one prefers being warm, but not hot.

At the moment, the mode hopping is gone, but the brightness is changing. It's very weird. Sometimes it drops and then it jumps up again. At one time it was actually almost blinking quite fast, between low and high brightness.

When it is at high brightness it's great, but it's unpredictable.


In this one the PCB was even weaker, and pushing the button bent it down so far, that the button almost fell in. I supported it, and it seems a bit better now. But there are so many design flaws in this laser, i don't even know where to start....


Well, at least i won't be sorry i ordered the 150mW CNI.

Well, it just wouldn't be a DX200, if it didn't start working all of a sudden, just so that i would doubt my decision to return it..

The mode hopping is gone. It only happens, when the batteries are charged too high. As soon as the battery voltage drops a little, and with it, the current, since these are not regulated at all, the mode hopping is gone.

This means, that if i would replace the driver, and set the current just below the mode hopping current, this problem would be gone..


I had an idea, where i would make a battery shaped addon driver, which would contain two AMC7135s and would be put in the battery compartment together with an AAA size Li-Po. It would have a spring, to make contact with the body, for the +, and two contacts on each side, one to touch the battery negative pole, and the other, to touch the spring of the original PCB.

This way, i would not have to take the laser appart, but would still get current regulation, and constant output power, over the entire battery voltage range, as it discharges. This way, the brightness wouldn't be dropping together with the batteries and it would work from a single Li-Po cell at a high efficiency.


But there is the problem with the changing brightness. When i power it on, it doesn't gently increase to full power, but jumps there in a few quick steps. Between steps, there is a short pause, then it jumps up again. It's really odd.

I could probably live with this, if it didn't start doing these jumps up and down later.. It would seem it stabilizes after a while, but it's very annoying.


I have to resist the urge to take it appart!!!!

It's gonna be very hard tho, since putting it into the KD50 body seems so tempting...



EDIT: Correction.. When i power it on, it doesn't just increase in steps. It comes on at a medium brightness, then the brightness starts gently decreasing, then it suddenly jumps to higher brightness. Then it stays there for a while, and then it again starts gently decreasing, it jumps up even higher and stays there for a while. Then it gently decreases and jumps even higher. After three or four such steps it reaches the maximum brightness and stays there, if i'm lucky.. If not, it starts jumping down and up again.. This is very confusing..

I have succesfully resisted the urge to take it appart long enough, to arrange a replacement.
They say third time is the charm...


I sent them even more pics of how to test these, and i hope they don't just say it's a good one again.
I'm also starting to get the feeling, that both DX and KD have a bunch of returned lasers, which they simply try to sell again, untill someone keeps them. They probably put the returned ones on top of the pile in the warehouse.


The pic shows what my second laser does after warming up and the spot on the wall when pointed through a magnifying glass.

Hiya Igor,

Going for #3, eh? Good for you! I, for one, appreciate you helping to train the DX staff in laser testing as well. [smiley=thumbsup.gif]

Your picture of the mode hopping is wild. I've only ever seen 2 blobs, but it looks like you've got 4 there! Freaky.

Thanks for keeping us posted, it'll come in handy when I get around to fiddling with mine again.

Cheers, CC

Does that mean yours hasn't recovered after bending the PCB up?



Yeah, it's wild. The previous one split into two beams, but very quickly. This one is stable for around 30 seconds, but then it splits into five beams! There is another, smaller spot between the last two big ones and they're not as neatly arranged, as it would seem in this picture.

When requesting the RMA, i sent them the above picture, and the one below, to help with testing. You can see the flat split beam entering the magnifying glass, and then spreading, till it makes that ugly blob on the wall..

I also sent them a video of the beam splitting, once the laser is already warmed up. I really hope this helps with them finding a good one for me. I also told them, they don't have to refund the return shipping, as long as they make sure i get a working replacement.


But i doubt it'll help much with the quality of these lasers in the future. It's impossible, to test each and everyone thoroughly. They probably just turn it on for a few seconds, and if it glows, it's good.


I don't blame them for all these problems. I'm guessing, these lasers were actualy better at the start, but the manufacturer found a way to make them cheaper, thereby causing all these problems. Or maybe i'm just extremely unlucky..

I just returned a DX200 greenie I just got which was mode hopping out of the box. In the rare moments it didn't hop, it would pop any colored balloons from 6 feet away, instantly. No black marker dots required.

I was offered credit for the return and will be getting


2 of SKU-7884

&

1 of SKU-11315


I won't buy another pen laser again, period.



TS

Looks like these really are getting worse.


How long did it take yours after power on, till it started modehopping? Oh, and did you try it with Ni-MHs? They are much more stable on them.

My first one would do it after only a few seconds while the second one could remain "stable" for as much as a minute, when it was cold around, but usually 30 seconds...



I just want to get a stable one, to mount it into a different host with a MUCH better heatsinking and a proper driver.

This way it could actually become a great laser. The one i have now only splits when very warm, so i know it would work nicelly in a more massive body. If only it didn't have the abrupt brightness changes...

Mine mode hopped within 1 second of turning on. The barrel gets warm quick! The PCB stuck too far out and when the battery compartment is screwed on all the way, it compresses the spring all the way back and into the board. I tried NiMH's and got a few seconds of obscene performance. But not worth all the crap to get a good stable laser out of it.

I've heard great things about SKU-7884. So I'll try that.


TS

The SKU-7884 looks the same as the KD50, which is a good laser. The KD50 has some contact issues, which can be solved by cleaning the metal and a little soldering. After that it can turn into a great laser. The 7884 looks like it has a better heatsinking at the pump diode, and a more rigid construction around it. Hope you get a good one.

If your first DX200 started modehopping immediatelly after power on, it is very similiar to my first one. The second one is a little better, if only it wasn't for the weird abrupt brightness changes during warm-up. If i had a choice, i would return the first one, but it's taken apart, so i can't.

My worst fear is, that the replacement would be even worse. I'm trying to explain to DX how to test it, but i'm not getting the response i was hoping for. I really hope Rain answers the e-mail i sent him. So far he hasn't made a sound.

After reading the early stages of this thread, I decided to get the DX(NewWish) 150 instead. For me this was a good choice. My 150 is rock solid. In fact, I have been trying to better focus the darn thing and have run it for a straight 2 minutes with no mode hopping or power drop---now this IS with the module out of the case, simply taped to a table.. It got warm, but not terribly warm(maybe 90 degrees F). And that is powering it with 2650mah AA NIMH's!

The 150 is a keeper for me, until I can afford a REAL laser. Too bad the beam divergence sucks(at best 3-4mm at 12m) and I can't seem to solve the corona problem.

EDIT: The 150mw is the same construction/driver as the 200mw(comparing mine to the pics at the DX200 webpage)... makes sense after reading the NewWish spec thread. My guess is the lower power coming from the same components(seemingly because of the crystal) means more stability. With either one, BE SURE to support the driver board from underneath... my 150 did not even have foam under the board to protect it from the pressure of pressing the button.

which sku # is it?

Actually mine came from Kaidomain.. but is a newwish just like the DX lasers.

Here is a link:

http://www.kaidomain.com/webui/ProductDetail.aspx?TranID=1361

SKU at DX is #1998- same laser I bet.

Your looking at a true 50 that made it to the 150 bin ;D