DX 200

[IgorT]

The DX 50 and the 200 are identical, the difference is some put out only 50mw and some put out higher. After they build them, they are just sorted into three catagories. Same pumps, same crystals, same optics, the ones that work better are just sold at a different rating. This is how they sell without wasting the lower output units.

Ah. I understand now. Before, i thought they were supposed to be lower power, but the better ones get sold as more powerfull ones.
Thanks for your answer! Clears up a lot!

The crystals I purchase are from a guy on ebay in Australia, he has them for sale off and on but there are other suppliers availible.

How much do they usually cost? I've seen some expensive crystals on e-bay, but i have no idea, what power they are meant for recieving and putting out, as it is not specified.

With the true 50, I have gotten 100mw simply by adjusting the the housing which holds the crystal, not changing it at all.

To get the most power out of my DX200, i also have to bring the crystals so close, that they are almost touching the diode, and the diagonal of the crystal has to be aligned with the fast axis of the diode.

The weird thing is, that when i got it, the crystals were further away, yet it was putting out more power. Now, the power is pathetic in that position, but i can get close using the mentioned alignment.

Also using optics between the pump and the medium is only nescesary when using closed can diodes. The true 50 has an open can 9mm multimode.

I know they only use collimation with the lower power units, but i think the power of the 9mm pumped lasers could also increase, if the fast axis was collimated. If i look at the output of the diode alone (through a camera), i get a very long narrow stripe. If this axis was collimated, the amount of IR going into the crystals would increase.

Is there a reason, why open cans don't need fast axis collimation?

The true 50's can be adjusted and are not glued, adjusting it can eliminate mode hopping. The crystal housing is threaded and the slightest movement during shipping can knock it outta whack. YES MODE HOPPING CAN BE CORRECTED!

I know. I was able to elliminate it from a laser, that would otherwise split into two beams in just one to two seconds after power on.

Your DX50s didn't have the crystal nut glued in place?!? With my DX200 the crystals were glued, and i had to break the bond before i could turn them.

The only problem is, if you get the crystal in a off center position and the pump hits the edge of the crystal, you can burn up the pump from reflection and or burn up the crystal. It takes some practice and IR goggles for protection, and the death of a couple of units on occasion. This is why I started with DX units, as they are the cheapest  to practice on.

I put my first DX200 through A LOT of torture. But it's still alive and well.

I even managed to bend the pin of the open can on the inside, where the three hair thin wires go from to the chip. I have no idea, how i bent it, but i bent it back, and the thing still works!

I had to make a special tool for turning the crystals with the laser pointed away from me. It also holds them in place once i find the sweet spot, long enough, that i can glue them in place again.

But i decided against further experimentation untill i get my LPM. I can make it very bright, but it's impossible to get the final few mWs out without it.

I did manage to reduce the possible alignment combinations down to four. It's gonna take a lot of patience to find out which one is the best, since both the crystals, and the rotation of the pump diode have to be adjusted at the same time, but since i found the diagonal alignment, my results are much better than before.



Anyway, i really appreciate all the usefull info, you shared.

So do you think i should go for two True DX50s as a replacement for the bad DX200, and just try making them better? 120mW sounds great, just from adjusting the alignment! Is that with two AAA cells, or a proper driver?



EDIT: Oh, one last thing.. Did your lasers say NewWish on them? The TrueDX50s i mean?

Also, did you measure the current they consume? With the DX200 i have measured up to 730mA with good batteries.

 

[MarioMaster]

adding a lens in front of the pump diode would probably help - the 200mW lab laser i have has a high powered Cmount diode with a collimating lens that focuses the energy onto the crystals - the problem is the space constraint inside such a small laser

 

[laserrod]

Hi guys,
I bought a 100mw DX true Laser and it didn't say NEWWISH. COM (it should have)on the copper pump inner screw just mentioned.
I complained to no avail. That laser lasted 1 hour under expert care!

I believe the safe maximum current for 200mw Dx lasers is .5 amp.
I would like everyone to post thier current(power your laser though DVM or V/A across a resistor) and succsess/happynes with thier 200mw Dx.
I found my pump blew at about .5 amp.

Also, I found because the voltage is so low and the amps high that a bad connections cause current & voltage surges to the pump diode that makes it blow. Make sure your connections never short to the copper body of the laser and cause nasty highvoltage/overcurents that do pump diode failure.

I suggest the Eneloop NiMi batterys after testing alot of other rechargables. Batterybob.com
Now the great GAZZO should apear(post something) hopfully to endorse Eneloop's as I did.
There Greeeeeeeeat!

Cheers

Testing current is easy;
Clip one end of Alegator clip jumpered to the unscrewed laser head and the other clip cliped to the threads of the laser body holding the two AAA batterys
then complete the circuit through you digital volt meter configured for measureing amps through the test leads.
One lead to laser head spring and the other to neg flat end battery exposed from open end of battery tube. Use a tiewrap or whatever to close the pushbutton switch on the laser head.

 

[GooeyGus]

Well... upon closer inspection today I found the issue with my true 50. The crystal seems to have some damage on one of the corners. I'm pretty disappointed that this "true" 50 doesn't say new-wish inside at all. It really makes me wonder what DX is trying to sell. I'm thinking of ordering a standard 50 and see if there are any differences. Anyway, here is a picture I snapped of the crystal.

RIP :-/

 

[IgorT]

Wait..

You have collimation optics between the pump and the crystals?!? Looks like you burnt away the edge of the crystal while turning it. Is it off center?

Wannaburn said the TrueDX50 is the same as DX200. There are no optics in the 200. And this picture looks much different from what i found inside. That's what the regular 50 should look like, not the True.

Is the diode a 9mm open can?


This is starting to become confusing. Looks like DX actually switched the manufacturer from NewWish to someone else, but they still say the lasers are "genuine NewWish" on their page.

 

[IgorT]

I believe the safe maximum current for 200mw Dx lasers is .5 amp.
I would like everyone to post thier current(power your laser though DVM or V/A across a resistor) and succsess/happynes with thier 200mw Dx.
I found my pump blew at about .5 amp.

In the first one i measured between 450-550mA with Ni-MHs, but i tested it with up to 600mA on my PSU. I set the voltage to 3V but luckily limited the current, and the voltage actually dropped to 2.3V to compensate.

Since i read about others measuing up to 700mA on Ni-MHs, and Lithiums should provide even more, i tested the second one at up to 780mA peak, dropping to 730mA and stabilizing there for a while (When powered by a 3V Li-Fe-Po.


Both of the pump diodes still work good as new, but the rest sucks...


I also noticed, that powering the laser through a DMM severelly affects the results. Since there is absolutelly NO regulation in these lasers, a DMM can make it hardly glow at all, even in the 20A range, where the shunt is just a thick metal rod!

I would imagine, the currents without a DMM in series are actually even a little higher than measured, and when measured, they depends greatly on the DMM and the selected range. I found more than 100mA difference between 20A and 2A range.

 

[GooeyGus]

Yes its a 9mm open can, there are no optics between the crystal and the pump diode. I had to take the picture thru a lens to be able to get the macro shot of the crystal

 

[IgorT]

Oh, ok.. Thanks for the clarification!

 

[JLSE]

I have crushed both crystal and the tip of the diode trying this, usually with an 8 out of 10 success rate. It can be tricky, but the idea for me has been to get the crystals as close as possible even touching on occasion. A guy I buy 1watt pumps from also advised me to peel open his diodes for maximum values. Even the cheap "5mw" green bare modules from newish perform better when you peel off the can and remove the two lenses. I’ve gotten 50mw from a few of those. From what ive experienced, id say the lenses rob power. Mind you I haven’t tried using expensive optics between the pump and the medium, but this way has been working well for me. All the trues that ive bought are not labeled newish either. I think it is the same manufacturer as the labby 35 and 50/100. When you try rotating the crystal, keep in mind that there feels like a stop when you tighten it down. In many cases it can be turned further than that, but glue on the threads stop it. Try turning a bit further, just not if it feels like a solid stop. Also when the beam is emitting, you should only turn it a couple of degrees either way. Any further and you should shut it off and rotate it a full turn before trying again. This will ensure the crystal is aligned, and reduce the risk of damage. Another thing you could try with an old true 50 is, pull the diode and replace it with a 1watt (open can of course). That’s what im messing around with right now, and am getting 130-150mW. As I said, it’s all aboot playing around with the cheap stuff and just learning as much as I can.

 

[IgorT]

I cleaned all the glue out of mine, when i first took it appart, so when the crystals stop, they are touching the diode, which i don't wanna do. But as i said, i did find the optimal position of both the crystal and the diode, i just can't finish it without a meter, since right now it's down to just fractions of a degree and it can't be done visualy.

One more thing.. Did you ever measure the current with the TrueDX50s? If they are the same, the current should be between 500-700mA, depending on the batteries and the meter.

 

[JLSE]

Yeah that sounds aboot right.  If  I remember correctly mine came in at 600ma or so. Im curious if the pump is an underdriven 1watt. So far all the china diodes on ebay that are 9mm and multimode are 1 watt. If this were the case, you should be able to push 1400ma. The true 50 doesnt seem to get all that warm, and the 1watts I have dont get warm with the driver from a true 50, but only when you feed 1amp+. And seeing as they can push 200mw on the pointer (or so they say) that would only be a 20% efficiency for a 1watt. It may in fact be a 1watt pump

 

[IgorT]

The DX200 does get quite warm, even on the outside. And since the inner module isn't really touching the outer shell, it must be hot inside. The one i have now is somewhat stable after warming up and before becoming too hot (when it splits in four beams).

But while warming up it does something very weird. It comes on at full brightness but slowly gets dimmer and then it suddenly jumps quickly up to full brightness again. It repeats this three or four times, depending on how warm it was at the start. If it's warm from before it only does it once.

Have you ever seen this behaviour? Any ideas, what could be causing it? I measured the current, and it remains completelly stable during this, so it's not an electrical problem. Must be something with the crystals.


BTW: You actually tried feeding these diodes >1A?

 

[JLSE]

I would imagine the crystals have something to do with it. Mode switching seems to revolve around the ability for the crystals to dissipate heat and when they are cold. Im in Toronto Canada, and this winter was pretty cold, all my greens seem to hate this weather, but behave with less issues after some warm up time (as is normal). The crystals are held by that adjustable brass piece, and if you notice there is a bunch of thermal paste in the threads. It may also be possible to eliminate some of the mode problems by replacing the paste with a higher quality type. I ordered the little tubs of paste they use, id imagine it’s the same and its seems to be the cheap china alternative. Mind you I haven’t tested the differences, but I only use with TEC and heatsinks, I save the good stuff for the diodes. Also I haven’t tried 1amp, but it’s possible that someone on LPF has. I tend to give the cheap parts to a friend who is also into the greens, I keep the brass housings and in some cases the boards, and put my better parts back in. Another thing to, is that the 50's may be sold as 50's when the crystals or the pump is damaged. I’ve put together greens with a 1watt, and yield 150mw, and then press my luck, tighten the crystal down too much causing damage, and the result is 50mw and no higher. So really it’s hard to say what causes the differences between the 50 and the 200, but it probably revolves around these types of actions. A unit that kicks 150 and is then damaged will not hit 150 again, but will make for a reliable 50mw with no mode problems.

 

[IgorT]

It turns out i'm returning both DX200s for a replacement. And this time there is actually a possibility i might get a working unit or even two if i'm lucky. Can't be much worse anyway.

When i contacted them about the problems with the first one, and said i would keep it and buy another one if they make sure it works, Rain from DX responded immediatelly. Unfortunatelly the testing he did didn't really help much and the second one was defective as well. Now he is completelly ignoring my emails and pleads for help.

While arranging the return i again asked if they can test it, but i was unlucky and got the response "Unfortunatelly we must test it before shipping to ensure the quality. Please understand."

No amount of tickets and explaining, that this is what i want helped. The person i was talking to simply didn't understand me.


Then i got annoyed by it, and decided to return the first one as well, again asking if i can tell them exactly how to test it.

Someone else responded this time, someone who actually can speak english, and they said, they would be pleased, if i could explain the testing procedure to them, so they could ensure better quality of all lasers in the future.


At the moment i'm preparing pictures, videos and detailed descriptions of how to test the lasers and spot the problems. I need to keep the language simple even tho what i'm explaining is complicated. But i hope all the good/bad comparison pictures will help.

If they would actually do the testing with all lasers, it could mean better quality in the future. I think it's in their best interest as well, as it costs them to pay shipping twice and reimburse the return shipping.


I guess we shall see.

 

[JLSE]

It seems DX breaks out the english speaking customer support when the one helping gets confused. I have experianced similar with them. Annyway here is a link for the crystals you were asking about. Sometimes he sells the glued + KTP, but the only one he has now is for 1064nm. Keep an eye on him, I delt with him a while back, and he usually has some cool stuff up for sale


http://cgi.ebay.com/KDP-Crystal-2x2...yZ109452QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


cheers.

 

[GooeyGus]

I actually have a piece of crystal that looks about that same size as the one in that auction. Its like a rectangle rather than just a cube, it looks like two cubes put together (but as one single piece) and then has the additional cube crystal (that has that greenish look to it) glued onto it. Would this possibly be a better crystal than the standard ones that come in the DX lasers, which appear as a single piece?