Rominsen L-D030 >150mW mod

[IgorT]

Ok, so i succesfully extracted the other DX200 - the one i expected to have a cold solder joint, since it didn't work with batteries inside... :

There was no bad solder joint, so i don't know what was wrong with it. But this laser is capable of delivering a much nicer power VERY stably. Since i don't have time to work on a driver now, i took the CNI driver off the unstable one, and put it on here, mounted in a vice, and got 125 - 130mW! Increasing the current wouldn't help much, even tho i saw it peaking at 150mW in it's original state with Ni-MHs. No idea about the current of course. Need to test that later.

I lowered the power to 120mW and mounted it into the Rominsen body temporarily. Even tho i have not perfected the heatsinking yet, just the force of the head pushing the module down makes it dissipate a lot of heat. The power is completelly stable at 130mW! Higher, than in the vice! Didn't expect this... But i guess the crystals were warm due to all the current adjusting.


Finally success! I guess this will be my second favorite green for a while. I put on a spare <0.5W warning label from CNI, like the ones that come with Nova X-series. It's actually quite an impressive laser now.

The divergence is similar to the CNI and due to the amazing driver (only 0.39V dropout voltage!) it can operate perfectly from a regular 3V CR123 or a 3.6V Li-Ion CR123 with the same perfectly stable current. The beam is visually almost exactly as bright as my >150mW CNI pen. It's lower power, but actually more stable! And for some reason it does not get as hot as the "KDX200". Maybe because of as of yet incomplete heatsinking. But if it is that, it will become even better when complete!


I love this little laser! Later i will try to set the power to 150mW and complete the heatsinking. But the results so far were great for so little work.

Pics also later, need to sleep.


EDIT: Can't sleep. Pics now...

 

[IgorT]

And the measurement.. It would only move between 126 to 128mW.. It's incredibly stable!

And i took it out immediatelly after use, and the module wasn't even warm! I don't get it. It's much lighter than the KDX200 but that one gets HOT. Here the head is much more massive, but in a separate piece. And i have not used thermal grease yet at all.


BTW, i took the 200mW Rominsen pump out to try it with KD50 crystals, and it actually had thermal paste on the diode on top and below the base! First time i saw this. It actually scared me a little. Had to clean it off carefully not to mess up the die...

Anyway, here's a pic of the measurement of this little monster.

 

[IgorT]

And again, it happens.. I improve the heatsinking, and the power goes down...

The crystals sometimes like being warm. Maybe the previous amount of heatsinking was just enough for the crystals to get into a good efficiency range, but not overshoot. Maybe now they don't get warm enough?

With improved heatsinking, i can feel the warmth outside after a while. Before i couldn't, but the power was higher. I certainly hope i didn't damage anything, and that it goes back up when i remove what i added...



EDIT: Indeed. I remove the heatsink, and the power jumps back up to the previous level and is stable. Very interesting. It would seem, that the pen is actually the best amount of heatsinking for these.. Need to try to decrease the heatsinking in the other one.

Strange lasers...

 

[thejunkmonger]

Re: Rominsen L-D030   >150mW mod

And again, it happens.. I improve the heatsinking, and the power goes down...

The crystals sometimes like being warm. Maybe the previous amount of heatsinking was just enough for the crystals to get into a good efficiency range, but not overshoot. Maybe now they don't get warm enough?

With improved heatsinking, i can feel the warmth outside after a while. Before i couldn't, but the power was higher. I certainly hope i didn't damage anything, and that it goes back up when i remove what i added...



EDIT: Indeed. I remove the heatsink, and the power jumps back up to the previous level and is stable. Very interesting. It would seem, that the pen is actually the best amount of heatsinking for these.. Need to try to decrease the heatsinking in the other one.

Strange lasers...

I have noticed that with all the greens i've had (3) they all need to heat up a bit before giving full power my Romisen starts up in TEM 1 for a split second and as it heats up goes to TEM 0 . Both of my Dx trues give a burst of high power when I turn them on and then die down in a split second until you have had them on for awhile or you start turning it on and off. The modded dx true 30 running at 4.5 volts goes to full power instantly and stays there.

 

[IgorT]

Yeah, i've seen all sorts of greens. I have some, that drop with heat, and i've had some, that climbed with heat. But it would seem, that both types need an initiall warm up - the efficiency increases with temperature climbing up to a certain level, but after that, it depends on the crystals obviously. One can continue climbing and the other can start dropping again...

I just verified this on the Rominsen-DX200. After removing the heatsink "connector", there is still some thermal grease left inside, so the heat has a better path to dissipate, than it did before. But this means, the laser starts at a lower power and slowly climbs to where it would quickly end up before... Very interesting.

The other one is still mode hopping. It used to mode hop cold and very warm. But now it is getting hot, the power is lower and it mode hops quite fast.. When i get the replacement Rominsen i'll try that for a transplant as well, see if it's any better. Then i'll try to reduce the heatsinking, see what happens. It helped here.


It would seem, that some of these lasers are imperfectly heatsinked on purpose... You have to hit the sweet spot with everything, when it comes to greens.



Otherwise, i really like how small this powerful laser looks. Due to the odd shape it looks smaller than the KD50, even tho it is actually a bit longer now. Side by side it is obvious, that it is larger, but by itself, it looks quite tiny. And after the mod it packs some real power!

 

[IgorT]

Benm: Do you have an idea, how i could measure the actual max current this laser operates at, in it's original state, without influencing the measurement?

Due to the fact the original DX200 driver doesn't do anything, the current can be cut down by a third simply by putting a DMM in 20A range between the laser and the batteries. So i have no idea what currents it normally operates at, with various batteries.

On a PSU set to 3V it would actually pull a VERY high current and maybe even kill itself if i didn't limit it. This doesn't really tell me much, due to the fact, that the batteries sag.. I know some people use Lithium AAAs in it, and get good results, so maybe it can take those currents. I've also heard of it being used with a 3.6V 10440 Li-Ion, with good results. When i did this through my DMM, the current was 730mA but without the DMM it would again be higher.

If i had this info, i could adjust it better, now that it is properly regulated, and maybe get more out of it.


If i measured the battery voltage under load, and then set the PSU to that same voltage, and took the current reading from the PSU, would that give me the correct results?

Otherwise, i just remembered, there are three SMD 1 Ohm resistors soldered in parallel on top of each other on the original circuit. It might be as easy as measuring the voltage drop across them.


I think it's quite likely, that these three resistors in parallel are what does the "regulation" on this "driver". I connected it to an 1A LED and varied the voltage, and the current changed with the voltage all the time.

The original Rominsen driver is nicely regulated tho. Not perfectly - there is up to 20mA change with varying input - but above a certain voltage, the current doesn't change anymore. And the dropout would seem to be very low.

 

[IgorT]

Ok, i have just confirmed, that this laser actually works at a lower power with better heatsinking.

After i removed the aluminum between the module and the body, the power jumped by 10-20mW. But i was adjusting the current again, so i thought i would just use some thermal paste on the edges, where it touches the aluminum body.

The power suddenly dropped to 110mW again! If i leave it on now, i can feel it getting warm. After a few minutes, the entire body gets very hot! The heatsinking works very good from a very small contact area (just the edges)... But after the entire body heats up, and the heat has nowhere to flow anymore, the power suddenly starts climbing. It ended up above 140mW. Close to 150mW actually!


So if the heatsinking is bad the crystals heat up faster, and reach the max efficiency sooner. With good heatsinking, the heat flows away, and they reach max efficiency later.

But in the first case, they also overheat, and lose efficiency again, while in the second, it ony grows and grows.


It's hard to find the perfect amount of heatsinking for perfect results.. But i put the good one in the aluminum Rominsen body. Maybe i should try the good one in the KD50 body as well. Could actually become better due to less heatsinking. :-?

 

[thejunkmonger]

Re: Rominsen L-D030   >150mW mod

with my first dx true 30mw I got great results before modding it to 4.5 volts by heating it up on the radiator in the house and then turning it on.

 

[IgorT]

Well, this little thing is quickly becoming my favorite laser. It wasn't as expensive as the CNI, so i don't have to be as careful with it, so i guess i'll actually use it more in the end.


It's quite good at the moment. I'm gonna try to improove the other one a bit as well. But it's mode hopping. The next Rominsen should come soon, and may provide enough cooling tho.

 

[thejunkmonger]

Re: Rominsen L-D030   >150mW mod

Good luck Igor I tried the same trick of boosting voltage on the dx30 to 4.5v with no luck it mode hops like crazy. ARGGGG

 

[IgorT]

Well, since these are not regulated, it pushes a much higher current through them. I'm surprised they survive. I am so gentle with my DX200 pumps. I don't dare go above 750mA, even tho i heard 800, 850 and close to 1A.

I might eventually try with the mode hopping one, or maybe not, i don't know. First i want to see if the Rominsen can cool it down below the point of mode hopping.

 

[IgorT]

There is one thing i don't like about this Rominsen.. At a certain point the battery tube wall suddenly becomes thicker. That is good for heatsinking, but id doesn't really allow the use of protected rechargables. If this was 3mm deeper it would be great. The spring would give way, and the tailcap could be screwed on completelly. As it is, it can only be screwed on up to the O ring with a protected Li-Ion. After that it starts crushing it


I don't see any simple way to change this. It's deep enough to be hard to reach, but not deep enough for the battery. Quite annoying actually, cos i also wanted it for the larger battery and longer duration.


The CNI driver is truly amazing tho. A transistor on it does get very hot unfortunatelly. Hotter than in its original environment i guess, due to a higher voltage of a Li-Ion, but it has not failed me yet. I wish i had more of these amazing drivers.


EDIT: Looks like i managed to get it pretty stable. It comes to 135mW fast and stays above 120 for two minutes. It takes five minutes total to get to 110mW and seven to get to 100mW. The body heats up, but not as much as the "KDX200"

That one peaks at >150mW, but drops much faster and goes into TEM01. Only bright side is, that it doesn't lose any brightness when it splits. The power stays the same, only it is spread out between two beams. This one might do better as a labby with a peltier.

 

[IgorT]

Good luck Igor I tried the same trick of boosting voltage on the dx30 to 4.5v with no luck it mode hops like crazy. ARGGGG

That's because of bad crystals. Not much you can do about that. I had to order two DX200s and RMA both, to get one without mode hopping.

I'm surprised, that these lasers can take an extra battery. They are not regulated, so the current must be much higher. The diodes seem to be very sturdy.

If you want to improve the behavior of a green, you first need current regulation, and you can try improving heatsinking. Then you need to find a current, where it wouldn't mode hop. Sometimes it helps, but often not. Generally tho, it's not a good idea to just throw in an extra battery into a non regulated laser. The current should be increased only slightly, if at all. And for that you need to fiddle with the circuit.



BTW, even tho i improved everything about the DX200, that i stuck into the Rominsen, it still behaves weird. If i power it up, it comes on at only 100mW. I have to turn it off and on again, and then it reaches >130mW, and actually stays there! This, i don't undestand. :-?

 

[thejunkmonger]

Re: Rominsen L-D030   >150mW mod

[quote author=thejunkmonger link=1209508565/30#41 date=1211062327]Good luck Igor I tried the same trick of boosting voltage on the dx30 to 4.5v with no luck it mode hops like crazy. ARGGGG

That's because of bad crystals. Not much you can do about that. I had to order two DX200s and RMA both, to get one without mode hopping.

I'm surprised, that these lasers can take an extra battery. They are not regulated, so the current must be much higher. The diodes seem to be very sturdy.

If you want to improve the behavior of a green, you first need current regulation, and you can try improving heatsinking. Then you need to find a current, where it wouldn't mode hop. Sometimes it helps, but often not. Generally tho, it's not a good idea to just throw in an extra battery into a non regulated laser. The current should be increased only slightly, if at all. And for that you need to fiddle with the circuit.



BTW, even tho i improved everything about the DX200, that i stuck into the Rominsen, it still behaves weird. If i power it up, it comes on at only 100mW. I have to turn it off and on again, and then it reaches >130mW, and actually stays there! This, i don't undestand.  :-?[/quote]

yes basically my dx 30 does the same kind of thing, coming from someone that knows nothing it's like I need to precharge the crystals let them drain a second and then hit them again.

 

[IgorT]

yes basically my dx 30 does the same kind of thing, coming from someone that knows nothing it's like I need to precharge the crystals let them drain a second and then hit them again.

So with that one this difference is noticable?

I don't actually see the difference unless i am measuring it. So if i'm playing with it, i'm worried, it is at only 100mW. So i learned to power it on/off/on and that way i know it is working at 130mW.


I need to experiment with the currents a bit, to see if it has something to do with that. Otherwise, i really don't understand it. It is current regulated for gawds sake. I kinda thought i would get more improvement, but i don't actually know what the original current was.



Anyway, here's a pic of a measurement with my KDX200 Frankenstein laser. It is peaking at just above 150mW. I can't get this power out of the "Rominsen" but at least it is more stable and averages much higher in comparison.

 

[IgorT]

Some more beam shots for your enjoyment...

The KDX200 and Rominsen L-D200 side by side, with a little "beam enhancers".