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574nm 36 mW Yellow Laser

LOL, I’ve been a component level technician my entire 45 year working life. I saw the rectifier diodes and filtering, just didn’t want to make assumptions without being able to see the traces.
 





Can't blame you for being cautious. We don't want one of these Unique Yellows to blow up.

The information about the driver being A.C. was around somewere. I don't recall were I read it though.


These drivers do seem a bit strange. They seem to have a Switching Regulator then an Analogue Regulator after it. The Transistor near the Diode output terminals does get quite hot. They don't seem to be rated for a 2 Watt diode.
 
I'm having problems with mine when the DC input is above 8.0 volts, after running a couple of minutes or more the beam then begins blinking out about every ten seconds for about a second. Also, mine needs about 9 VDC to keep the beam brightness up to full output. At 8 VDC, I'm getting about 90 percent full brightness (using my very uncalibrated eyes), my LPM has a blown fuse tonight so I can't measure the power variations :(

However...... Good news is after I added a small copper heat sink to the regulator I can then turn the voltage up to 9 VDC to get full brightness without it blinking out. I'm doing this in a room cooled to about 68 F, if it were hot in the room, I doubt the laser would remain stable at 9 VDC as this appears to be a heating problem with the driver and my heat sink is just too small.

As reported earlier by another member, this driver is unsuitable for this laser, once I get just a couple tenths above 9.0, the laser starts blinking off and on periodically. Perhaps a large heat sink will fix the problem, but not much room to add a larger heat sink, a taller one would help, maybe gluing the heat sink to the device would also help as the one I have is just using an adhesive square.

 
Between the two yellow laser topics I've lost track of the similarities or dissimilarities of each. If any member has both units could they comparatively describe each? Thanks.
 
Mosc007 said:
These drivers do seem a bit strange. They seem to have a Switching Regulator then an Analogue Regulator after it. The Transistor near the Diode output terminals does get quite hot. They don't seem to be rated for a 2 Watt diode.
Click to expand...


That's actually not all that uncommon. If the input voltage is much higher than the output voltage you can use a switching supply to drop the voltage down before the linear regulator. Much more efficient than just driving the linear regulator at a higher voltage.

My big Q-switched laser does exactly the same thing. 12V supply->Switching regulator (~4V)->Linear current regulator->Diode(~1.8V).
 
I used Thermal Adhesive to bond the Heat sink to to the transistor. I have also added one to the switching regulator as well. It's the small IC opposite side of the case to the transistor, near the fan plug. I have never had it shut down running off 12 volts.
 
Thanks, I will need to do that too, I felt the heat under there too, but didn't look further tonight, it's very hot.
 
Ultracrepidarian said:
On May 29th they said they will ship my yellow laser "this week", 8 days have passed and they still haven't shipped it and when I ask them when will they ship they don't reply but I see that they read my message, this is starting to concern me.
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You don't say which unit you ordered. I ordered two of the Oplaser units from Alibaba on May 25th. Got notification on Mon June 4th my order was being prepared to ship.

Got a text on Tues the 5th that they were in transit and would arrive by Weds the 8th by 8pm.

They actually showed up about 3pm!

I have only just powered both units up to make sure they work, and they do!

Very, very nice yellow!!!
 
When you heat sink the driver IC make sure to keep it away from the large electrolytic cap. If you place the heat sink directly over the IC it will contact the cap and cause it to run hot too. Just a heads up before you use adhesive.
 
Grn05gt said:
You don't say which unit you ordered. I ordered two of the Oplaser units from Alibaba on May 25th. Got notification on Mon June 4th my order was being prepared to ship.

Got a text on Tues the 5th that they were in transit and would arrive by Weds the 8th by 8pm.

They actually showed up about 3pm!

I have only just powered both units up to make sure they work, and they do!

Very, very nice yellow!!!
Click to expand...

That's great that yours arrived.
I ordered mine from Optlaser on the 23rd I think and just yesterday he said to wait two more days:confused: Odd how yours arrived before mine shipped. At least I know mine should arrive sometime.
I've got two of each wavelength coming so that I can use the "extra" ones to test on. Should be fun!:eg:
 
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Chris, if you will refer to the first photo in the OP you can see I applied +12 volts to the plug next to the one you have used. Can't say if or how much of a difference this would make as my driver in secured with glue to the plastic enclosure and I didn't access the bottom of the board to see how this driver was set up. You might also want to heat sink the driver IC as shown in that same photo. It runs very hot as well.
 
Mattronium said:
That's great that yours arrived.
I ordered mine from Optlaser on the 23rd I think and just yesterday he said to wait two more days:confused: Odd how yours arrived before mine shipped. At least I know mine should arrive sometime.
I've got two of each wavelength coming so that I can use the "extra" ones to test on. Should be fun!:eg:
Click to expand...

I have seen from this thread and the other, that some of you have been contacting the seller directly to place orders, as you said "he". I just went to the link https://wholesaler.alibaba.com/prod...cient-garden-laser-animation_60746590781.html

and ordered from there. Comm was great and I got what I ordered. It says delivered 18:40 on the waybill, but I got it before 16:00.
Still, 2 days from pickup in HK to my door in Fla, USA, not bad!

I guess the ones I got are 565nm, there was no option between 565/575, they have the slight green tinge to them, still looks an awsome yellow though. Better than mixing red and green with poor beam overlap!
 

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I got mine in less than four days from pickup to delivery. I think if you want the 575nm laser, you need to contact Freeman B. at fb@optlaser.com. That is how I got mine.
 
I can't see all the numbers, but it's basically input -> bridge rectifier -> DCDC converter -> linear current sink.

lm358 is a cheapy "jelly bean" op-amp being used to drive the 3A NPN and sense current via the 2 1R0 shunts. The NPN is only rated to dissipate 1.2W even with good heat sinking, which means they've chosen a very poor transistor for this application. Can anyone measure the DCDC converter output voltage? For the uninitiated, that would be the voltage with the red probe on the red laser lead, and the black probe on pin 4 (top left in Alaskan's photo) of the lm358. Also, what is the DCDC converter IC? Also the collector-emitter voltage? Pinout of a similar device for reference:

mjd47-pinout.jpg


Suggestion 1: If you are running these on DC: Wire a link to short out D1 and D3 to defeat the bridge rectifier. This will allow ~1.4V lower input voltage (and 700mW less heat generated) with no ill effects

Suggestion 2: Replace the NPN here with... basically any TO-220 style NPN you have lying around. Bolt this to a proper heat sink.
 
With your mod it should be able to work on 2x18650. I think I'll try that once mine arrives.
 
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