Lasever 200mW 532nm

[PNjunction]

I was scared of trying three things as a kid... glue, dust, and heroin. However, now I do it all the time! Kidding, kidding...

Other things were quite fun though.

[sbk]

Well, what was supposed to arrive, arrived... My laser (originally >260mW) is only giving 90-120mW, and this after only <10 hours of use
I heard that there was a lot of bad experiences like that (especially on the Laserfreak forum), so is it considered as "normal"?
What can be the cause? The laser was correctly cooled, it was not even warm.

I think the best thing to do is to return it to Lasever?

[allthatwhichis]

I would definatly talk to David. My 150mW did close tot he same thing after about two weeks. It's power slid down to about 20 to 30mW. After a few PMs he had me send it back and he sent me out a replacment. I haven't had any problems with this one, but I have only had it about two weeks also. David mentioned I may have ESD'd it when using the 5 volt supply off the laser to warn it up before plugging the cable from my computer to projector... Now I try to keep my fingers away from the plug.

[buffo]

SBK;

Saddly, I've read of several Lasever DPSS laser failures recently, and every one of them is just like yours. One day the laser is making it's rated power, and the next day power has dropped off to a fraction of what it should be. In all cases the head and the driver board remain cool.

I have a 110 mw Lasever blue DPSS laser right now that is only making 40 mw. David Wu (Lasever rep. from China; goes by "Lasever" here in the forums) is supposed to be sending me a replacment laser, but it's been over a month and I'm still waiting.

EDIT: My replacement laser arrived on 6-19-2007

In David's defense, he did say that he and others at Lasever have been working long hours trying to find the source of these failures.

Either way though, your laser is going to have to be returned for repair. (Sorry...)

One question: Do you have the older "U" series head (looks like a brick), or the newer, smaller head design with the round turret in the front where the beam exits? The reason I ask is that the failures seem to be far more common with the new, smaller head design. Just curious...

Adam

[Dr Laser]

Power supples have to have a good power protection against surges to pumping elements. Also never disconnect and connect a head from power supply while a head is running. It will kill about 70% of pumping elements the result.....70% power loss. Usually its not a head or pumping elements....its a power supply. Badly designed.

[sbk]

Allthat : yes I'll talk to David of course... I'm sure it's not a ESD problem, I take a lot of care to this when working with my lasers, I'm always connected to ground.

Buffo : yes it's the smaller design. If the failures happens more often with the small design, maybe the cause can be an internal temperature problem (which we can not sense by touching the unit). The TEC is certainly less powerful than in the older one. It can be a problem when you blank the laser for a long time and switch on again fastly to full power...

Yes power supply have to avoid peak voltage/current on modulation for example. Germans on Laserfreak forums have measured this (they have a lot of defective green/blue lasever among their members) :

Type : 200mW green Lasever
Black curve : modulation signal
Green curve : pump diode current

Note that there's a current peak at every rising edge, at 100Hz modulation...



And of course, I didn't disconnected the laser head from the power supply when running

Now I'm thinking, when turning off the laser, the TEC will not be powered any more, and its hot side will quickly overload its cold side, so maybe overheating the diode... Is it possible?

[Dr Laser]

One of my greens has a power down delay. Its about a second after you turn switch off. Instruction says to WAIT until it powers down.

[steve-o]

I know on my argon when I power down I leave the fan going until the heat sink temp is down to 150 degrees F

[sbk]

I think the best way to shut down is to blank the laser for a few minutes (so the TEC and the case can cool down), and then completely shut down the power supply. But if the cooling is sufficiant so the entire system remain cool, it's no more essential...

But a thing that I can't understand is, how the laser can still give power without any sign of damage on the beam or so, but give only an output of a fraction of rated output...

[sbk]

A strange new thing that I just discovered : when I power the laser, put a few volts on the blanking input, and then put 0V (even disconnect the blanking), a little output of 532nm light remain for some seconds, and is not very stable... This wasn't the case before the failure.
So is it possible that it's a driver defect and not inside the head?