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Ahhh Seb, Now you see what Im talking about with these drivers.
That overshoot scares the hell out of me. I would never succomb a diode to this punishment.!!!
Its happening at a very slow speed which makes it dangerous for the diode.
Ive seen early CNI's do this but at the top end. especially the Blues. But I expect the greens to be the same.
What you are describing to me sounds like a diode issue. Altho Its possible the driver could have gone bad.
Or caused it..dunno for sure
Imaging a mesh. Then imaging not one mesh but about 5-6 meshes put together. This is your pumping element. (I know its really stupid visualizations but still...) When you blow it. It doenst blow all 6 meshes but only 3-5. So the pumping element still works.....but only gives 30-50% of power.Quote:
Originally Posted by sbk
Yes Chuck I see ;)
Anyway these drivers are very sensitive to electric connections and grounding. With my 100mW blue if I don't wire correctly all the ground (from main power supply to laser power supply to the head), I have only an output of 40mW, and the red and green LEDs on the driver are always ON...
To be sure I disconnected all the other electronics to measure the power again, but there is no improvement.
I measured 3.7A total current at full power on the 5V power supply. Anyone that have a 532nm Lasever of 200mW (or any power) already measured that current?
I have a 150mW but don't trust myself to measure the current out of the power supply.
Allthat : it's simple if you have an amperemeter, just connect the +5V cable from the main power supply (which normaly goes to the laser driver positive input) to an amperemeter input (which is marked 10A or so), and connect the other amperemeter pin (COM) to the laser driver (where you just removed the original cable).
But don't do it if you're not sure you're not obligated, I don't want to scare you :)
http://img291.imageshack.us/img291/1...measureyo7.jpg
I thought it was between the head and driver where you took readings. :o My 5volt has a plug on it though, like a laptop... :confused: Do multimeters have ampmeters? Mine has something that has 10A on it. :D
Yes you can measure the current between head and driver, it but it's more tricky and risky to do (but will be the right way, will give the pump diode current only). I don't do it because I don't want to lose the warranty :)
In the power supply cable you'll measure the total current (TEC + diode + electronic components) but it give an idea of what occurs with your laser...
I think you'll have to cut your cable with the plug to measure the current, so don't do it unless you'll use another power supply...
Yes a multimeter has an amperemeter normaly, if you can read something like "mA" or "A" near a buttons :D
;)Quote:
Originally Posted by sbk
I guess I won't do it then. Since David was kind enough to replace my last one that died, possible by my own hands, I won't tempt fate again. :rolleyes:
Sure ;)
So, someone else has a Lasever? :D
SBK;
Quite a few of us have Lasever lasers here. Unfortunately, recently there have been quite a few failures.
I haven't had *any* trouble with my older Lasever DPSS green unit with the large "U" series head and the large, boxed power supply. (The one with the vernier current control and digital readout of diode drive current.) But that unit only supports TTL modulation. Still, it's nearly 5 years old now and still works great.
The newer "ML" series heads have experienced a *lot* more failures - especially with the DPSS blues. I know of one member here that is on his 3rd blue laser in less than a year. (The first two failed.) If you search through the forums you'll quickly see that the rash of failures started last year and have been getting more frequent ever since.
David Wu says that he and his coworkers are still searching for the source of the problem. He also said that he will replace any lasers that fail within the warranty period, although lately he has been hard to contact - presumably because he's busy looking for a solution to the problem with the smaller "ML" heads.
Aaron;
I only test total current draw. In order to test just the drive current, you would need to disconnect the cable between the driver and the head, then wire each pin from one end of the cable to the corresponding socket on the other conenctor, making sure you leave room to insert your multimeter on the correct wire to measure the drive current. Not only is this risky from a wiring point of view (if you wire it wrong, you can fry the diode), but just disconnecting the cable between the head and the power supply can blow the diode due to static. With the cable disconnected like that there is nothing to prevent a slight static charge from zapping the pump diode. You *really* need to be careful if you're going to do this. Personally, I don't think it's worth the risk.
Now, on bare diodes where you're already at risk for blowing them with static because they're not conencted to anything, I have checked drive current. But I've also blown a diode doing that. (One out of 3.) DVD diodes are cheap, so I wasn't too concerned. But there's no way I'd try that on a $1000 + DPSS blue head! (I'm not that curious!)
Adam